diff --git a/src/app/helpers/books.ts b/src/app/helpers/books.ts
index c0f814e58..060983490 100644
--- a/src/app/helpers/books.ts
+++ b/src/app/helpers/books.ts
@@ -8,6 +8,11 @@ export type Book = {
     subjects: string[];
     title: string;
     content_warning_text: string;
+    assignable_book?: boolean;
+    kindle_link?: string;
+    has_faculty_resources?: boolean;
+    has_student_resources?: boolean;
+
 };
 
 const statesToInclude = ['live', 'new_edition_available', 'coming_soon'];
diff --git a/src/app/pages/errata-form/errata-form-context.js b/src/app/pages/errata-form/errata-form-context.tsx
similarity index 53%
rename from src/app/pages/errata-form/errata-form-context.js
rename to src/app/pages/errata-form/errata-form-context.tsx
index b8a98093a..718edd4f6 100644
--- a/src/app/pages/errata-form/errata-form-context.js
+++ b/src/app/pages/errata-form/errata-form-context.tsx
@@ -1,30 +1,51 @@
 import React, {useState} from 'react';
 import buildContext from '~/components/jsx-helpers/build-context';
 import fetchBooks from '~/models/books';
+import {type Book} from '~/helpers/books';
 import {useLocation} from 'react-router-dom';
 import {useDataFromPromise, useDataFromSlug} from '~/helpers/page-data-utils';
 
+type ContextValue = {
+    selectedBook: Book | null;
+    books: Book[] | null | undefined;
+    hasError: string | null;
+    setHasError: (error: string | null) => void;
+    hideErrors: boolean;
+    submitting: boolean;
+    validateBeforeSubmitting: (event: React.FormEvent) => void;
+    searchParams: URLSearchParams;
+    title: string | null;
+    setTitle: (title: string) => void;
+};
+
 function useSearchParams() {
     const {search} = useLocation();
 
     return React.useMemo(() => new window.URLSearchParams(search), [search]);
 }
 
-function useContextValue() {
+function useContextValue(): ContextValue {
     const searchParams = useSearchParams();
-    const initialTitle = React.useMemo(() => searchParams.get('book'), [searchParams]);
-    const [title, setTitle] = useState(initialTitle);
+    const initialTitle = React.useMemo(
+        () => searchParams.get('book'),
+        [searchParams]
+    );
+    const [title, setTitle] = useState<string | null>(initialTitle);
     const books = useDataFromPromise(fetchBooks);
     const selectedBook = React.useMemo(
-        () => books?.find((b) => b.title === title) || {},
+        () => books?.find((b) => b.title === title) || null,
         [books, title]
     );
-    const bookInfo = useDataFromSlug(selectedBook.slug) || selectedBook;
-    const [hasError, setHasError] = useState('You have not completed the form');
+    const bookInfo =
+        useDataFromSlug<Book>(selectedBook ? selectedBook.slug : null) ||
+        selectedBook;
+    const [hasError, setHasError] = useState<string | null>(
+        'You have not completed the form'
+    );
     const [hideErrors, setHideErrors] = useState(true);
     const [submitting, setSubmitting] = useState(false);
     const validateBeforeSubmitting = React.useCallback(
-        (event) => {
+        (event: React.FormEvent) => {
             event.preventDefault();
             setHideErrors(false);
             if (!hasError) {
@@ -37,7 +58,8 @@ function useContextValue() {
     return {
         selectedBook: bookInfo,
         books,
-        hasError, setHasError,
+        hasError,
+        setHasError,
         hideErrors,
         submitting,
         validateBeforeSubmitting,
@@ -49,7 +71,4 @@ function useContextValue() {
 
 const {useContext, ContextProvider} = buildContext({useContextValue});
 
-export {
-    useContext as default,
-    ContextProvider as ErrataFormContextProvider
-};
+export {useContext as default, ContextProvider as ErrataFormContextProvider};
diff --git a/src/app/pages/errata-form/errata-form.js b/src/app/pages/errata-form/errata-form.tsx
similarity index 71%
rename from src/app/pages/errata-form/errata-form.js
rename to src/app/pages/errata-form/errata-form.tsx
index fb3bc1713..4ad9739af 100644
--- a/src/app/pages/errata-form/errata-form.js
+++ b/src/app/pages/errata-form/errata-form.tsx
@@ -1,11 +1,17 @@
 import React from 'react';
 import Form from './form/form';
 import FormSelect from '~/components/form-select/form-select';
-import useErrataFormContext, {ErrataFormContextProvider} from './errata-form-context';
+import useErrataFormContext, {
+    ErrataFormContextProvider
+} from './errata-form-context';
 import useUserContext from '~/contexts/user';
 import linkHelper from '~/helpers/link';
 import './errata-form.scss';
 
+type Book = {
+    title: string;
+};
+
 function ErrataForm() {
     const {title} = useErrataFormContext();
 
@@ -26,22 +32,29 @@ function ErrataForm() {
 function TitleSelector() {
     const {books, setTitle} = useErrataFormContext();
     const options = React.useMemo(
-        () => books?.map((book) => ({label: book.title, value: book.title})),
+        () =>
+            books?.map((book: Book) => ({
+                label: book.title,
+                value: book.title
+            })),
         [books]
     );
 
     return (
         <div className="text-content title-selector">
             <p>
-                It looks like you got referred here but they didn&apos;t tell us what
-                book you were looking at.
+                It looks like you got referred here but they didn&apos;t tell us
+                what book you were looking at.
             </p>
             <FormSelect
+                name="title-selector"
                 selectAttributes={{
                     placeholder: 'Please select one'
                 }}
                 onValueUpdate={setTitle}
-                label="What book were you in, again?" options={options} />
+                label="What book were you in, again?"
+                options={options ?? []}
+            />
         </div>
     );
 }
@@ -64,7 +77,13 @@ export default function EnsureLoggedIn() {
             <main className="errata-form page">
                 <div className="boxed">
                     <div>You need to be logged in to submit errata</div>
-                    <a className="btn primary" href={linkHelper.loginLink()} data-local="true">Log in</a>
+                    <a
+                        className="btn primary"
+                        href={linkHelper.loginLink()}
+                        data-local="true"
+                    >
+                        Log in
+                    </a>
                 </div>
             </main>
         );
diff --git a/src/app/pages/errata-form/form/ErrorLocationSelector/ErrorLocationSelector.js b/src/app/pages/errata-form/form/ErrorLocationSelector/ErrorLocationSelector.js
deleted file mode 100644
index 541bbd822..000000000
--- a/src/app/pages/errata-form/form/ErrorLocationSelector/ErrorLocationSelector.js
+++ /dev/null
@@ -1,60 +0,0 @@
-import React, {useState, useRef, useEffect} from 'react';
-import useErrataFormContext from '../../errata-form-context';
-import managedInvalidMessage from '../InvalidMessage';
-import TocSelector from './toc-selector';
-import './ErrorLocationSelector.scss';
-
-function AdditionalLocationInput({value='', readOnly=false, updateValue, required=true}) {
-    const inputRef = useRef();
-    const [InvalidMessage, updateInvalidMessage] = managedInvalidMessage(inputRef);
-    const syncValue = React.useCallback(
-        (event) => updateValue(event.target.value),
-        [updateValue]
-    );
-
-    useEffect(updateInvalidMessage, [required, updateInvalidMessage]);
-
-    return (
-        <React.Fragment>
-            <div className="question">Additional location information, if applicable</div>
-            <InvalidMessage />
-            <input
-                type="text" name="additional_location_information"
-                placeholder="Describe where you found the error"
-                value={value} onChange={syncValue}
-                ref={inputRef} readOnly={readOnly}
-                required={required}
-            />
-        </React.Fragment>
-    );
-}
-
-function DefaultValue({defaultValue}) {
-    return (
-        <AdditionalLocationInput value={defaultValue} readOnly={true} />
-    );
-}
-
-function NotDefaultValue({defaultValue}) {
-    const [tocV, updateTocV] = useState();
-    const [addlV, updateAddlV] = useState(defaultValue);
-    const required = () => !tocV && !addlV;
-
-    return (
-        <React.Fragment>
-            <TocSelector required={required()} updateValue={updateTocV} />
-            <AdditionalLocationInput value={addlV} required={required()} updateValue={updateAddlV} />
-        </React.Fragment>
-    );
-}
-
-export default function ErrorLocationSelector() {
-    const {searchParams} = useErrataFormContext();
-    const defaultValue = searchParams.get('location');
-    const readOnly = defaultValue && searchParams.get('source');
-    const Input = (readOnly) ? DefaultValue : NotDefaultValue;
-
-    return (
-        <Input defaultValue={defaultValue} />
-    );
-}
diff --git a/src/app/pages/errata-form/form/ErrorLocationSelector/ErrorLocationSelector.tsx b/src/app/pages/errata-form/form/ErrorLocationSelector/ErrorLocationSelector.tsx
new file mode 100644
index 000000000..75a08bdbe
--- /dev/null
+++ b/src/app/pages/errata-form/form/ErrorLocationSelector/ErrorLocationSelector.tsx
@@ -0,0 +1,92 @@
+import React, {useState, useRef, useEffect} from 'react';
+import useErrataFormContext from '../../errata-form-context';
+import managedInvalidMessage from '../InvalidMessage';
+import TocSelector from './toc-selector';
+import './ErrorLocationSelector.scss';
+
+type AdditionalLocationInputProps = {
+    value?: string;
+    readOnly?: boolean;
+    updateValue?: (value: string) => void;
+    required?: boolean;
+};
+
+type InputComponentProps = {
+    defaultValue: string | null;
+};
+
+function AdditionalLocationInput({
+    value,
+    readOnly = false,
+    updateValue,
+    required = true
+}: AdditionalLocationInputProps) {
+    const inputRef = useRef<HTMLInputElement>(null);
+    const [InvalidMessage, updateInvalidMessage] =
+        managedInvalidMessage(inputRef);
+    const syncValue = React.useCallback(
+        (event: React.ChangeEvent<HTMLInputElement>) =>
+            updateValue?.(event.target.value),
+        [updateValue]
+    );
+
+    useEffect(updateInvalidMessage, [required, updateInvalidMessage]);
+
+    return (
+        <React.Fragment>
+            <label
+                className="question"
+                htmlFor="additional_location_information"
+            >
+                Additional location information, if applicable
+            </label>
+            <InvalidMessage />
+            <input
+                id="additional_location_information"
+                type="text"
+                name="additional_location_information"
+                placeholder="Describe where you found the error"
+                value={value}
+                onChange={syncValue}
+                ref={inputRef}
+                readOnly={readOnly}
+                required={required}
+            />
+        </React.Fragment>
+    );
+}
+
+function DefaultValue({defaultValue}: InputComponentProps) {
+    return (
+        <AdditionalLocationInput
+            value={defaultValue as string}
+            readOnly={true}
+        />
+    );
+}
+
+function NotDefaultValue({defaultValue}: InputComponentProps) {
+    const [tocV, updateTocV] = useState<string | null>();
+    const [addlV, updateAddlV] = useState(defaultValue || '');
+    const required = () => !tocV && !addlV;
+
+    return (
+        <React.Fragment>
+            <TocSelector required={required()} updateValue={updateTocV} />
+            <AdditionalLocationInput
+                value={addlV}
+                required={required()}
+                updateValue={updateAddlV}
+            />
+        </React.Fragment>
+    );
+}
+
+export default function ErrorLocationSelector() {
+    const {searchParams} = useErrataFormContext();
+    const defaultValue = searchParams.get('location');
+    const readOnly = defaultValue && searchParams.get('source');
+    const Input = readOnly ? DefaultValue : NotDefaultValue;
+
+    return <Input defaultValue={defaultValue} />;
+}
diff --git a/src/app/pages/errata-form/form/ErrorLocationSelector/test-data.js b/src/app/pages/errata-form/form/ErrorLocationSelector/test-data.ts
similarity index 100%
rename from src/app/pages/errata-form/form/ErrorLocationSelector/test-data.js
rename to src/app/pages/errata-form/form/ErrorLocationSelector/test-data.ts
diff --git a/src/app/pages/errata-form/form/ErrorLocationSelector/toc-selector.js b/src/app/pages/errata-form/form/ErrorLocationSelector/toc-selector.js
deleted file mode 100644
index d546c290d..000000000
--- a/src/app/pages/errata-form/form/ErrorLocationSelector/toc-selector.js
+++ /dev/null
@@ -1,148 +0,0 @@
-import React, {useState, useRef, useEffect, useMemo} from 'react';
-import useErrataFormContext from '../../errata-form-context';
-import managedInvalidMessage from '../InvalidMessage';
-import bookToc from '~/models/book-toc';
-import {htmlToText} from '~/helpers/data';
-// For LOCAL TESTING when you can't reach Rex; there is another testing section below
-// import testData from './test-data';
-
-function treeEntry(title, indentLevel, parent, isChapter) {
-    const value = parent ? `${parent}:${title}` : title;
-    const expandedValue = value
-        .replace(/(^|:)(\d+ )/, (_, before, num) => `${before}Chapter ${num}`)
-        .replace(/(:)(\d+\.\d+)/, (_, before, num) => `${before}Section ${num}`)
-        .replace(/:(?=\S)/g, ': ');
-
-    return {
-        title,
-        indentLevel,
-        parent,
-        value,
-        expandedValue,
-        isChapter
-    };
-}
-
-function flattenTree(contents, indentLevel=0, parent='') {
-    return contents.map((entry) => {
-        const title = htmlToText(entry.title);
-        const isChapter = Boolean(entry.contents);
-        const thisEntry = treeEntry(title, indentLevel, parent, isChapter);
-
-        return [thisEntry]
-            .concat(entry.contents ? flattenTree(entry.contents, indentLevel+1, thisEntry.value) : []);
-    }).flat();
-}
-
-function ChapterOption({entry, chapterFilter, updateChapterFilter}) {
-    const expanded = chapterFilter === entry.value;
-    const onClick = () => {
-        const value = expanded ? entry.parent : entry.value;
-
-        updateChapterFilter(value);
-    };
-
-    return (
-        <option
-            className="chapter"
-            value={entry.expandedValue}
-            onClick={onClick}
-            aria-expanded={expanded}
-        >
-            {expanded ? '–' : '+'} {entry.title}
-        </option>
-    );
-}
-
-function PageOption({entry}) {
-    return (
-        <option
-            className={`indent-${entry.indentLevel}`}
-            value={entry.expandedValue}
-        >
-            {entry.title}
-        </option>
-    );
-}
-
-function ChapterOrPageOption(passThruOptions) {
-    const {entry} = passThruOptions;
-
-    return (
-        entry.isChapter && !entry.parent ?
-            <ChapterOption {...passThruOptions} /> :
-            <PageOption {...passThruOptions} />
-    );
-}
-
-function useTocTree(slug, chapterFilter) {
-    const [tree, updateTree] = useState([]);
-    const filteredTree = useMemo(
-        () => {
-            if (!chapterFilter) {
-                return tree.filter((entry) => !entry.parent);
-            }
-            return tree.filter((entry) =>
-                !entry.parent ||
-                entry.value.startsWith(chapterFilter));
-        },
-        [tree, chapterFilter]
-    );
-
-    useEffect(() => {
-        if (slug) {
-            bookToc(slug)
-                .then((contents) => updateTree(flattenTree(contents)));
-            // FOR TESTING
-            // .catch(() => {
-            //     console.info('caught...using testdata', testData);
-            //     updateTree(flattenTree(testData.tree.contents));
-            // });
-        }
-    }, [slug]);
-
-    return filteredTree;
-}
-
-export default function TocSelector({required=true, updateValue}) {
-    const {selectedBook} = useErrataFormContext();
-    const inputRef = useRef();
-    const [InvalidMessage, updateInvalidMessage] = managedInvalidMessage(inputRef);
-    const [chapterFilter, updateChapterFilter] = useState();
-    const filteredTree = useTocTree(selectedBook.slug, chapterFilter);
-    const deselect = React.useCallback(
-        () => {
-            inputRef.current.value = null;
-            updateValue(null);
-        },
-        [updateValue]
-    );
-    const onChange = React.useCallback(
-        ({target: {value}}) => updateValue(value),
-        [updateValue]
-    );
-
-    useEffect(updateInvalidMessage, [required, updateInvalidMessage]);
-
-    return (
-        <React.Fragment>
-            <div className="question">Where in the book did you find the error?</div>
-            <InvalidMessage />
-            <select
-                size="10" name="location"
-                ref={inputRef} onChange={onChange}
-                required={required}
-            >
-                {
-                    filteredTree.map((entry, index) =>
-                        <ChapterOrPageOption
-                            key={index}
-                            {...{entry, chapterFilter, updateChapterFilter}}
-                        />
-                    )
-                }
-            </select>
-            <button type="button" className="btn small" onClick={deselect}>Deselect</button>
-        </React.Fragment>
-    );
-}
diff --git a/src/app/pages/errata-form/form/ErrorLocationSelector/toc-selector.tsx b/src/app/pages/errata-form/form/ErrorLocationSelector/toc-selector.tsx
new file mode 100644
index 000000000..529c3b2f0
--- /dev/null
+++ b/src/app/pages/errata-form/form/ErrorLocationSelector/toc-selector.tsx
@@ -0,0 +1,205 @@
+import React, {useState, useRef, useEffect, useMemo} from 'react';
+import useErrataFormContext from '../../errata-form-context';
+import managedInvalidMessage from '../InvalidMessage';
+import bookToc from '~/models/book-toc';
+import {assertNotNull, htmlToText} from '~/helpers/data';
+// For LOCAL TESTING when you can't reach Rex; there is another testing section below
+// import testData from './test-data';
+
+type TreeEntry = {
+    title: string;
+    indentLevel: number;
+    parent: string;
+    value: string;
+    expandedValue: string;
+    isChapter: boolean;
+};
+
+type TocContent = {
+    title: string;
+    contents?: TocContent[];
+};
+
+type ChapterOptionProps = {
+    entry: TreeEntry;
+    chapterFilter: string | undefined;
+    updateChapterFilter: (value: string) => void;
+};
+
+type PageOptionProps = {
+    entry: TreeEntry;
+};
+
+type TocSelectorProps = {
+    required: boolean;
+    updateValue: (value: string | null) => void;
+};
+
+function treeEntry(
+    title: string,
+    indentLevel: number,
+    parent: string,
+    isChapter: boolean
+): TreeEntry {
+    const value = parent ? `${parent}:${title}` : title;
+    const expandedValue = value
+        .replace(/(^|:)(\d+ )/, (_, before, num) => `${before}Chapter ${num}`)
+        .replace(/(:)(\d+\.\d+)/, (_, before, num) => `${before}Section ${num}`)
+        .replace(/:(?=\S)/g, ': ');
+
+    return {
+        title,
+        indentLevel,
+        parent,
+        value,
+        expandedValue,
+        isChapter
+    };
+}
+
+function flattenTree(
+    contents: TocContent[],
+    indentLevel = 0,
+    parent = ''
+): TreeEntry[] {
+    return contents
+        .map((entry) => {
+            const title = htmlToText(entry.title);
+            const isChapter = Boolean(entry.contents);
+            const thisEntry = treeEntry(title, indentLevel, parent, isChapter);
+
+            return [thisEntry].concat(
+                entry.contents
+                    ? flattenTree(
+                          entry.contents,
+                          indentLevel + 1,
+                          thisEntry.value
+                      )
+                    : []
+            );
+        })
+        .flat();
+}
+
+function ChapterOption({
+    entry,
+    chapterFilter,
+    updateChapterFilter
+}: ChapterOptionProps) {
+    const expanded = chapterFilter === entry.value;
+    const onClick = () => {
+        const value = expanded ? entry.parent : entry.value;
+
+        updateChapterFilter(value);
+    };
+
+    return (
+        <option
+            className="chapter"
+            value={entry.expandedValue}
+            onClick={onClick}
+            aria-expanded={expanded}
+        >
+            {expanded ? '–' : '+'} {entry.title}
+        </option>
+    );
+}
+
+function PageOption({entry}: PageOptionProps) {
+    return (
+        <option
+            className={`indent-${entry.indentLevel}`}
+            value={entry.expandedValue}
+        >
+            {entry.title}
+        </option>
+    );
+}
+
+function ChapterOrPageOption(passThruOptions: ChapterOptionProps) {
+    const {entry} = passThruOptions;
+
+    return entry.isChapter && !entry.parent ? (
+        <ChapterOption {...passThruOptions} />
+    ) : (
+        <PageOption {...passThruOptions} />
+    );
+}
+
+function useTocTree(
+    slug: string | undefined,
+    chapterFilter: string | undefined
+) {
+    const [tree, updateTree] = useState<TreeEntry[]>([]);
+    const filteredTree = useMemo(() => {
+        if (!chapterFilter) {
+            return tree.filter((entry) => !entry.parent);
+        }
+        return tree.filter(
+            (entry) => !entry.parent || entry.value.startsWith(chapterFilter)
+        );
+    }, [tree, chapterFilter]);
+
+    useEffect(() => {
+        if (slug) {
+            bookToc(slug).then((contents: TocContent[]) =>
+                updateTree(flattenTree(contents))
+            );
+            // FOR TESTING
+            // .catch(() => {
+            //     console.info('caught...using testdata', testData);
+            //     updateTree(flattenTree(testData.tree.contents));
+            // });
+        }
+    }, [slug]);
+
+    return filteredTree;
+}
+
+export default function TocSelector({required, updateValue}: TocSelectorProps) {
+    const {selectedBook} = useErrataFormContext();
+    const inputRef = useRef<HTMLSelectElement>(null);
+    const [InvalidMessage, updateInvalidMessage] =
+        managedInvalidMessage(inputRef);
+    const [chapterFilter, updateChapterFilter] = useState<string>();
+    const slug = selectedBook ? selectedBook.slug : undefined;
+    const filteredTree = useTocTree(slug, chapterFilter);
+    const deselect = React.useCallback(() => {
+        assertNotNull(inputRef.current).value = '';
+        updateValue(null);
+    }, [updateValue]);
+    const onChange = React.useCallback(
+        ({target: {value}}: React.ChangeEvent<HTMLSelectElement>) =>
+            updateValue(value),
+        [updateValue]
+    );
+
+    useEffect(updateInvalidMessage, [required, updateInvalidMessage]);
+
+    return (
+        <React.Fragment>
+            <label className="question" htmlFor="toc-selector">
+                Where in the book did you find the error?
+            </label>
+            <InvalidMessage />
+            <select
+                id="toc-selector"
+                size={10}
+                name="location"
+                ref={inputRef}
+                onChange={onChange}
+                required={required}
+            >
+                {filteredTree.map((entry, index) => (
+                    <ChapterOrPageOption
+                        key={index}
+                        {...{entry, chapterFilter, updateChapterFilter}}
+                    />
+                ))}
+            </select>
+            <button type="button" className="btn small" onClick={deselect}>
+                Deselect
+            </button>
+        </React.Fragment>
+    );
+}
diff --git a/src/app/pages/errata-form/form/ErrorSourceSelector.js b/src/app/pages/errata-form/form/ErrorSourceSelector.js
deleted file mode 100644
index e68922e98..000000000
--- a/src/app/pages/errata-form/form/ErrorSourceSelector.js
+++ /dev/null
@@ -1,136 +0,0 @@
-import React, {useState, useRef, useMemo} from 'react';
-import useErrataFormContext from '../errata-form-context';
-import managedInvalidMessage from './InvalidMessage';
-import getFields from '~/models/errata-fields';
-
-const sourceNames = {
-};
-
-const resourcePromise = getFields('resources')
-    .then((resources) => resources.map((entry) => entry.field));
-
-function OtherSourceInput() {
-    const inputRef = useRef();
-    const [InvalidMessage, updateInvalidMessage] = managedInvalidMessage(inputRef);
-
-    return (
-        <div className="other-group">
-            <InvalidMessage />
-            <input
-                type="text"
-                name="resource_other" maxLength="250"
-                ref={inputRef} onChange={updateInvalidMessage}
-                required
-            />
-        </div>
-    );
-}
-
-const subnotes = {'Textbook': 'includes print, PDF, and web view'};
-
-function Subnote({sType}) {
-    return (
-        <div className="label-text">
-            {sType}
-            {
-                (sType in subnotes) &&
-                <div className="indented subnote">{subnotes[sType]}</div>
-            }
-        </div>
-    );
-}
-
-function LabeledButton({selectedSource, sType, onChange, radioRef}) {
-    const checked = selectedSource === sType;
-    const showOtherInput = checked && selectedSource === 'Other';
-
-    return (
-        <label>
-            <input
-                type="radio" name="resource"
-                value={sType}
-                defaultChecked={checked}
-                ref={radioRef}
-                onChange={onChange}
-                required
-            />
-            <Subnote sType={sType} />
-            {showOtherInput && <OtherSourceInput />}
-        </label>
-    );
-}
-
-function filterForBook(bookInfo) {
-    // eslint-disable-next-line complexity
-    return function (type) {
-        if (type.startsWith('Assignable')) {
-            return bookInfo.assignable_book;
-        }
-        if (type.startsWith('Kindle')) {
-            return Boolean(bookInfo.kindle_link);
-        }
-        if (type === 'Instructor solution manual') {
-            return bookInfo.book_faculty_resources?.find(
-                (r) => (/^Instructor (Solution|Answer)/).test(r.resource_heading)
-            );
-        }
-        if (type === 'Student solution manual') {
-            return bookInfo.book_student_resources?.find(
-                (r) => (/^Student (Solution|Answer)/).test(r.resource_heading)
-            );
-        }
-        return true;
-    };
-}
-
-function useSourceTypes() {
-    const {searchParams, selectedBook} = useErrataFormContext();
-    const source = searchParams.get('source');
-    const initialSource = source && sourceNames[source.toLowerCase()];
-    const [sourceTypes, updateSourceTypes] = useState([]);
-    const filteredSourceTypes = useMemo(
-        () => sourceTypes.filter(filterForBook(selectedBook)),
-        [sourceTypes, selectedBook]
-    );
-    const [selectedSource, updateSelectedSource] = useState(initialSource);
-    const onChange = React.useCallback(
-        ({target: {value}}) => updateSelectedSource(value),
-        []
-    );
-
-    React.useEffect(
-        () => resourcePromise.then(updateSourceTypes),
-        [selectedBook]
-    );
-
-    return {sourceTypes: filteredSourceTypes, selectedSource, onChange};
-}
-
-export default function ErrorSourceSelector() {
-    const radioRef = useRef();
-    const {sourceTypes, onChange, selectedSource} = useSourceTypes();
-    const [RadioInvalidMessage, updateRadioInvalidMessage] = managedInvalidMessage(radioRef);
-
-    React.useEffect(
-        updateRadioInvalidMessage,
-        [sourceTypes, selectedSource, updateRadioInvalidMessage]
-    );
-
-    return (
-        <React.Fragment>
-            <div className="question">In which source did you find this error?</div>
-            <div className="radio-columns">
-                <RadioInvalidMessage />
-                {
-                    sourceTypes.map((sType, index) => (
-                        <LabeledButton
-                            key={sType}
-                            sType={sType} selectedSource={selectedSource}
-                            onChange={onChange} radioRef={index === 0 ? radioRef : null}
-                        />
-                    ))
-                }
-            </div>
-        </React.Fragment>
-    );
-}
diff --git a/src/app/pages/errata-form/form/ErrorSourceSelector.tsx b/src/app/pages/errata-form/form/ErrorSourceSelector.tsx
new file mode 100644
index 000000000..dc5c64143
--- /dev/null
+++ b/src/app/pages/errata-form/form/ErrorSourceSelector.tsx
@@ -0,0 +1,156 @@
+import React, {useState, useRef, useMemo} from 'react';
+import useErrataFormContext from '../errata-form-context';
+import {type Book} from '~/helpers/books';
+import managedInvalidMessage from './InvalidMessage';
+import getFields from '~/models/errata-fields';
+
+type SourceSelectorProps = {
+    selectedSource: string | null;
+    sType: string;
+    onChange: (event: React.ChangeEvent<HTMLInputElement>) => void;
+    radioRef?: React.RefObject<HTMLInputElement>;
+};
+
+type SubnoteProps = {
+    sType: string;
+};
+
+const resourcePromise = getFields('resources').then(
+    (resources: {field: string}[]) => resources.map((entry) => entry.field)
+);
+
+function OtherSourceInput() {
+    const inputRef = useRef<HTMLInputElement>(null);
+    const [InvalidMessage, updateInvalidMessage] =
+        managedInvalidMessage(inputRef);
+
+    return (
+        <div className="other-group">
+            <InvalidMessage />
+            <input
+                type="text"
+                name="resource_other"
+                maxLength={250}
+                ref={inputRef}
+                onChange={updateInvalidMessage}
+                required
+                aria-label="other source"
+            />
+        </div>
+    );
+}
+
+const subnotes: Record<string, string> = {
+    Textbook: 'includes print, PDF, and web view'
+};
+
+function Subnote({sType}: SubnoteProps) {
+    return (
+        <div className="label-text">
+            {sType}
+            {sType in subnotes && (
+                <div className="indented subnote">{subnotes[sType]}</div>
+            )}
+        </div>
+    );
+}
+
+function LabeledButton({
+    selectedSource,
+    sType,
+    onChange,
+    radioRef
+}: SourceSelectorProps) {
+    const checked = selectedSource === sType;
+    const showOtherInput = checked && selectedSource === 'Other';
+
+    return (
+        <label>
+            <input
+                type="radio"
+                name="resource"
+                value={sType}
+                defaultChecked={checked}
+                ref={radioRef}
+                onChange={onChange}
+                required
+            />
+            <Subnote sType={sType} />
+            {showOtherInput && <OtherSourceInput />}
+        </label>
+    );
+}
+
+function filterForBook(bookInfo: Book) {
+    return function (type: string) {
+        if (type.startsWith('Assignable')) {
+            return bookInfo.assignable_book;
+        }
+        if (type.startsWith('Kindle')) {
+            return Boolean(bookInfo.kindle_link);
+        }
+        if (type === 'Instructor solution manual') {
+            return bookInfo.has_faculty_resources;
+        }
+        if (type === 'Student solution manual') {
+            return bookInfo.has_student_resources;
+        }
+        return true;
+    };
+}
+
+function useSourceTypes() {
+    const {selectedBook} = useErrataFormContext();
+    const [sourceTypes, updateSourceTypes] = useState<string[]>([]);
+    const filteredSourceTypes = useMemo(
+        () => sourceTypes.filter(filterForBook(selectedBook ?? ({} as Book))),
+        [sourceTypes, selectedBook]
+    );
+    const [selectedSource, updateSelectedSource] = useState<string | null>(
+        null
+    );
+    const onChange = React.useCallback(
+        ({target: {value}}: React.ChangeEvent<HTMLInputElement>) =>
+            updateSelectedSource(value),
+        []
+    );
+
+    React.useEffect(() => {
+        resourcePromise.then(updateSourceTypes);
+    }, [selectedBook]);
+
+    return {sourceTypes: filteredSourceTypes, selectedSource, onChange};
+}
+
+export default function ErrorSourceSelector() {
+    const radioRef = useRef<HTMLInputElement>(null);
+    const {sourceTypes, onChange, selectedSource} = useSourceTypes();
+    const [RadioInvalidMessage, updateRadioInvalidMessage] =
+        managedInvalidMessage(radioRef);
+
+    React.useEffect(updateRadioInvalidMessage, [
+        sourceTypes,
+        selectedSource,
+        updateRadioInvalidMessage
+    ]);
+
+    return (
+        <React.Fragment>
+            <div className="question">
+                In which source did you find this error?
+            </div>
+            <fieldset className="radio-columns">
+                <RadioInvalidMessage />
+                {sourceTypes.map((sType, index) => (
+                    <LabeledButton
+                        key={sType}
+                        sType={sType}
+                        selectedSource={selectedSource}
+                        onChange={onChange}
+                        radioRef={index === 0 ? radioRef : undefined}
+                    />
+                ))}
+            </fieldset>
+        </React.Fragment>
+    );
+}
diff --git a/src/app/pages/errata-form/form/ErrorTypeSelector.js b/src/app/pages/errata-form/form/ErrorTypeSelector.js
deleted file mode 100644
index 6efcc195b..000000000
--- a/src/app/pages/errata-form/form/ErrorTypeSelector.js
+++ /dev/null
@@ -1,74 +0,0 @@
-import React, {useState, useRef} from 'react';
-import managedInvalidMessage from './InvalidMessage';
-
-function OtherErrorInput() {
-    const inputRef = useRef();
-    const [InvalidMessage, updateInvalidMessage] = managedInvalidMessage(inputRef);
-
-    return (
-        <div className="other-group">
-            <InvalidMessage />
-            <input
-                type="text"
-                name="error_type_other"
-                maxLength="250"
-                ref={inputRef}
-                onChange={updateInvalidMessage}
-                required
-            />
-        </div>
-    );
-}
-
-export default function ErrorTypeSelector() {
-    const errorTypes = [
-        'Broken link',
-        'Incorrect answer, calculation, or solution',
-        'General/pedagogical suggestion or question',
-        'Other factual inaccuracy in content',
-        'Typo',
-        'Other'
-    ];
-    const inputRef = useRef();
-    const [InvalidMessage, updateInvalidMessage] = managedInvalidMessage(inputRef);
-    const [selectedError, updateSelectedError] = useState();
-    const helpBoxVisible = selectedError === 'Other' ? 'visible' : 'not-visible';
-    const onChange = React.useCallback(
-        (event) => {
-            updateSelectedError(event.target.value);
-            updateInvalidMessage();
-        },
-        [updateSelectedError, updateInvalidMessage]
-    );
-
-    return (
-        <React.Fragment>
-            <div className="question">Select the type of error below.</div>
-            <div className="radio-columns">
-                <InvalidMessage />
-                {
-                    errorTypes.map((eType) =>
-                        <label key={eType}>
-                            <input
-                                type="radio" name="error_type" value={eType}
-                                ref={inputRef}
-                                onChange={onChange}
-                                required
-                            />
-                            <span className="label-text">{eType}</span>
-                            {
-                                (eType === 'Other' && selectedError === 'Other') && (
-                                    <OtherErrorInput />
-                                )
-                            }
-                        </label>
-                    )
-                }
-            </div>
-            <div className={`helpbox ${helpBoxVisible}`}>
-                <span>Need help logging in or have general questions? Contact Support at </span>
-                <a href="mailto:support@openstax.org">support@openstax.org</a>.
-            </div>
-        </React.Fragment>
-    );
-}
diff --git a/src/app/pages/errata-form/form/ErrorTypeSelector.tsx b/src/app/pages/errata-form/form/ErrorTypeSelector.tsx
new file mode 100644
index 000000000..b8e1b0869
--- /dev/null
+++ b/src/app/pages/errata-form/form/ErrorTypeSelector.tsx
@@ -0,0 +1,79 @@
+import React, {useState, useRef} from 'react';
+import managedInvalidMessage from './InvalidMessage';
+
+function OtherErrorInput() {
+    const inputRef = useRef<HTMLInputElement>(null);
+    const [InvalidMessage, updateInvalidMessage] =
+        managedInvalidMessage(inputRef);
+
+    return (
+        <div className="other-group">
+            <InvalidMessage />
+            <input
+                type="text"
+                name="error_type_other"
+                aria-label="other error type"
+                maxLength={250}
+                ref={inputRef}
+                onChange={updateInvalidMessage}
+                required
+            />
+        </div>
+    );
+}
+
+export default function ErrorTypeSelector() {
+    const errorTypes = [
+        'Broken link',
+        'Incorrect answer, calculation, or solution',
+        'General/pedagogical suggestion or question',
+        'Other factual inaccuracy in content',
+        'Typo',
+        'Other'
+    ];
+    const inputRef = useRef<HTMLInputElement>(null);
+    const [InvalidMessage, updateInvalidMessage] =
+        managedInvalidMessage(inputRef);
+    const [selectedError, updateSelectedError] = useState<string>();
+    const helpBoxVisible =
+        selectedError === 'Other' ? 'visible' : 'not-visible';
+    const onChange = React.useCallback(
+        (event: React.ChangeEvent<HTMLInputElement>) => {
+            updateSelectedError(event.target.value);
+            updateInvalidMessage();
+        },
+        [updateSelectedError, updateInvalidMessage]
+    );
+
+    return (
+        <React.Fragment>
+            <div className="question">Select the type of error below.</div>
+            <fieldset className="radio-columns">
+                <InvalidMessage />
+                {errorTypes.map((eType) => (
+                    <label key={eType}>
+                        <input
+                            type="radio"
+                            name="error_type"
+                            value={eType}
+                            ref={inputRef}
+                            onChange={onChange}
+                            required
+                        />
+                        <span className="label-text">{eType}</span>
+                        {eType === 'Other' && selectedError === 'Other' && (
+                            <OtherErrorInput />
+                        )}
+                    </label>
+                ))}
+            </fieldset>
+            <div className={`helpbox ${helpBoxVisible}`}>
+                <span>
+                    Need help logging in or have general questions? Contact
+                    Support at{' '}
+                </span>
+                <a href="mailto:support@openstax.org">support@openstax.org</a>.
+            </div>
+        </React.Fragment>
+    );
+}
diff --git a/src/app/pages/errata-form/form/FileUploader.js b/src/app/pages/errata-form/form/FileUploader.tsx
similarity index 53%
rename from src/app/pages/errata-form/form/FileUploader.js
rename to src/app/pages/errata-form/form/FileUploader.tsx
index ee9f3bdc8..4aadcc23b 100644
--- a/src/app/pages/errata-form/form/FileUploader.js
+++ b/src/app/pages/errata-form/form/FileUploader.tsx
@@ -3,11 +3,15 @@ import {FontAwesomeIcon} from '@fortawesome/react-fontawesome';
 import {faTimes} from '@fortawesome/free-solid-svg-icons/faTimes';
 import cn from 'classnames';
 
-export function FileButton({name}) {
+type FileButtonProps = {
+    name: string;
+};
+
+export function FileButton({name}: FileButtonProps) {
     const [filePath, updateFilePath] = useState('');
     const empty = filePath === '';
 
-    function setFile(event) {
+    function setFile(event: React.ChangeEvent<HTMLInputElement>) {
         updateFilePath(event.target.value.replace(/.*\\/, ''));
     }
 
@@ -26,19 +30,28 @@ export function FileButton({name}) {
 
     return (
         <div className={cn('file-button', {empty})}>
-            <label className="btn" role="button" tabIndex="0">
+            <label className="btn" role="button" tabIndex={0}>
                 {filePath ? 'Change' : 'Add file'}
-                <input type="file" className="hidden" name={name} onChange={setFile} />
+                <input
+                    type="file"
+                    className="hidden"
+                    name={name}
+                    onChange={setFile}
+                />
             </label>
-            {
-                filePath &&
-                    <React.Fragment>
-                        <span className="file-name">{filePath}</span>
-                        <button type="button" className="clear-file" aria-label="Clear file" onClick={clearFile}>
-                            <FontAwesomeIcon icon={faTimes} />
-                        </button>
-                    </React.Fragment>
-            }
+            {filePath && (
+                <React.Fragment>
+                    <span className="file-name">{filePath}</span>
+                    <button
+                        type="button"
+                        className="clear-file"
+                        aria-label="Clear file"
+                        onClick={clearFile}
+                    >
+                        <FontAwesomeIcon icon={faTimes} />
+                    </button>
+                </React.Fragment>
+            )}
         </div>
     );
 }
diff --git a/src/app/pages/errata-form/form/InvalidMessage.js b/src/app/pages/errata-form/form/InvalidMessage.tsx
similarity index 56%
rename from src/app/pages/errata-form/form/InvalidMessage.js
rename to src/app/pages/errata-form/form/InvalidMessage.tsx
index 2293c24ce..060324251 100644
--- a/src/app/pages/errata-form/form/InvalidMessage.js
+++ b/src/app/pages/errata-form/form/InvalidMessage.tsx
@@ -7,26 +7,27 @@ import React, {useState, useEffect} from 'react';
  * It is important that the ref item exist when the message item is created
  */
 
-function InvalidMessage({message}) {
-    return (
-        <span className="invalid-message">{message}</span>
-    );
+type InvalidMessageProps = {
+    message: string;
+};
+
+function InvalidMessage({message}: InvalidMessageProps) {
+    return <span className="invalid-message">{message}</span>;
 }
 
-export default function (inputRef) {
+export default function (
+    inputRef: React.RefObject<
+        HTMLInputElement | HTMLTextAreaElement | HTMLSelectElement
+    >
+): [() => React.JSX.Element, () => void] {
     const [message, updateMessage] = useState('');
     const updateFromRef = () => {
         if (inputRef.current) {
             updateMessage(inputRef.current.validationMessage);
-        } else {
-            console.warn('No current ref', inputRef);
         }
     };
 
     useEffect(updateFromRef, [inputRef]);
 
-    return [
-        () => <InvalidMessage message={message} />,
-        updateFromRef
-    ];
+    return [() => <InvalidMessage message={message} />, updateFromRef];
 }
diff --git a/src/app/pages/errata-form/form/form.scss b/src/app/pages/errata-form/form/form.scss
index 65e7f6398..4b1d7bebf 100644
--- a/src/app/pages/errata-form/form/form.scss
+++ b/src/app/pages/errata-form/form/form.scss
@@ -41,7 +41,7 @@
         color: text-color(helper);
     }
 
-    label {
+    label:not(.question) {
         align-items: center;
         color: text-color(helper);
         display: flex;
diff --git a/src/app/pages/errata-form/form/form.js b/src/app/pages/errata-form/form/form.tsx
similarity index 60%
rename from src/app/pages/errata-form/form/form.js
rename to src/app/pages/errata-form/form/form.tsx
index 049b645d0..e29912bbc 100644
--- a/src/app/pages/errata-form/form/form.js
+++ b/src/app/pages/errata-form/form/form.tsx
@@ -12,44 +12,61 @@ import {useNavigate} from 'react-router-dom';
 import cn from 'classnames';
 import './form.scss';
 
+type ApiResponse = {
+    id?: string;
+    submitted_by_account_id?: string[];
+};
+
 const postEndpoint = `${$.apiOriginAndOldPrefix}/errata/`;
 
 function ErrorExplanationBox() {
-    const inputRef = useRef();
-    const [InvalidMessage, updateInvalidMessage] = managedInvalidMessage(inputRef);
+    const inputRef = useRef<HTMLTextAreaElement>(null);
+    const [InvalidMessage, updateInvalidMessage] =
+        managedInvalidMessage(inputRef);
 
     return (
         <React.Fragment>
-            <div className="question">Tell us in detail about the error and your suggestion.</div>
+            <label className="question" htmlFor="error-detail">
+                Tell us in detail about the error and your suggestion.
+            </label>
             <div className="subnote wide">
                 Please limit to one error per submission and include a suggested
                 resolution if possible. If you have several to report, please
-                contact us at <a href="mailto:errata@openstax.org">errata@openstax.org</a>.
+                contact us at{' '}
+                <a href="mailto:errata@openstax.org">errata@openstax.org</a>.
             </div>
             <InvalidMessage />
             <textarea
-                maxLength="4000" name="detail"
-                ref={inputRef} onChange={updateInvalidMessage}
-                required></textarea>
+                id="error-detail"
+                maxLength={4000}
+                name="detail"
+                ref={inputRef}
+                onChange={updateInvalidMessage}
+                required
+            ></textarea>
         </React.Fragment>
     );
 }
 
 function SubmitButton() {
-    const {hasError, submitting, validateBeforeSubmitting} = useErrataFormContext();
+    const {hasError, submitting, validateBeforeSubmitting} =
+        useErrataFormContext();
 
     return (
         <div className="submit-button">
             <input
-                type="submit" className="btn" value="Submit"
-                disabled={submitting} onClick={validateBeforeSubmitting}
+                type="submit"
+                className="btn"
+                value="Submit"
+                disabled={submitting}
+                onClick={validateBeforeSubmitting}
             />
             {hasError && <div className="invalid-message">{hasError}</div>}
         </div>
     );
 }
 
-const semesters = [
+const semesters: [string, string, string][] = [
     ['March', 'October', 'spring'],
     ['November', 'February', 'fall']
 ];
@@ -61,12 +78,12 @@ function RevisionSchedule() {
 
     return (
         <div className="revision-schedule">
-            Errata received from <b>{start}</b> through <b>{end}</b> will be fixed
-            in the online format for the <b>{semester}</b> semester.
+            Errata received from <b>{start}</b> through <b>{end}</b> will be
+            fixed in the online format for the <b>{semester}</b> semester.
             <br />
-            PDF versions of OpenStax textbooks are only updated once a year, prior
-            to the fall semester, if there are substantial errata updates to the
-            book that year.
+            PDF versions of OpenStax textbooks are only updated once a year,
+            prior to the fall semester, if there are substantial errata updates
+            to the book that year.
         </div>
     );
 }
@@ -74,16 +91,24 @@ function RevisionSchedule() {
 function FormFields() {
     const {selectedBook} = useErrataFormContext();
     const {accountId: submittedBy} = useUserContext();
+    const id = selectedBook ? selectedBook.id : '';
 
     return (
         <React.Fragment>
-            <input type="hidden" name="submitted_by_account_id" value={submittedBy} />
-            <input type="hidden" name="book" value={selectedBook.id} />
+            <input
+                type="hidden"
+                name="submitted_by_account_id"
+                value={submittedBy}
+            />
+            <input type="hidden" name="book" value={id} />
             <ErrorTypeSelector />
             <ErrorSourceSelector />
             <ErrorLocationSelector />
             <ErrorExplanationBox />
-            <div className="question">Please add a screenshot or any other file that helps explain the error.</div>
+            <div className="question">
+                Please add a screenshot or any other file that helps explain the
+                error.
+            </div>
             <div className="button-group">
                 <FileUploader />
                 <SubmitButton />
@@ -95,32 +120,34 @@ function FormFields() {
 
 // Safari cannot handle empty files; Edge cannot manipulate FormData
 // so we remove the file inputs that have no values
-function removeEmptyFileWidgets(formEl) {
-    const fileInputs = Array.from(formEl.querySelectorAll('[type="file"]'));
+function removeEmptyFileWidgets(formEl: HTMLFormElement) {
+    const fileInputs = Array.from(
+        formEl.querySelectorAll<HTMLInputElement>('[type="file"]')
+    );
     const fiParents = fileInputs.map((el) => el.parentNode);
 
     fileInputs.forEach((el) => {
         if (el.value === '') {
-            el.parentNode.removeChild(el);
+            el.parentNode?.removeChild(el);
         }
     });
     fileInputs.forEach((el, index) => {
-        el.setAttribute('name', `file_${index+1}`);
+        el.setAttribute('name', `file_${index + 1}`);
     });
 
     // Return a function to put them back
     return () => {
         fileInputs.forEach((el, i) => {
-            fiParents[i].appendChild(el);
+            fiParents[i]?.appendChild(el);
         });
     };
 }
 
 function useBannedDialog() {
-    const [bannedText, setBannedText] = useState();
+    const [bannedText, setBannedText] = useState<string>();
     const navigate = useNavigate();
     const handleSubmissionResponse = React.useCallback(
-        (json) => {
+        (json: ApiResponse) => {
             if (json.id) {
                 navigate(`/confirmation/errata?id=${json.id}`);
             } else if (json.submitted_by_account_id) {
@@ -141,7 +168,8 @@ function useBannedDialog() {
     function BannedDialog() {
         return (
             <Dialog
-                isOpen={bannedText} onPutAway={() => setBannedText(null)}
+                isOpen={Boolean(bannedText)}
+                onPutAway={() => setBannedText(undefined)}
                 title="Errata submission rejected"
             >
                 <div className="banned-notice">{bannedText}</div>
@@ -149,44 +177,39 @@ function useBannedDialog() {
         );
     }
 
-    return [BannedDialog, handleSubmissionResponse];
+    return [BannedDialog, handleSubmissionResponse] as const;
 }
 
 export default function ErrataForm() {
     const {hideErrors, submitting, setHasError} = useErrataFormContext();
     const [BannedDialog, handleSubmissionResponse] = useBannedDialog();
-    const formRef = useRef();
+    const formRef = useRef<HTMLFormElement>(null);
 
     function validate() {
-        const invalid = formRef.current.querySelector(':invalid');
+        const invalid = formRef.current?.querySelector<HTMLElement>(':invalid');
 
         setHasError(invalid ? 'You have not completed the form.' : null);
     }
 
     React.useEffect(() => {
-        if (submitting) {
+        if (submitting && formRef.current) {
             const formEl = formRef.current;
             const putFileWidgetsBack = removeEmptyFileWidgets(formEl);
             const formData = new window.FormData(formEl);
 
             // Programmatically post the form
-            fetch(
-                postEndpoint,
-                {
-                    method: 'POST',
-                    body: formData
-                }
-            )
+            fetch(postEndpoint, {
+                method: 'POST',
+                body: formData
+            })
                 .then((r) => r.json())
-                .catch((err) => {throw new Error(`Posting errata form data: ${err}`);})
-                .then(
-                    handleSubmissionResponse,
-                    (fetchError) => {
-                        setHasError(`Submit failed: ${fetchError}.`);
-                        putFileWidgetsBack();
-                    }
-                )
-            ;
+                .catch((err) => {
+                    throw new Error(`Posting errata form data: ${err}`);
+                })
+                .then(handleSubmissionResponse, (fetchError: Error) => {
+                    setHasError(`Submit failed: ${fetchError}.`);
+                    putFileWidgetsBack();
+                });
         }
     }, [submitting, setHasError, handleSubmissionResponse]);
 
@@ -194,10 +217,12 @@ export default function ErrataForm() {
         <React.Fragment>
             <form
                 className={cn('body-block', {'hide-errors': hideErrors})}
-                method="post" action={postEndpoint}
+                method="post"
+                action={postEndpoint}
                 encType="multipart/form-data"
                 onChange={validate}
                 ref={formRef}
+                name="errata-form"
             >
                 <FormFields />
             </form>
diff --git a/test/helpers/fetch-mocker.js b/test/helpers/fetch-mocker.js
index e9601677d..172859fe6 100644
--- a/test/helpers/fetch-mocker.js
+++ b/test/helpers/fetch-mocker.js
@@ -34,6 +34,7 @@ import pressData from '../src/data/press';
 import pressArticleData from '../src/data/press-article';
 import researchData from '../src/data/research';
 import renewalData from '../src/data/renewal';
+import resourcesData from '../src/data/resources';
 import rolesData from '../src/data/roles';
 import salesforceData from '../src/data/salesforce';
 import salesforcePartnerData from '../src/data/salesforce-partners';
@@ -52,7 +53,8 @@ import archiveData from '../src/data/archive';
 // eslint-disable-next-line no-undef
 global.fetch = jest.fn().mockImplementation((...args) => {
     const isAdoption = (/pages\/adoption-form/).test(args[0]);
-    const isAlgebra = (/v2\/pages\/39/).test(args[0]);
+    // 81 is Astronomy, but we don't much care what the content is
+    const isAlgebra = (/v2\/pages\/(39|81)/).test(args[0]);
     const isAllBooks = (/book_subjects/).test(args[0]);
     const isAmazonBlurb = args[0].endsWith('snippets/amazonbookblurb/');
     const isBiology = (/v2\/pages\/207/).test(args[0]);
@@ -90,6 +92,7 @@ global.fetch = jest.fn().mockImplementation((...args) => {
     const isPressArticle = (/api\/press\/[a-z]/).test(args[0]);
     const isRenewal = args[0].includes('renewal?account_uuid');
     const isResearch = args[0].includes('pages/research');
+    const isResources = args[0].endsWith('errata-fields/?field=resources');
     const isRoles = (/snippets\/roles/).test(args[0]);
     const isSchools = (/salesforce\/schools/).test(args[0]);
     const isSearchCollection = args[0].includes('/search/?collection=');
@@ -186,6 +189,8 @@ global.fetch = jest.fn().mockImplementation((...args) => {
                 payload = booksForAnalyticsData;
             } else if (isRenewal) {
                 payload = renewalData;
+            } else if (isResources) {
+                payload = resourcesData;
             } else if (isRoles) {
                 payload = rolesData;
             } else if (isSchools) {
diff --git a/test/src/data/astronomy-toc.json b/test/src/data/astronomy-toc.json
new file mode 100644
index 000000000..7376a8900
--- /dev/null
+++ b/test/src/data/astronomy-toc.json
@@ -0,0 +1,3323 @@
+{
+  "title": "Astronomy 2e",
+  "revised": "2025-07-16T14:51:35+00:00",
+  "tree": {
+    "id": "4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6",
+    "title": "Astronomy 2e",
+    "contents": [
+      {
+        "id": "b795b4f7-3318-4419-a338-8f5eeb0874ee@",
+        "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Preface</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "preface",
+        "slug": "preface"
+      },
+      {
+        "id": "7a834c01-a9a2-5697-a1cf-0f59df8b56ca@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>1</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Science and the Universe: A Brief Tour</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "ff8e6ee8-8a50-4756-b95e-c3b8e803622b@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Introduction</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "1-introduction"
+          },
+          {
+            "id": "7f11b6c9-3774-45f2-89e7-65c0196f6c29@",
+            "title": "<span class=\"os-number\">1.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nature of Astronomy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-1-the-nature-of-astronomy"
+          },
+          {
+            "id": "c2150b0b-4881-42c7-83b2-ad766c79d36a@",
+            "title": "<span class=\"os-number\">1.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nature of Science</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-2-the-nature-of-science"
+          },
+          {
+            "id": "8b5ce726-e912-4fcd-aacf-e35aaafb9839@",
+            "title": "<span class=\"os-number\">1.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Laws of Nature</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-3-the-laws-of-nature"
+          },
+          {
+            "id": "6d1abd05-a7d8-44c0-acd0-b5b97b3f771b@",
+            "title": "<span class=\"os-number\">1.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Numbers in Astronomy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-4-numbers-in-astronomy"
+          },
+          {
+            "id": "72f7108d-f806-4f54-80ac-eed5976266e2@",
+            "title": "<span class=\"os-number\">1.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Consequences of Light Travel Time</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-5-consequences-of-light-travel-time"
+          },
+          {
+            "id": "206e426a-3d8f-4832-80dd-189b03869a34@",
+            "title": "<span class=\"os-number\">1.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Tour of the Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-6-a-tour-of-the-universe"
+          },
+          {
+            "id": "abd4b491-1fd8-418f-8a46-c0c9f96df944@",
+            "title": "<span class=\"os-number\">1.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Universe on the Large Scale</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-7-the-universe-on-the-large-scale"
+          },
+          {
+            "id": "15fa90be-da2d-48d6-bae9-f3b84d1d3960@",
+            "title": "<span class=\"os-number\">1.8</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Universe of the Very Small</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-8-the-universe-of-the-very-small"
+          },
+          {
+            "id": "bc9a9cec-f111-457a-8360-f3dfcdbfa410@",
+            "title": "<span class=\"os-number\">1.9</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Conclusion and a Beginning</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "1-9-a-conclusion-and-a-beginning"
+          },
+          {
+            "id": "b509e547-2c22-5620-9896-032cf5ffd458@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "1-for-further-exploration"
+          }
+        ],
+        "slug": "1-science-and-the-universe-a-brief-tour"
+      },
+      {
+        "id": "e56bf2dc-f872-57c9-865a-8442ca8ebe0e@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>2</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Observing the Sky: The Birth of Astronomy</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "5669c796-2b05-4a8f-96ac-85939b9b32af@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "2-thinking-ahead"
+          },
+          {
+            "id": "8c5081ca-2ce9-44b9-8491-bfa4d6948d6e@",
+            "title": "<span class=\"os-number\">2.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Sky Above</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "2-1-the-sky-above"
+          },
+          {
+            "id": "3eb6f7c7-5832-4824-b71b-2fa5c5859cb6@",
+            "title": "<span class=\"os-number\">2.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Ancient Astronomy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "2-2-ancient-astronomy"
+          },
+          {
+            "id": "3e7849d9-bda2-4f03-8517-953f63735a69@",
+            "title": "<span class=\"os-number\">2.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Astrology and Astronomy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "2-3-astrology-and-astronomy"
+          },
+          {
+            "id": "0fa12f98-6991-469f-9e81-e518d4b1507b@",
+            "title": "<span class=\"os-number\">2.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Birth of Modern Astronomy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "2-4-the-birth-of-modern-astronomy"
+          },
+          {
+            "id": "1d5e084d-726a-5f29-90e3-b8320f12a954@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "2-key-terms"
+          },
+          {
+            "id": "d12fe360-e8e0-5690-af42-30f17b29cb3d@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "2-summary"
+          },
+          {
+            "id": "e24ee7bd-d21b-5af6-a665-f2934ef40c38@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "2-for-further-exploration"
+          },
+          {
+            "id": "e5b6912f-7333-57c8-b7af-c93673a27487@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "2-collaborative-group-activities"
+          },
+          {
+            "id": "c26fda6f-94bf-5036-90c8-172398909927@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "bf884580-f8b4-5cac-83be-71d8be3b7a38@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "2-review-questions"
+              },
+              {
+                "id": "942be1a5-3d38-5106-9294-bc821ded82f7@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "2-thought-questions"
+              },
+              {
+                "id": "b54556fb-cfc3-5575-ac76-78f763cde267@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "2-figuring-for-yourself"
+              }
+            ],
+            "slug": "2-exercises"
+          }
+        ],
+        "slug": "2-observing-the-sky-the-birth-of-astronomy"
+      },
+      {
+        "id": "fe49f25b-bf43-577a-b1f0-2efb1830b6c5@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>3</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Orbits and Gravity</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "e2171dce-08e7-4d5d-9f87-ae6d454b6831@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "3-thinking-ahead"
+          },
+          {
+            "id": "47523a07-81ed-49ea-907c-775a77830d8f@",
+            "title": "<span class=\"os-number\">3.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Laws of Planetary Motion</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "3-1-the-laws-of-planetary-motion"
+          },
+          {
+            "id": "8dc7024f-0626-4a47-9ddb-34ecd15db2f6@",
+            "title": "<span class=\"os-number\">3.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Newton’s Great Synthesis</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "3-2-newtons-great-synthesis"
+          },
+          {
+            "id": "b601e378-6e52-49c0-a085-29e17a7763bc@",
+            "title": "<span class=\"os-number\">3.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Newton’s Universal Law of Gravitation</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "3-3-newtons-universal-law-of-gravitation"
+          },
+          {
+            "id": "e2c6b1d7-f6ec-4586-9648-770769fb9b34@",
+            "title": "<span class=\"os-number\">3.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Orbits in the Solar System</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "3-4-orbits-in-the-solar-system"
+          },
+          {
+            "id": "b5a9fa3d-f23f-4c86-9ed9-50bfc39fd05b@",
+            "title": "<span class=\"os-number\">3.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Motions of Satellites and Spacecraft</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "3-5-motions-of-satellites-and-spacecraft"
+          },
+          {
+            "id": "2b0e50b7-cacc-4a71-8f1b-6b3151fa8219@",
+            "title": "<span class=\"os-number\">3.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Gravity with More Than Two Bodies</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "3-6-gravity-with-more-than-two-bodies"
+          },
+          {
+            "id": "4848f68c-234e-56ef-af32-f32662b23a3f@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "3-key-terms"
+          },
+          {
+            "id": "6a236ece-02df-53bd-89a7-f1dd3c3a69db@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "3-summary"
+          },
+          {
+            "id": "e7f667c6-c2fd-543b-88b4-0d0d04254e96@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "3-for-further-exploration"
+          },
+          {
+            "id": "281cb692-f479-53cf-a654-25fa863a0e37@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "3-collaborative-group-activities"
+          },
+          {
+            "id": "67310f45-7bc0-5fa1-a043-cd9404ebb711@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "189047a9-c2a9-5cc6-9b4c-13b792ee0a48@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "3-review-questions"
+              },
+              {
+                "id": "1154892f-55a9-5e47-8080-6a7916fb2b0f@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "3-thought-questions"
+              },
+              {
+                "id": "f306f90d-c4ce-57f2-9e85-9c65c99eefa3@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "3-figuring-for-yourself"
+              }
+            ],
+            "slug": "3-exercises"
+          }
+        ],
+        "slug": "3-orbits-and-gravity"
+      },
+      {
+        "id": "394032b3-ade7-5a91-b373-7a7bb9da439d@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>4</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Earth, Moon, and Sky</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "1620756f-04bc-4173-b549-e693ce6e573f@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "4-thinking-ahead"
+          },
+          {
+            "id": "2137756f-bba9-4571-b15d-d99af6911ce8@",
+            "title": "<span class=\"os-number\">4.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Earth and Sky</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "4-1-earth-and-sky"
+          },
+          {
+            "id": "1fa4ebbd-7de6-4b35-8b96-1ea6538d10f7@",
+            "title": "<span class=\"os-number\">4.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Seasons</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "4-2-the-seasons"
+          },
+          {
+            "id": "ff0d0421-83f7-42ce-a604-e3820ebafd76@",
+            "title": "<span class=\"os-number\">4.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Keeping Time</span>",
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+            "title": "<span class=\"os-number\">4.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Phases and Motions of the Moon</span>",
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+            "title": "<span class=\"os-number\">4.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Ocean Tides and the Moon</span>",
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+            "title": "<span class=\"os-number\">4.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Eclipses of the Sun and Moon</span>",
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+                "id": "19efc8be-1fef-5e02-837d-a59b2da0f3b1@24525b6",
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+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>5</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Radiation and Spectra</span>",
+        "toc_type": "chapter",
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+            "id": "bc5ce180-f2b3-4469-a882-22bf96435c99@",
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+            "toc_type": "book-content",
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+            "slug": "5-3-spectroscopy-in-astronomy"
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+            "title": "<span class=\"os-number\">5.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Structure of the Atom</span>",
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+            "title": "<span class=\"os-number\">5.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Formation of Spectral Lines</span>",
+            "toc_type": "book-content",
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+            "title": "<span class=\"os-number\">5.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Doppler Effect</span>",
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+            "id": "ac348c37-facc-5204-9ea3-33f8360a2641@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
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+                "id": "9fbdcef4-4417-5477-b51b-dded5adedc8a@24525b6",
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+                "toc_type": "book-content",
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+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>6</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Astronomical Instruments</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "bd9d6fca-fd83-4112-9379-482f40364ae7@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
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+            "id": "7c547388-eced-47de-80c9-4826b072356e@",
+            "title": "<span class=\"os-number\">6.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Telescopes</span>",
+            "toc_type": "book-content",
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+            "slug": "6-1-telescopes"
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+          {
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+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
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+            "toc_type": "book-content",
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+            "slug": "6-3-visible-light-detectors-and-instruments"
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+            "toc_target_type": "numbered-section",
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+            "title": "<span class=\"os-number\">6.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Observations outside Earth’s Atmosphere</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "6-5-observations-outside-earths-atmosphere"
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+            "title": "<span class=\"os-number\">6.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Future of Large Telescopes</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "6-6-the-future-of-large-telescopes"
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+            "toc_type": "book-content",
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+          {
+            "id": "230ef1dc-e60f-519e-bd57-eb79d71780ea@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
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+          {
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+                "id": "f81a1d22-93c5-57a8-8881-c8f98ed43cd1@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
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+              {
+                "id": "082d1f66-6f3b-516f-b96b-997ee8a49a39@24525b6",
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+                "toc_type": "book-content",
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+                "slug": "6-thought-questions"
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+              {
+                "id": "25eec6f7-dc13-5740-9061-e61b73bf70fa@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
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+      {
+        "id": "0bee6f60-b380-524f-8781-4778b16dd702@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>7</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Other Worlds: An Introduction to the Solar System</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "0bb91d10-14bd-49f7-ae1c-d97d421465b6@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
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+            "title": "<span class=\"os-number\">7.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Overview of Our Planetary System</span>",
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+            "toc_target_type": "numbered-section",
+            "slug": "7-1-overview-of-our-planetary-system"
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+            "title": "<span class=\"os-number\">7.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Dating Planetary Surfaces</span>",
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+            "id": "44040322-e902-5bd1-aa34-0f78bd003da1@24525b6",
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+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "05a1c8d2-7400-4b6a-ada6-c3179952f725@",
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+            "toc_target_type": "intro",
+            "slug": "8-thinking-ahead"
+          },
+          {
+            "id": "7c4fae08-3cc6-4e08-9ee0-12158c0f3071@",
+            "title": "<span class=\"os-number\">8.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Global Perspective</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "8-1-the-global-perspective"
+          },
+          {
+            "id": "06448fca-ae6c-4146-a3e1-b13d8c765c63@",
+            "title": "<span class=\"os-number\">8.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Earth’s Crust</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "8-2-earths-crust"
+          },
+          {
+            "id": "c5fa6993-c0ee-45f0-ab80-c983b0677452@",
+            "title": "<span class=\"os-number\">8.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Earth’s Atmosphere</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "8-3-earths-atmosphere"
+          },
+          {
+            "id": "f9261cd1-436c-498c-aa22-b81749400913@",
+            "title": "<span class=\"os-number\">8.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Life, Chemical Evolution, and Climate Change</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "8-4-life-chemical-evolution-and-climate-change"
+          },
+          {
+            "id": "b90e376a-c576-4e98-88fc-de2b19526a40@",
+            "title": "<span class=\"os-number\">8.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Cosmic Influences on the Evolution of Earth</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "8-5-cosmic-influences-on-the-evolution-of-earth"
+          },
+          {
+            "id": "68c114b9-eb8e-55f2-8a77-c6d7061d7482@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "8-key-terms"
+          },
+          {
+            "id": "7e1a7949-e011-51ca-9d7a-3ddbeeeed1c1@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "8-summary"
+          },
+          {
+            "id": "67713eb9-4cc8-56a5-8e30-64b25f3529e9@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "8-for-further-exploration"
+          },
+          {
+            "id": "135ce91b-37d2-5fcb-b46d-56cd0baea009@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "8-collaborative-group-activities"
+          },
+          {
+            "id": "1f0684c4-1165-5c0c-85ae-947bdf071e81@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "13a07c5b-a9e3-5c02-8411-81427dcfb583@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "8-review-questions"
+              },
+              {
+                "id": "dd9f8118-1801-58a0-8738-b6f9d73ae983@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "8-thought-questions"
+              },
+              {
+                "id": "477a1fcc-2d06-5bfb-b6e1-c7220a5a4d16@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "8-figuring-for-yourself"
+              }
+            ],
+            "slug": "8-exercises"
+          }
+        ],
+        "slug": "8-earth-as-a-planet"
+      },
+      {
+        "id": "39f2b3fe-9ecb-5e52-a91b-c5bb843af093@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>9</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Cratered Worlds</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "f5930002-07c4-4bec-8e25-f3ad35de6963@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "9-thinking-ahead"
+          },
+          {
+            "id": "fa6f6f04-2ea7-4c0a-b792-565198157034@",
+            "title": "<span class=\"os-number\">9.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">General Properties of the Moon</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "9-1-general-properties-of-the-moon"
+          },
+          {
+            "id": "eea4b9d8-6b59-4040-90e8-fead7b28668b@",
+            "title": "<span class=\"os-number\">9.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Lunar Surface</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "9-2-the-lunar-surface"
+          },
+          {
+            "id": "07ca43bf-5858-4ac3-aa7a-d1fd7992fffe@",
+            "title": "<span class=\"os-number\">9.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Impact Craters</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "9-3-impact-craters"
+          },
+          {
+            "id": "f11291b8-079b-49fa-a302-4139c51133f9@",
+            "title": "<span class=\"os-number\">9.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Origin of the Moon</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "9-4-the-origin-of-the-moon"
+          },
+          {
+            "id": "c4fdaa69-9e6a-436c-a27a-d7e2cf95e45c@",
+            "title": "<span class=\"os-number\">9.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Mercury</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "9-5-mercury"
+          },
+          {
+            "id": "43b954f4-f0e3-5b5b-8818-e6c07c464391@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "9-key-terms"
+          },
+          {
+            "id": "4d6aab28-4a1d-53af-9630-834c3d61bbe6@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "9-summary"
+          },
+          {
+            "id": "232b4c9e-030a-59be-b0a3-1124c3989a16@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "9-for-further-exploration"
+          },
+          {
+            "id": "38d0acbe-c050-5c95-b7f6-633128fd7ee3@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "9-collaborative-group-activities"
+          },
+          {
+            "id": "2ceed067-bcb8-53ad-a2a8-70fde1b7660d@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "5fa50daf-30c1-5e02-a08b-b56ff04c0b80@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "9-review-questions"
+              },
+              {
+                "id": "2e6f82ba-56f4-5700-93e5-be3a4f1d3c05@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "9-thought-questions"
+              },
+              {
+                "id": "2bc53836-6b9a-54ce-a207-313e888a18d6@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "9-figuring-for-yourself"
+              }
+            ],
+            "slug": "9-exercises"
+          }
+        ],
+        "slug": "9-cratered-worlds"
+      },
+      {
+        "id": "34b2195c-cdf9-571f-b3f2-625f9d175f9e@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>10</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Earthlike Planets: Venus and Mars</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "bd3a9cb6-eecc-42fb-9626-6bc145004074@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "10-thinking-ahead"
+          },
+          {
+            "id": "c76a2699-5934-4efd-b059-3213342d048c@",
+            "title": "<span class=\"os-number\">10.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nearest Planets: An Overview</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "10-1-the-nearest-planets-an-overview"
+          },
+          {
+            "id": "e10c1a16-d06c-4057-8813-29ae446efe94@",
+            "title": "<span class=\"os-number\">10.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Geology of Venus</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "10-2-the-geology-of-venus"
+          },
+          {
+            "id": "41d0c477-4230-42e8-a1b0-ba1317d9b909@",
+            "title": "<span class=\"os-number\">10.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Massive Atmosphere of Venus</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "10-3-the-massive-atmosphere-of-venus"
+          },
+          {
+            "id": "93c3c498-3673-4622-bdb2-7db24243affa@",
+            "title": "<span class=\"os-number\">10.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Geology of Mars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "10-4-the-geology-of-mars"
+          },
+          {
+            "id": "d163b409-95d7-49e2-a04c-9dcd5e373719@",
+            "title": "<span class=\"os-number\">10.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Water and Life on Mars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "10-5-water-and-life-on-mars"
+          },
+          {
+            "id": "db6df2ee-5f21-4089-b8b8-df88a87480e9@",
+            "title": "<span class=\"os-number\">10.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Divergent Planetary Evolution</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "10-6-divergent-planetary-evolution"
+          },
+          {
+            "id": "9969772a-e0fa-5bde-aac1-f41c43567ccf@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "10-key-terms"
+          },
+          {
+            "id": "e0e9166b-91b2-5446-9567-7e135e6a2573@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "10-summary"
+          },
+          {
+            "id": "8dcbd0a4-8449-58dd-ad02-86f84e085191@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "10-for-further-exploration"
+          },
+          {
+            "id": "e9cb534d-6f30-569d-b318-85e1dfa72151@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "10-collaborative-group-activities"
+          },
+          {
+            "id": "4d84197b-07a2-57e8-b0ce-a3138f076d49@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "79bee2b6-021c-543d-8686-304d26ea7732@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "10-review-questions"
+              },
+              {
+                "id": "92c96bdf-c2fa-5994-83a3-7a02b96ee531@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "10-thought-questions"
+              },
+              {
+                "id": "f130004d-c7bd-544d-9ecd-e93ac8957b43@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "10-figuring-for-yourself"
+              }
+            ],
+            "slug": "10-exercises"
+          }
+        ],
+        "slug": "10-earthlike-planets-venus-and-mars"
+      },
+      {
+        "id": "aa45d25e-fb6e-5120-ae56-cbd62c21d815@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>11</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Giant Planets</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "24137f9b-61e6-48d5-8ea1-e6fe7fc644d3@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "11-thinking-ahead"
+          },
+          {
+            "id": "d9cfd957-5241-4611-abff-426e7b4f7a0c@",
+            "title": "<span class=\"os-number\">11.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Exploring the Outer Planets</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "11-1-exploring-the-outer-planets"
+          },
+          {
+            "id": "139674ba-d381-46a3-b07e-50d0fca52b12@",
+            "title": "<span class=\"os-number\">11.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Giant Planets</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "11-2-the-giant-planets"
+          },
+          {
+            "id": "8215f9ce-0a31-4c2e-a6de-bbd5931d229a@",
+            "title": "<span class=\"os-number\">11.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Atmospheres of the Giant Planets</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "11-3-atmospheres-of-the-giant-planets"
+          },
+          {
+            "id": "5883744c-25a3-5d03-a5f7-1d992312307a@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "11-key-terms"
+          },
+          {
+            "id": "ac350723-8733-56de-a7dd-8a9b6c45926d@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "11-summary"
+          },
+          {
+            "id": "3d16efb7-b2ef-5366-920e-dd4aedc5e40c@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "11-for-further-exploration"
+          },
+          {
+            "id": "176d2cf7-2a5e-5e2b-a888-00276d8b2292@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "11-collaborative-group-activities"
+          },
+          {
+            "id": "c2291d65-07c0-59e6-ac23-7e19b3fd1bc3@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "66f15fd3-ae24-5a6e-86bd-fd11f22e9934@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "11-review-questions"
+              },
+              {
+                "id": "84e4ec2b-6ec5-5e6f-b248-82ab77d0d42b@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "11-thought-questions"
+              },
+              {
+                "id": "eba8a0a9-3b27-5049-a92d-42181436b9c9@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "11-figuring-for-yourself"
+              }
+            ],
+            "slug": "11-exercises"
+          }
+        ],
+        "slug": "11-the-giant-planets"
+      },
+      {
+        "id": "6a13f500-919f-58ed-8650-cda1ae28d36c@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>12</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Rings, Moons, and Pluto</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "760cf33c-7669-4f5f-a68e-e74a63d3731f@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "12-thinking-ahead"
+          },
+          {
+            "id": "a03c22a2-3d5b-4ffc-a773-71bf1c98b7f0@",
+            "title": "<span class=\"os-number\">12.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Ring and Moon Systems Introduced</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "12-1-ring-and-moon-systems-introduced"
+          },
+          {
+            "id": "0bf21b5e-5915-4804-b7a9-ef67fef5c7e8@",
+            "title": "<span class=\"os-number\">12.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Galilean Moons of Jupiter</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "12-2-the-galilean-moons-of-jupiter"
+          },
+          {
+            "id": "bdc41f58-f869-444a-b939-9c73c0a48d15@",
+            "title": "<span class=\"os-number\">12.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Titan and Triton</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "12-3-titan-and-triton"
+          },
+          {
+            "id": "6e41304f-cdf5-4a3a-b5f1-0fd49bd85023@",
+            "title": "<span class=\"os-number\">12.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Pluto and Charon</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "12-4-pluto-and-charon"
+          },
+          {
+            "id": "8b8a7842-b3fd-4fda-aa7a-8fa137a1dc42@",
+            "title": "<span class=\"os-number\">12.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Planetary Rings (and Enceladus)</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "12-5-planetary-rings-and-enceladus"
+          },
+          {
+            "id": "751a867d-468f-5d74-8701-7bac8ded8408@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "12-key-terms"
+          },
+          {
+            "id": "81ae8c53-8cc3-5d14-b713-8f7975e18068@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "12-summary"
+          },
+          {
+            "id": "ded490db-11f2-5e36-9ded-d9d1ac792c7e@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "12-for-further-exploration"
+          },
+          {
+            "id": "262989c3-345c-5065-b1b5-8251d54cb9fc@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "12-collaborative-group-activities"
+          },
+          {
+            "id": "4a150f1e-089f-5d34-9aa9-c3cfc3d63204@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "0be2ec3a-150f-55a9-9e47-55a22fc6bd6a@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "12-review-questions"
+              },
+              {
+                "id": "a1102f2e-5c1a-5252-971d-437f4348e671@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "12-thought-questions"
+              },
+              {
+                "id": "983e393d-310c-545e-8f85-1f1b575db409@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "12-figuring-for-yourself"
+              }
+            ],
+            "slug": "12-exercises"
+          }
+        ],
+        "slug": "12-rings-moons-and-pluto"
+      },
+      {
+        "id": "827a1bea-4053-5a07-bad5-97f7a478419f@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>13</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Comets and Asteroids: Debris of the Solar System</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "46f47a00-a325-4985-a7e2-92ac70b2483a@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "13-thinking-ahead"
+          },
+          {
+            "id": "721b4675-43e5-47fc-95ed-0eb06cc49d36@",
+            "title": "<span class=\"os-number\">13.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Asteroids</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "13-1-asteroids"
+          },
+          {
+            "id": "b1750def-8849-4ae6-87d0-b7a993fc2c24@",
+            "title": "<span class=\"os-number\">13.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Asteroids and Planetary Defense</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "13-2-asteroids-and-planetary-defense"
+          },
+          {
+            "id": "0adc3d85-995c-427e-a4d1-c90b6161f1e4@",
+            "title": "<span class=\"os-number\">13.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The “Long-Haired” Comets</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "13-3-the-long-haired-comets"
+          },
+          {
+            "id": "9aca755b-b169-427f-b460-894e739504b5@",
+            "title": "<span class=\"os-number\">13.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Origin and Fate of Comets and Related Objects</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "13-4-the-origin-and-fate-of-comets-and-related-objects"
+          },
+          {
+            "id": "ee20a483-c518-52c7-84dd-53c5d50955cb@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "13-key-terms"
+          },
+          {
+            "id": "5443c78b-2d01-5c95-b4dc-b0c776a1a3c5@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "13-summary"
+          },
+          {
+            "id": "0300c939-9813-5e39-85b6-8c66604a684f@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "13-for-further-exploration"
+          },
+          {
+            "id": "0a696104-1fce-503f-9d81-044bfe13970c@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "13-collaborative-group-activities"
+          },
+          {
+            "id": "3014d24d-6820-5c7b-9618-c93a16542225@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "84f017eb-f4f2-52ae-bfd0-6e34cef464f6@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "13-review-questions"
+              },
+              {
+                "id": "6968b908-3f74-57cc-a5ec-5b8ada55a38c@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "13-thought-questions"
+              },
+              {
+                "id": "d40e20dc-212e-58d7-9b1c-33ba7d0f89bf@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "13-figuring-for-yourself"
+              }
+            ],
+            "slug": "13-exercises"
+          }
+        ],
+        "slug": "13-comets-and-asteroids-debris-of-the-solar-system"
+      },
+      {
+        "id": "cf144e92-a507-5a2f-b2c8-8ca58cd6244f@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>14</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Cosmic Samples and the Origin of the Solar System</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "821ee95d-a7c5-44fc-9a15-c6aadaaa8b51@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "14-thinking-ahead"
+          },
+          {
+            "id": "399c3a6d-5dba-4317-9e4d-51ac95c86e5a@",
+            "title": "<span class=\"os-number\">14.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Meteors</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "14-1-meteors"
+          },
+          {
+            "id": "b8fcd786-2d2e-415f-8ce8-a61442d8e6b9@",
+            "title": "<span class=\"os-number\">14.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Meteorites: Stones from Heaven</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "14-2-meteorites-stones-from-heaven"
+          },
+          {
+            "id": "d3960789-d139-4c88-870e-982093388aa6@",
+            "title": "<span class=\"os-number\">14.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Formation of the Solar System</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "14-3-formation-of-the-solar-system"
+          },
+          {
+            "id": "32d4a7d0-c061-4fd7-a687-d698a04da5e4@",
+            "title": "<span class=\"os-number\">14.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Comparison with Other Planetary Systems</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "14-4-comparison-with-other-planetary-systems"
+          },
+          {
+            "id": "06733e8f-49db-4a2f-bbe0-0d949d4949a8@",
+            "title": "<span class=\"os-number\">14.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Planetary Evolution</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "14-5-planetary-evolution"
+          },
+          {
+            "id": "f2c38a67-5254-5a4b-b12b-c92bff5622ff@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "14-key-terms"
+          },
+          {
+            "id": "801aa218-797e-5ea8-9f39-e9ca8d63ea0a@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "14-summary"
+          },
+          {
+            "id": "3596165c-86f0-553e-a80c-b10c00418288@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "14-for-further-exploration"
+          },
+          {
+            "id": "97da3361-f782-544d-ac17-dc54abb290d5@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "14-collaborative-group-activities"
+          },
+          {
+            "id": "889ff650-7a6d-53ca-9f2b-a5be358e2459@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "9206a42b-f983-5d6b-bf37-e88cfa424f33@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "14-review-questions"
+              },
+              {
+                "id": "dd3a14c6-5063-559d-ba97-8740a218dc6f@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "14-thought-questions"
+              },
+              {
+                "id": "e6715fba-bde3-585b-ba59-73d60ff49ab1@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "14-figuring-for-yourself"
+              }
+            ],
+            "slug": "14-exercises"
+          }
+        ],
+        "slug": "14-cosmic-samples-and-the-origin-of-the-solar-system"
+      },
+      {
+        "id": "ba9f2785-dc8e-55ce-92b3-f065cfdc9d96@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>15</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Sun: A Garden-Variety Star</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "da30e85d-e625-4c76-bd12-77270b8d4f9b@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "15-thinking-ahead"
+          },
+          {
+            "id": "97449e6c-5612-433b-9586-c078970c1a2e@",
+            "title": "<span class=\"os-number\">15.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Structure and Composition of the Sun</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "15-1-the-structure-and-composition-of-the-sun"
+          },
+          {
+            "id": "f4a8969d-bbef-4f5d-a2ef-fa45a3625aa4@",
+            "title": "<span class=\"os-number\">15.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Solar Cycle</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "15-2-the-solar-cycle"
+          },
+          {
+            "id": "a20c81bb-271c-4862-b4a8-4bda31bb3a2a@",
+            "title": "<span class=\"os-number\">15.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Solar Activity above the Photosphere</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "15-3-solar-activity-above-the-photosphere"
+          },
+          {
+            "id": "2c84c2af-e198-435e-8402-bdb41fab1954@",
+            "title": "<span class=\"os-number\">15.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Space Weather</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "15-4-space-weather"
+          },
+          {
+            "id": "6456a9eb-3668-5088-9816-89fdc720a7fe@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "15-key-terms"
+          },
+          {
+            "id": "b1a77d95-741c-5978-b853-7557efd21766@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "15-summary"
+          },
+          {
+            "id": "166a26ce-c73f-5a12-af84-a8df475832c4@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "15-for-further-exploration"
+          },
+          {
+            "id": "7cfb20d9-d915-5d4e-8a4b-923194389713@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "15-collaborative-group-activities"
+          },
+          {
+            "id": "a8e295bc-4a0a-5eb0-9d23-34c64a97b39e@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "5eca84ce-de5b-5611-990a-8becf80b1690@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "15-review-questions"
+              },
+              {
+                "id": "532db4b5-f4e3-5adb-9058-235f91804b87@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "15-thought-questions"
+              },
+              {
+                "id": "a068ca83-8623-5858-896b-feea89c1663a@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "15-figuring-for-yourself"
+              }
+            ],
+            "slug": "15-exercises"
+          }
+        ],
+        "slug": "15-the-sun-a-garden-variety-star"
+      },
+      {
+        "id": "a0b64668-264d-5856-b581-6cb222a70f35@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>16</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Sun: A Nuclear Powerhouse</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "3e4a13f1-3aeb-4fe2-b9f5-dc354139c29f@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "16-thinking-ahead"
+          },
+          {
+            "id": "0ac646fb-3bf3-498e-a911-c80b917508a4@",
+            "title": "<span class=\"os-number\">16.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Sources of Sunshine: Thermal and Gravitational Energy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "16-1-sources-of-sunshine-thermal-and-gravitational-energy"
+          },
+          {
+            "id": "48c2dc44-40da-465e-b524-0adefbbc1490@",
+            "title": "<span class=\"os-number\">16.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Mass, Energy, and the Theory of Relativity</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "16-2-mass-energy-and-the-theory-of-relativity"
+          },
+          {
+            "id": "808fd050-635a-4043-9f03-612a5a799c78@",
+            "title": "<span class=\"os-number\">16.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Solar Interior: Theory</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "16-3-the-solar-interior-theory"
+          },
+          {
+            "id": "29321b1a-92b6-46a1-8647-2322d31a2426@",
+            "title": "<span class=\"os-number\">16.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Solar Interior: Observations</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "16-4-the-solar-interior-observations"
+          },
+          {
+            "id": "d0c0d984-378a-5626-b12b-32e99365878c@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "16-key-terms"
+          },
+          {
+            "id": "3bacf7ce-950b-5790-bc13-a37a92242dfe@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "16-summary"
+          },
+          {
+            "id": "bf2d3b85-46de-55e6-bc81-97f1d701623d@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "16-for-further-exploration"
+          },
+          {
+            "id": "663a2148-7506-5ebe-8447-c9daa5e72aa5@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "16-collaborative-group-activities"
+          },
+          {
+            "id": "9de9020e-0782-5a4c-96f5-e42f27ea47c8@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "ab693c4c-e517-5a06-86fc-a31c90207a73@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "16-review-questions"
+              },
+              {
+                "id": "4517f013-95d5-5c26-8a1e-112b033ab135@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "16-thought-questions"
+              },
+              {
+                "id": "d8e4e089-a21b-52e1-82fc-920c8a001af0@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "16-figuring-for-yourself"
+              }
+            ],
+            "slug": "16-exercises"
+          }
+        ],
+        "slug": "16-the-sun-a-nuclear-powerhouse"
+      },
+      {
+        "id": "4e1f1bf5-35f2-5fbb-88fd-1ac88d77c732@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>17</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Analyzing Starlight</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "9d28d6da-b855-4cfe-b629-54620023f99c@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "17-thinking-ahead"
+          },
+          {
+            "id": "c2e301e8-00d7-40aa-adc6-5074e1780167@",
+            "title": "<span class=\"os-number\">17.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Brightness of Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "17-1-the-brightness-of-stars"
+          },
+          {
+            "id": "ae03b328-30e7-4be5-a3fb-f1ea6f56407e@",
+            "title": "<span class=\"os-number\">17.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Colors of Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "17-2-colors-of-stars"
+          },
+          {
+            "id": "d1261637-6e72-43d8-be82-54d3e5a3d1e0@",
+            "title": "<span class=\"os-number\">17.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Spectra of Stars (and Brown Dwarfs)</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "17-3-the-spectra-of-stars-and-brown-dwarfs"
+          },
+          {
+            "id": "167aaaa5-7530-49bd-b110-21d10d7cd56b@",
+            "title": "<span class=\"os-number\">17.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Using Spectra to Measure Stellar Radius, Composition, and Motion</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "17-4-using-spectra-to-measure-stellar-radius-composition-and-motion"
+          },
+          {
+            "id": "88205381-f8d1-54b0-8a72-b8b3ae25a1e3@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "17-key-terms"
+          },
+          {
+            "id": "097df605-c1ea-55fe-b3ce-8f7e2830b75f@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "17-summary"
+          },
+          {
+            "id": "d29cc47f-de03-5a77-824e-98bbc9014e01@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "17-for-further-exploration"
+          },
+          {
+            "id": "0e05a553-20a1-5b14-aa22-55227e3e6749@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "17-collaborative-group-activities"
+          },
+          {
+            "id": "95354a5c-41eb-5710-8c10-62f030cf5f36@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "40f2b0f0-e7fe-5326-8f4c-acd8ce8ef3d2@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "17-review-questions"
+              },
+              {
+                "id": "14740931-bc9d-5ace-a0de-a97922f5274c@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "17-thought-questions"
+              },
+              {
+                "id": "527fedf7-a2f4-5b02-ac43-2f1ce798b4f1@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "17-figuring-for-yourself"
+              }
+            ],
+            "slug": "17-exercises"
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+        ],
+        "slug": "17-analyzing-starlight"
+      },
+      {
+        "id": "feb2f4f4-5fce-590f-8a4c-8f879d306b22@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>18</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Stars: A Celestial Census</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "810ba736-3e15-48e2-9491-cf0f401611c3@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "18-thinking-ahead"
+          },
+          {
+            "id": "f6dd7bbd-c01f-4c46-b50c-851f6fdedd2e@",
+            "title": "<span class=\"os-number\">18.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Stellar Census</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "18-1-a-stellar-census"
+          },
+          {
+            "id": "7eb90491-5946-4150-9c21-38c946124a55@",
+            "title": "<span class=\"os-number\">18.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Measuring Stellar Masses</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "18-2-measuring-stellar-masses"
+          },
+          {
+            "id": "7b355f77-984b-4af1-b188-97ddeb9e658b@",
+            "title": "<span class=\"os-number\">18.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Diameters of Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "18-3-diameters-of-stars"
+          },
+          {
+            "id": "11581e86-b3c6-45ea-bd3e-0d55a8f12ab8@",
+            "title": "<span class=\"os-number\">18.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The H–R Diagram</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "18-4-the-h-r-diagram"
+          },
+          {
+            "id": "ca417f24-20d5-5db8-aa06-47ecb5b5337f@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "18-key-terms"
+          },
+          {
+            "id": "257f91ab-4f86-5678-b6fd-626c33a8c625@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "18-summary"
+          },
+          {
+            "id": "5b616c97-75ae-576d-b7f6-fc51ffc3d803@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "18-for-further-exploration"
+          },
+          {
+            "id": "24f74dcc-098e-50e6-8cf1-3cfacb5081f0@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "18-collaborative-group-activities"
+          },
+          {
+            "id": "d0c42095-ca7a-55fe-a507-921c278f256b@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "a615a27f-d0ff-5328-a49d-0c06d6140d2f@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "18-review-questions"
+              },
+              {
+                "id": "896598be-427e-5031-ac8a-9f411e70580c@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "18-thought-questions"
+              },
+              {
+                "id": "76bc7bc4-a224-5422-a638-c13643d92348@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "18-figuring-for-yourself"
+              }
+            ],
+            "slug": "18-exercises"
+          }
+        ],
+        "slug": "18-the-stars-a-celestial-census"
+      },
+      {
+        "id": "497cd12d-b0c3-51bf-a184-9e05e14d9c8e@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>19</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Celestial Distances</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "1ee1ae44-9a8c-439f-b39d-c385ef80ca3f@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "19-thinking-ahead"
+          },
+          {
+            "id": "495b1319-ab2a-46be-a216-f98692a0eb14@",
+            "title": "<span class=\"os-number\">19.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Fundamental Units of Distance</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "19-1-fundamental-units-of-distance"
+          },
+          {
+            "id": "e7866b9e-59bd-4e63-a285-58320ddaf41c@",
+            "title": "<span class=\"os-number\">19.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Surveying the Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "19-2-surveying-the-stars"
+          },
+          {
+            "id": "bdd59622-7b70-46bd-948f-3651c94d230b@",
+            "title": "<span class=\"os-number\">19.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Variable Stars: One Key to Cosmic Distances</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "19-3-variable-stars-one-key-to-cosmic-distances"
+          },
+          {
+            "id": "6956e36d-e32e-4e3d-83d8-ca2a23a411d4@",
+            "title": "<span class=\"os-number\">19.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The H–R Diagram and Cosmic Distances</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "19-4-the-h-r-diagram-and-cosmic-distances"
+          },
+          {
+            "id": "ce0a3b20-d659-544f-be83-6e77a65e69c2@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "19-key-terms"
+          },
+          {
+            "id": "03e3eaa0-feab-55e7-a77b-4e71fac2eb65@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "19-summary"
+          },
+          {
+            "id": "27e9dec1-54f7-5d23-b959-724e2c8a06b8@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "19-for-further-exploration"
+          },
+          {
+            "id": "b5dc5b9a-8380-58a6-a318-bec37596fde1@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "19-collaborative-group-activities"
+          },
+          {
+            "id": "4d618b53-b25e-56f6-a63c-88f282c77ed2@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "741eecab-1f0c-58d5-bf3f-7fd8a40c046d@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "19-review-questions"
+              },
+              {
+                "id": "cc3e5d3a-4286-57df-b77c-ff6be961b807@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "19-thought-questions"
+              },
+              {
+                "id": "ef7880d8-9a61-5bcf-911f-8736919891d0@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "19-figuring-for-yourself"
+              }
+            ],
+            "slug": "19-exercises"
+          }
+        ],
+        "slug": "19-celestial-distances"
+      },
+      {
+        "id": "9da9b4a6-4def-5b76-9dac-039e0a8d7a69@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>20</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Between the Stars: Gas and Dust in Space</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "73158c18-de2f-4a95-b9cf-3ac65c11cbe0@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "20-thinking-ahead"
+          },
+          {
+            "id": "0e4c42c9-c91a-4c41-9ad1-116621dae208@",
+            "title": "<span class=\"os-number\">20.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Interstellar Medium</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "20-1-the-interstellar-medium"
+          },
+          {
+            "id": "d202bcaf-7f29-43c8-953d-e716c4785ad2@",
+            "title": "<span class=\"os-number\">20.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Interstellar Gas</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "20-2-interstellar-gas"
+          },
+          {
+            "id": "9e1d113d-c083-451f-806a-31b3c54b4a05@",
+            "title": "<span class=\"os-number\">20.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Cosmic Dust</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "20-3-cosmic-dust"
+          },
+          {
+            "id": "a90879d1-ee17-4595-9d79-8e75038891bf@",
+            "title": "<span class=\"os-number\">20.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Cosmic Rays</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "20-4-cosmic-rays"
+          },
+          {
+            "id": "ed257b38-6523-4a4d-a227-24223f6753bc@",
+            "title": "<span class=\"os-number\">20.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Life Cycle of Cosmic Material</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "20-5-the-life-cycle-of-cosmic-material"
+          },
+          {
+            "id": "e5591420-f150-4160-8b4a-42087b79794b@",
+            "title": "<span class=\"os-number\">20.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Interstellar Matter around the Sun</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "20-6-interstellar-matter-around-the-sun"
+          },
+          {
+            "id": "994d9837-0441-5cf4-8ddd-b484fc2d892b@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "20-key-terms"
+          },
+          {
+            "id": "d66a9927-e3d2-5d11-9574-fce93f368e9c@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "20-summary"
+          },
+          {
+            "id": "80647693-4dd6-591c-8b51-8da29be074eb@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "20-for-further-exploration"
+          },
+          {
+            "id": "7fc9ccc9-acbf-504e-9698-5784653738c8@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "20-collaborative-group-activities"
+          },
+          {
+            "id": "5d864583-87cb-5748-8986-d7c6f7fd2e31@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "670064b4-33bd-5f03-b4cf-852a1779dced@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "20-review-questions"
+              },
+              {
+                "id": "e3280c98-5fcd-59c5-b34e-d02a87fdd7aa@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "20-thought-questions"
+              },
+              {
+                "id": "90b7c114-d88a-59eb-ac33-d2d826606282@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "20-figuring-for-yourself"
+              }
+            ],
+            "slug": "20-exercises"
+          }
+        ],
+        "slug": "20-between-the-stars-gas-and-dust-in-space"
+      },
+      {
+        "id": "f2c3ffff-256c-5d33-88d3-9b5759d134b0@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>21</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Birth of Stars and the Discovery of Planets outside the Solar System</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "a4d25617-b0da-4fe3-8542-322122f7e7d3@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "21-thinking-ahead"
+          },
+          {
+            "id": "d0564568-2e7f-4a39-9252-57b7f53c75d4@",
+            "title": "<span class=\"os-number\">21.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Star Formation</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "21-1-star-formation"
+          },
+          {
+            "id": "c80b855e-bbb9-49a4-89ca-cceaa1621efd@",
+            "title": "<span class=\"os-number\">21.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The H–R Diagram and the Study of Stellar Evolution</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "21-2-the-h-r-diagram-and-the-study-of-stellar-evolution"
+          },
+          {
+            "id": "e24426f1-be17-4920-9461-8d7d449257df@",
+            "title": "<span class=\"os-number\">21.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evidence That Planets Form around Other Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "21-3-evidence-that-planets-form-around-other-stars"
+          },
+          {
+            "id": "c86ab422-c09c-4b54-810c-f1432eb3c342@",
+            "title": "<span class=\"os-number\">21.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Planets beyond the Solar System: Search and Discovery</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "21-4-planets-beyond-the-solar-system-search-and-discovery"
+          },
+          {
+            "id": "fa826ec8-d865-4fc5-bbc6-b7643788d709@",
+            "title": "<span class=\"os-number\">21.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Exoplanets Everywhere: What We Are Learning</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "21-5-exoplanets-everywhere-what-we-are-learning"
+          },
+          {
+            "id": "b6b6db26-7ae7-4735-a8da-988c26104485@",
+            "title": "<span class=\"os-number\">21.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">New Perspectives on Planet Formation</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "21-6-new-perspectives-on-planet-formation"
+          },
+          {
+            "id": "f4a4ae6f-5597-52f8-9e71-549ecebbcad2@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "21-key-terms"
+          },
+          {
+            "id": "cbf08b5e-4094-5a43-a70d-02b59a732a31@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "21-summary"
+          },
+          {
+            "id": "4ab44299-c350-5db4-8382-1ff41e49ed01@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "21-for-further-exploration"
+          },
+          {
+            "id": "27464d3b-a232-545a-928d-8d157e05ff1d@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "21-collaborative-group-activities"
+          },
+          {
+            "id": "4852f557-cab2-50ad-903d-4f44dbfb3cc6@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "fa50cfee-b017-543e-8ff9-0ef57dbb3764@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "21-review-questions"
+              },
+              {
+                "id": "76a8cf10-692d-58bc-8348-6ee0498b828f@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "21-thought-questions"
+              },
+              {
+                "id": "33bfb46d-a5e6-5b7c-a660-de2e59f34678@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "21-figuring-for-yourself"
+              }
+            ],
+            "slug": "21-exercises"
+          }
+        ],
+        "slug": "21-the-birth-of-stars-and-the-discovery-of-planets-outside-the-solar-system"
+      },
+      {
+        "id": "19044b53-b381-5840-b2e7-3517e304a71a@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>22</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Stars from Adolescence to Old Age</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "46b88c58-3f68-469e-98f0-ed46bc80f5a1@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "22-thinking-ahead"
+          },
+          {
+            "id": "8a6e3d45-44dc-48f6-8973-d6f95fbcc318@",
+            "title": "<span class=\"os-number\">22.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evolution from the Main Sequence to Red Giants</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "22-1-evolution-from-the-main-sequence-to-red-giants"
+          },
+          {
+            "id": "22c8446c-af88-4319-9a18-fe03a51bd297@",
+            "title": "<span class=\"os-number\">22.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Star Clusters</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "22-2-star-clusters"
+          },
+          {
+            "id": "94219738-96dc-47ef-b1e0-03c9044e8ac6@",
+            "title": "<span class=\"os-number\">22.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Checking Out the Theory</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "22-3-checking-out-the-theory"
+          },
+          {
+            "id": "780466d0-053e-4f7f-adbd-b0d0dac5c99b@",
+            "title": "<span class=\"os-number\">22.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Further Evolution of Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "22-4-further-evolution-of-stars"
+          },
+          {
+            "id": "a75aea70-4fb6-4d2e-9c29-7d29b55b93ce@",
+            "title": "<span class=\"os-number\">22.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Evolution of More Massive Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "22-5-the-evolution-of-more-massive-stars"
+          },
+          {
+            "id": "4dc35307-7f92-5f80-bafe-5c425415d940@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "22-key-terms"
+          },
+          {
+            "id": "9ea0ec75-0219-58db-ae3e-3841a81fb5ed@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "22-summary"
+          },
+          {
+            "id": "2ce536e8-c640-503f-9bd1-f4bb05aac25d@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "22-for-further-exploration"
+          },
+          {
+            "id": "0a281ade-2a97-51cb-9fda-6b9c8eaa947f@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "22-collaborative-group-activities"
+          },
+          {
+            "id": "657daccd-9cd7-5f59-b757-02b1f7c31060@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "eb31344f-3d4a-54ad-a7e4-5d5442dc3f33@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "22-review-questions"
+              },
+              {
+                "id": "a1c78acc-8234-5de8-833d-aac0010fccdf@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "22-thought-questions"
+              },
+              {
+                "id": "e71a3ca1-8a9a-568d-8a14-e942836c823d@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "22-figuring-for-yourself"
+              }
+            ],
+            "slug": "22-exercises"
+          }
+        ],
+        "slug": "22-stars-from-adolescence-to-old-age"
+      },
+      {
+        "id": "009b1392-bfa6-5821-9bbe-eff449bc4c9a@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>23</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Death of Stars</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "8e460daa-be2b-47de-9d38-ab4c21865a8a@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "23-thinking-ahead"
+          },
+          {
+            "id": "915e3fbb-30e8-464d-ad0f-5a756d205ea7@",
+            "title": "<span class=\"os-number\">23.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Death of Low-Mass Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "23-1-the-death-of-low-mass-stars"
+          },
+          {
+            "id": "ecaa1a98-d696-4822-b88c-1b8e29502ef6@",
+            "title": "<span class=\"os-number\">23.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evolution of Massive Stars: An Explosive Finish</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "23-2-evolution-of-massive-stars-an-explosive-finish"
+          },
+          {
+            "id": "a567ba98-3507-49d5-893c-c05cd42eefa5@",
+            "title": "<span class=\"os-number\">23.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Supernova Observations</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "23-3-supernova-observations"
+          },
+          {
+            "id": "bfeda56d-0942-4640-9f37-619d208eb106@",
+            "title": "<span class=\"os-number\">23.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Pulsars and the Discovery of Neutron Stars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "23-4-pulsars-and-the-discovery-of-neutron-stars"
+          },
+          {
+            "id": "3a787454-c556-4633-895a-ff762fbd2b72@",
+            "title": "<span class=\"os-number\">23.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Evolution of Binary Star Systems</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "23-5-the-evolution-of-binary-star-systems"
+          },
+          {
+            "id": "979ea345-05c5-4720-ae29-212ffb3b6ecd@",
+            "title": "<span class=\"os-number\">23.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Mystery of the Gamma-Ray Bursts</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "23-6-the-mystery-of-the-gamma-ray-bursts"
+          },
+          {
+            "id": "a6a9561d-a717-5fe0-94e3-61251587ddbf@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "23-key-terms"
+          },
+          {
+            "id": "cd03cf4b-2990-5ec5-aa2b-29e12e54bc7f@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "23-summary"
+          },
+          {
+            "id": "11f0d91c-53c9-5d31-8614-ea549bf4b2a2@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "23-for-further-exploration"
+          },
+          {
+            "id": "f97929a8-b88f-5d5e-a316-d19e29a8ddf1@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "23-collaborative-group-activities"
+          },
+          {
+            "id": "ffabc844-acf3-5752-a818-86a39ea25073@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "4dd8af71-40b9-57a7-ad3c-8f6800931748@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "23-review-questions"
+              },
+              {
+                "id": "6c083955-14b0-53fb-a43b-e46bebe6e519@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "23-thought-questions"
+              },
+              {
+                "id": "653362da-ed7c-5c27-98e9-d5001cf1b63c@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "23-figuring-for-yourself"
+              }
+            ],
+            "slug": "23-exercises"
+          }
+        ],
+        "slug": "23-the-death-of-stars"
+      },
+      {
+        "id": "1ab4309b-5308-5eae-a566-e3cea6a84260@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>24</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Black Holes and Curved Spacetime</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "c58084cd-93fa-48ba-82a5-8bc44de393ed@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "24-thinking-ahead"
+          },
+          {
+            "id": "87febba0-f4df-4096-b9f6-a13ed65deb0f@",
+            "title": "<span class=\"os-number\">24.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Introducing General Relativity</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-1-introducing-general-relativity"
+          },
+          {
+            "id": "3ce9d47d-1953-4522-ad16-0a8c17b4cf92@",
+            "title": "<span class=\"os-number\">24.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Spacetime and Gravity</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-2-spacetime-and-gravity"
+          },
+          {
+            "id": "340339c0-3b54-44c0-929a-7fe8b575a8a2@",
+            "title": "<span class=\"os-number\">24.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Tests of General Relativity</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-3-tests-of-general-relativity"
+          },
+          {
+            "id": "e42a160d-33cd-413f-ba2e-d23601880762@",
+            "title": "<span class=\"os-number\">24.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Time in General Relativity</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-4-time-in-general-relativity"
+          },
+          {
+            "id": "366e559d-50aa-4678-b615-bc6f4f06e5cc@",
+            "title": "<span class=\"os-number\">24.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Black Holes</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-5-black-holes"
+          },
+          {
+            "id": "0eb920e0-9e34-4761-b92a-369b0a40ae70@",
+            "title": "<span class=\"os-number\">24.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evidence for Black Holes</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-6-evidence-for-black-holes"
+          },
+          {
+            "id": "b59bbcd2-3e7d-4bf0-8f2d-e2ef9265be3a@",
+            "title": "<span class=\"os-number\">24.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Gravitational Wave Astronomy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "24-7-gravitational-wave-astronomy"
+          },
+          {
+            "id": "29b10d46-33e0-508e-afef-4d74683fa5ef@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "24-key-terms"
+          },
+          {
+            "id": "3caa9650-7edc-57cf-88b5-23343b499b7c@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "24-summary"
+          },
+          {
+            "id": "f1bc374d-f58f-5a95-9144-f81fae834cc8@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "24-for-further-exploration"
+          },
+          {
+            "id": "dbda5721-647d-557f-ad1b-e159f3b05489@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "24-collaborative-group-activities"
+          },
+          {
+            "id": "9eb85f79-2727-539a-bef1-7bc297a5ad72@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "2655c71b-b0b8-5fa9-8152-01786bba960e@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "24-review-questions"
+              },
+              {
+                "id": "1c43497c-8604-5d9a-ade9-240ee3178888@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "24-thought-questions"
+              },
+              {
+                "id": "9d00c01b-5b3f-527f-876b-57501d36a54f@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "24-figuring-for-yourself"
+              }
+            ],
+            "slug": "24-exercises"
+          }
+        ],
+        "slug": "24-black-holes-and-curved-spacetime"
+      },
+      {
+        "id": "d4f64924-3241-59a1-8b91-767141ad52ac@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>25</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Milky Way Galaxy</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "cfa5edb3-71c8-4593-bcef-efbc4dc2d162@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "25-thinking-ahead"
+          },
+          {
+            "id": "80c08cb8-b0ca-49a2-bbb9-87ed85d23745@",
+            "title": "<span class=\"os-number\">25.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Architecture of the Galaxy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "25-1-the-architecture-of-the-galaxy"
+          },
+          {
+            "id": "e5ae30bd-bea0-482e-aa8d-9031fe0a6de5@",
+            "title": "<span class=\"os-number\">25.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Spiral Structure</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "25-2-spiral-structure"
+          },
+          {
+            "id": "3637e692-0455-46d1-a76d-d5a8a0d48e5c@",
+            "title": "<span class=\"os-number\">25.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Mass of the Galaxy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "25-3-the-mass-of-the-galaxy"
+          },
+          {
+            "id": "5bea3219-4ed3-4eba-99a7-8ccd6a723fba@",
+            "title": "<span class=\"os-number\">25.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Center of the Galaxy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "25-4-the-center-of-the-galaxy"
+          },
+          {
+            "id": "42d678ee-f4eb-4208-be35-17206525601f@",
+            "title": "<span class=\"os-number\">25.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Stellar Populations in the Galaxy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "25-5-stellar-populations-in-the-galaxy"
+          },
+          {
+            "id": "f84ec82d-1a65-48ac-af23-44256b829a73@",
+            "title": "<span class=\"os-number\">25.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Formation of the Galaxy</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "25-6-the-formation-of-the-galaxy"
+          },
+          {
+            "id": "ef40ac9d-e8d0-57fb-8ba0-0cf704b6ec26@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "25-key-terms"
+          },
+          {
+            "id": "63582b1e-74fc-5aac-bb7e-d7cccba6971e@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "25-summary"
+          },
+          {
+            "id": "5e72fbbd-a368-56bd-a025-b7b7801ec348@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "25-for-further-exploration"
+          },
+          {
+            "id": "87c70239-2b35-5085-beb9-ad470f17cc37@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "25-collaborative-group-activities"
+          },
+          {
+            "id": "363929df-2999-57bb-a394-a1c8e6c0acf1@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "5691e613-db9d-529c-b092-0943d7eca099@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "25-review-questions"
+              },
+              {
+                "id": "a3754aed-6890-5b14-82b7-a2cc9686fe8c@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "25-thought-questions"
+              },
+              {
+                "id": "cc425769-e9a5-50fe-9de2-17f2bfe44436@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "25-figuring-for-yourself"
+              }
+            ],
+            "slug": "25-exercises"
+          }
+        ],
+        "slug": "25-the-milky-way-galaxy"
+      },
+      {
+        "id": "aa5a3b3a-d69d-5dc7-a6c3-f7f6a64c8a7f@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>26</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Galaxies</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "1db87beb-ec02-4a18-8f7b-fe500224ba2d@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "26-thinking-ahead"
+          },
+          {
+            "id": "7207bf03-f431-490f-af15-d053f957dddd@",
+            "title": "<span class=\"os-number\">26.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Discovery of Galaxies</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "26-1-the-discovery-of-galaxies"
+          },
+          {
+            "id": "2301b05b-62ca-4212-9e3d-b68715f001bf@",
+            "title": "<span class=\"os-number\">26.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Types of Galaxies</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "26-2-types-of-galaxies"
+          },
+          {
+            "id": "d46dc34b-84fa-4abc-8716-e237f6a71142@",
+            "title": "<span class=\"os-number\">26.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Properties of Galaxies</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "26-3-properties-of-galaxies"
+          },
+          {
+            "id": "0fd5bc48-a4a5-4876-83a3-68ea812a662a@",
+            "title": "<span class=\"os-number\">26.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Extragalactic Distance Scale</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "26-4-the-extragalactic-distance-scale"
+          },
+          {
+            "id": "eea58296-1089-4e4d-8805-b0dc4fddea2e@",
+            "title": "<span class=\"os-number\">26.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Expanding Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "26-5-the-expanding-universe"
+          },
+          {
+            "id": "4cfa89d9-5804-594d-b2e6-1dc4493e6ed7@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "26-key-terms"
+          },
+          {
+            "id": "421c45d7-8c22-5df6-a8e5-c391ab8ca185@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "26-summary"
+          },
+          {
+            "id": "0d3f6db3-9095-5935-abf7-96bb6e9fd5b6@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "26-for-further-exploration"
+          },
+          {
+            "id": "e3d66161-3404-52e6-b1ec-960e49811056@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "26-collaborative-group-activities"
+          },
+          {
+            "id": "4c739aa3-a3af-55ff-b09f-c36d83bde70a@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "e46812a6-2df1-5f13-a38f-630ec6b20557@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "26-review-questions"
+              },
+              {
+                "id": "b0d7257b-5143-5fb5-9ed0-9bcd58fa8fa2@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "26-thought-questions"
+              },
+              {
+                "id": "2950b113-2153-5eb6-84d8-829e3df746be@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "26-figuring-for-yourself"
+              }
+            ],
+            "slug": "26-exercises"
+          }
+        ],
+        "slug": "26-galaxies"
+      },
+      {
+        "id": "fdf8cf8a-1b11-54d2-9e7a-09c42db035b9@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>27</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Active Galaxies, Quasars, and Supermassive Black Holes</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "c1576760-aaaf-4663-ac75-4b81891a0cf3@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "27-thinking-ahead"
+          },
+          {
+            "id": "976cd1d5-fa37-4496-b3fa-c1bc770bdadd@",
+            "title": "<span class=\"os-number\">27.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Quasars</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "27-1-quasars"
+          },
+          {
+            "id": "79e546fb-e10c-4604-9cd4-6d64d9535f8c@",
+            "title": "<span class=\"os-number\">27.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Supermassive Black Holes: What Quasars Really Are</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "27-2-supermassive-black-holes-what-quasars-really-are"
+          },
+          {
+            "id": "6abf3134-2c1b-4e20-a4cd-f91360777a8b@",
+            "title": "<span class=\"os-number\">27.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Quasars as Probes of Evolution in the Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "27-3-quasars-as-probes-of-evolution-in-the-universe"
+          },
+          {
+            "id": "db953b77-bb82-5d0d-bbc5-f6766d2835ec@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "27-key-terms"
+          },
+          {
+            "id": "50e8e223-ad29-58bf-97d2-7a92e4582e2e@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "27-summary"
+          },
+          {
+            "id": "93026b74-2ccd-53ee-ad9b-5e137c203a7d@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "27-for-further-exploration"
+          },
+          {
+            "id": "7b052f40-5897-52f2-bb46-614a0b76c4d1@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "27-collaborative-group-activities"
+          },
+          {
+            "id": "d14f133c-8715-5945-8ab7-90101b92bd65@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "90dabfb1-5dbf-5a2c-ab12-b7fd81eda98d@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "27-review-questions"
+              },
+              {
+                "id": "5f141414-ae50-5925-a59f-af539d6a7bc2@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "27-thought-questions"
+              },
+              {
+                "id": "84f2d243-0179-58bc-a9b9-a5c7bf2ce011@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "27-figuring-for-yourself"
+              }
+            ],
+            "slug": "27-exercises"
+          }
+        ],
+        "slug": "27-active-galaxies-quasars-and-supermassive-black-holes"
+      },
+      {
+        "id": "1b8159d9-44c1-5cef-820a-94aa75f933cd@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>28</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Evolution and Distribution of Galaxies</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "d7f7bff9-fe26-4af6-bb4c-b2869541c71a@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "28-thinking-ahead"
+          },
+          {
+            "id": "1e224c17-74f4-4082-988d-13dc5475aeda@",
+            "title": "<span class=\"os-number\">28.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Observations of Distant Galaxies</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "28-1-observations-of-distant-galaxies"
+          },
+          {
+            "id": "06b43416-8559-4c50-b870-e9fda268bf4e@",
+            "title": "<span class=\"os-number\">28.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Galaxy Mergers and Active Galactic Nuclei</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "28-2-galaxy-mergers-and-active-galactic-nuclei"
+          },
+          {
+            "id": "09cab279-1255-4465-b14a-ca893103f2e8@",
+            "title": "<span class=\"os-number\">28.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Distribution of Galaxies in Space</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "28-3-the-distribution-of-galaxies-in-space"
+          },
+          {
+            "id": "b063470e-4c67-4956-ac8b-aa08510a414f@",
+            "title": "<span class=\"os-number\">28.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Challenge of Dark Matter</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
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+            "id": "0553dc16-7f85-4d2b-b6d4-aea5dc9dc4ed@",
+            "title": "<span class=\"os-number\">28.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Formation and Evolution of Galaxies and Structure in the Universe</span>",
+            "toc_type": "book-content",
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+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "28-summary"
+          },
+          {
+            "id": "0f885ff5-0a57-5f25-9f82-779309f64ffc@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
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+          },
+          {
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+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "28-collaborative-group-activities"
+          },
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+            "id": "5fb08c71-c8db-55d7-bd0b-95827f6257e9@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "55f9a2f8-0ea7-555b-a185-9f75b05b73f7@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "28-review-questions"
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+              {
+                "id": "8753e1cd-ddc6-5d32-a86e-39a18e656595@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "28-thought-questions"
+              },
+              {
+                "id": "6062cbac-ddcf-53da-af22-ad651e4a7522@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "28-figuring-for-yourself"
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+        ],
+        "slug": "28-the-evolution-and-distribution-of-galaxies"
+      },
+      {
+        "id": "ce79f7c3-429d-5bb7-9661-181282131a9c@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>29</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Big Bang</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "c4987953-c1a0-4df4-8d01-1d0df7ae228f@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "29-thinking-ahead"
+          },
+          {
+            "id": "81ac6512-f327-4a65-b2f7-ffa9e2b14302@",
+            "title": "<span class=\"os-number\">29.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Age of the Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-1-the-age-of-the-universe"
+          },
+          {
+            "id": "df0a1d5f-b241-42e4-843f-57fbd3c5c1f1@",
+            "title": "<span class=\"os-number\">29.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Model of the Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-2-a-model-of-the-universe"
+          },
+          {
+            "id": "aa165ae9-6681-4297-94e1-c013f7cf15fc@",
+            "title": "<span class=\"os-number\">29.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Beginning of the Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-3-the-beginning-of-the-universe"
+          },
+          {
+            "id": "2d06b339-8230-4298-a7e7-72771b1a40a9@",
+            "title": "<span class=\"os-number\">29.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Cosmic Microwave Background</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-4-the-cosmic-microwave-background"
+          },
+          {
+            "id": "6a24271c-6c9f-4178-92a5-b5e2234f13cf@",
+            "title": "<span class=\"os-number\">29.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">What Is the Universe Really Made Of?</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-5-what-is-the-universe-really-made-of"
+          },
+          {
+            "id": "0ff79f0f-13c3-4e5b-8f86-24a52fc009b4@",
+            "title": "<span class=\"os-number\">29.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Inflationary Universe</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-6-the-inflationary-universe"
+          },
+          {
+            "id": "0cb5d17a-1dff-44d4-af38-803d675f303c@",
+            "title": "<span class=\"os-number\">29.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Anthropic Principle</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "29-7-the-anthropic-principle"
+          },
+          {
+            "id": "1c536721-7310-56cb-b6bf-a324dc3a56b8@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "29-key-terms"
+          },
+          {
+            "id": "25ce4e91-85a4-5442-bfaa-91c3f8a3e1e0@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "29-summary"
+          },
+          {
+            "id": "b29c0a00-b577-5fbf-9add-5b51b076ab6a@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "29-for-further-exploration"
+          },
+          {
+            "id": "afb23ddb-dcd6-55ce-8c70-2ae2714ee3f0@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "29-collaborative-group-activities"
+          },
+          {
+            "id": "7ffbee66-b6dd-59a9-911b-f03f65df739e@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "cc267582-f1e5-51dd-b5ed-d9ed8c86f731@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "29-review-questions"
+              },
+              {
+                "id": "77c7de85-0fd0-5878-81d8-3c1de81be57e@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "29-thought-questions"
+              },
+              {
+                "id": "e927dd39-8779-5afa-b40c-65ed3e854667@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "29-figuring-for-yourself"
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+            "slug": "29-exercises"
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+        ],
+        "slug": "29-the-big-bang"
+      },
+      {
+        "id": "6d7c0907-8bd7-531c-b99d-b9e2d10a5b3f@24525b6",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>30</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Life in the Universe</span>",
+        "toc_type": "chapter",
+        "contents": [
+          {
+            "id": "7ac95c9e-6713-43a4-adf8-c8285882caaa@",
+            "title": "<span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "intro",
+            "slug": "30-thinking-ahead"
+          },
+          {
+            "id": "f302e4d4-b5fd-41bc-8d19-99dcb7e819a2@",
+            "title": "<span class=\"os-number\">30</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Cosmic Context for Life</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "30-1-the-cosmic-context-for-life"
+          },
+          {
+            "id": "6e5659bc-b570-4cc3-8078-1eb4acd3b8fc@",
+            "title": "<span class=\"os-number\">30.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Astrobiology</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "30-2-astrobiology"
+          },
+          {
+            "id": "be446a6a-8a98-4999-9ee3-e830ec801ed2@",
+            "title": "<span class=\"os-number\">30.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Searching for Life beyond Earth</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "30-3-searching-for-life-beyond-earth"
+          },
+          {
+            "id": "71ee00eb-d39d-437c-9a85-9a8db4309fe3@",
+            "title": "<span class=\"os-number\">30.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Search for Extraterrestrial Intelligence</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "numbered-section",
+            "slug": "30-4-the-search-for-extraterrestrial-intelligence"
+          },
+          {
+            "id": "76853ba6-8909-563f-a331-922d6088b270@24525b6",
+            "title": "<span class=\"os-text\">Key Terms</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "30-key-terms"
+          },
+          {
+            "id": "084049c3-342c-57d8-8aa1-fa7a9a4f6665@24525b6",
+            "title": "<span class=\"os-text\">Summary</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "30-summary"
+          },
+          {
+            "id": "0eaf4ab1-6832-5d1c-a8e9-169487b2a337@24525b6",
+            "title": "<span class=\"os-text\">For Further Exploration</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "30-for-further-exploration"
+          },
+          {
+            "id": "e67b2ba5-dbf5-5266-895c-1bd350187e36@24525b6",
+            "title": "<span class=\"os-text\">Collaborative Group Activities</span>",
+            "toc_type": "book-content",
+            "toc_target_type": "composite-page",
+            "slug": "30-collaborative-group-activities"
+          },
+          {
+            "id": "17f99b7f-6d0c-5884-8aa7-d27f40d03702@24525b6",
+            "title": "<span class=\"os-text\">Exercises</span>",
+            "toc_type": "sub-book-tree",
+            "contents": [
+              {
+                "id": "2a80add4-220b-5813-8f61-b11d1d5bbf7b@24525b6",
+                "title": "<span class=\"os-text\">Review Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "30-review-questions"
+              },
+              {
+                "id": "9a05fb9c-85f5-5f4a-905f-b6f810d2b77c@24525b6",
+                "title": "<span class=\"os-text\">Thought Questions</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "30-thought-questions"
+              },
+              {
+                "id": "1b04756d-f897-525d-9c35-fb93e7fcff43@24525b6",
+                "title": "<span class=\"os-text\">Figuring for Yourself</span>",
+                "toc_type": "book-content",
+                "toc_target_type": "composite-page",
+                "slug": "30-figuring-for-yourself"
+              }
+            ],
+            "slug": "30-exercises"
+          }
+        ],
+        "slug": "30-life-in-the-universe"
+      },
+      {
+        "id": "4a274b24-cc3d-4264-b5c5-7527026d831e@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>A</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">How to Study for an Introductory Astronomy Class</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "a-how-to-study-for-an-introductory-astronomy-class"
+      },
+      {
+        "id": "5828cbfc-03c0-436c-8efe-264a5de96b94@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>B</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Astronomy Websites, Images, and Apps</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "b-astronomy-websites-images-and-apps"
+      },
+      {
+        "id": "b51ff343-f72e-4d3d-b1ff-d91fc7b22490@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>C</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Scientific Notation</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "c-scientific-notation"
+      },
+      {
+        "id": "fde24489-0317-41c9-83ee-eb6de6224ea0@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>D</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Units Used in Science</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "d-units-used-in-science"
+      },
+      {
+        "id": "73d49c7c-b8ec-4bb4-a3e8-2fdf9acdf2b3@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>E</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Some Useful Constants for Astronomy</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "e-some-useful-constants-for-astronomy"
+      },
+      {
+        "id": "b88f5bbe-31c9-4a24-8920-0c55689a6142@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>F</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Physical and Orbital Data for the Planets</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "f-physical-and-orbital-data-for-the-planets"
+      },
+      {
+        "id": "bc5da890-ed3e-44f7-a950-26bd9074ca62@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>G</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Selected Moons of the Planets</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "g-selected-moons-of-the-planets"
+      },
+      {
+        "id": "24e32afd-b542-4ca3-a516-455a66ac7900@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>H</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Future Total Eclipses</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "h-future-total-eclipses"
+      },
+      {
+        "id": "d648a9b8-e2a5-4b2d-8979-1a075cb91899@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>I</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nearest Stars, Brown Dwarfs, and White Dwarfs</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "i-the-nearest-stars-brown-dwarfs-and-white-dwarfs"
+      },
+      {
+        "id": "ab019339-b032-49cc-93e8-7e46f704a554@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>J</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Brightest Twenty Stars</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "j-the-brightest-twenty-stars"
+      },
+      {
+        "id": "55ecd3c3-0cdc-482c-8e2f-ec853554054d@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>K</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Chemical Elements</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "k-the-chemical-elements"
+      },
+      {
+        "id": "0e15f0fc-0d77-4a0b-8b70-cfdffc87b73f@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>L</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Constellations</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "l-the-constellations"
+      },
+      {
+        "id": "f97dbe3b-b6e5-45c1-a243-a0afa8c7b95e@",
+        "title": "<span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>M</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Star Chart and Sky Event Resources</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "appendix",
+        "slug": "m-star-chart-and-sky-event-resources"
+      },
+      {
+        "id": "6d5a1a4f-46ab-51f0-8387-cc7bbe5f0041@24525b6",
+        "title": "<span class=\"os-text\">Index</span>",
+        "toc_type": "book-content",
+        "toc_target_type": "index",
+        "slug": "index"
+      }
+    ],
+    "slug": "astronomy-2e"
+  },
+  "slug": "astronomy-2e",
+  "id": "4c29f9e5-a53d-42c0-bdb5-091990527d79",
+  "version": "24525b6",
+  "license": {
+    "url": "http://creativecommons.org/licenses/by/4.0/",
+    "name": "Creative Commons Attribution License"
+  },
+  "language": "en",
+  "content": "<html xmlns=\"http://www.w3.org/1999/xhtml\">\n  <head>\n    <title>Table of Contents</title>\n  </head>\n  <body><nav id=\"toc\"><h1 class=\"os-toc-title\">Contents</h1>\n<ol>\n  <li class=\"os-toc-preface\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b795b4f7-3318-4419-a338-8f5eeb0874ee\" data-toc-type=\"book-content\" data-toc-target-type=\"preface\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b795b4f7-3318-4419-a338-8f5eeb0874ee.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Preface</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>1</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Science and the Universe: A Brief Tour</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ff8e6ee8-8a50-4756-b95e-c3b8e803622b\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ff8e6ee8-8a50-4756-b95e-c3b8e803622b.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Introduction</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7f11b6c9-3774-45f2-89e7-65c0196f6c29\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7f11b6c9-3774-45f2-89e7-65c0196f6c29.xhtml\">\n    <span class=\"os-number\">1.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nature of Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c2150b0b-4881-42c7-83b2-ad766c79d36a\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c2150b0b-4881-42c7-83b2-ad766c79d36a.xhtml\">\n    <span class=\"os-number\">1.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nature of Science</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8b5ce726-e912-4fcd-aacf-e35aaafb9839\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8b5ce726-e912-4fcd-aacf-e35aaafb9839.xhtml\">\n    <span class=\"os-number\">1.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Laws of Nature</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_6d1abd05-a7d8-44c0-acd0-b5b97b3f771b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6d1abd05-a7d8-44c0-acd0-b5b97b3f771b.xhtml\">\n    <span class=\"os-number\">1.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Numbers in Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_72f7108d-f806-4f54-80ac-eed5976266e2\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:72f7108d-f806-4f54-80ac-eed5976266e2.xhtml\">\n    <span class=\"os-number\">1.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Consequences of Light Travel Time</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_206e426a-3d8f-4832-80dd-189b03869a34\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:206e426a-3d8f-4832-80dd-189b03869a34.xhtml\">\n    <span class=\"os-number\">1.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Tour of the Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_abd4b491-1fd8-418f-8a46-c0c9f96df944\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:abd4b491-1fd8-418f-8a46-c0c9f96df944.xhtml\">\n    <span class=\"os-number\">1.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Universe on the Large Scale</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_15fa90be-da2d-48d6-bae9-f3b84d1d3960\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:15fa90be-da2d-48d6-bae9-f3b84d1d3960.xhtml\">\n    <span class=\"os-number\">1.8</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Universe of the Very Small</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bc9a9cec-f111-457a-8360-f3dfcdbfa410\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bc9a9cec-f111-457a-8360-f3dfcdbfa410.xhtml\">\n    <span class=\"os-number\">1.9</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Conclusion and a Beginning</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-1\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b509e547-2c22-5620-9896-032cf5ffd458.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>2</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Observing the Sky: The Birth of Astronomy</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_5669c796-2b05-4a8f-96ac-85939b9b32af\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5669c796-2b05-4a8f-96ac-85939b9b32af.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8c5081ca-2ce9-44b9-8491-bfa4d6948d6e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8c5081ca-2ce9-44b9-8491-bfa4d6948d6e.xhtml\">\n    <span class=\"os-number\">2.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Sky Above</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_3eb6f7c7-5832-4824-b71b-2fa5c5859cb6\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3eb6f7c7-5832-4824-b71b-2fa5c5859cb6.xhtml\">\n    <span class=\"os-number\">2.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Ancient Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_3e7849d9-bda2-4f03-8517-953f63735a69\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3e7849d9-bda2-4f03-8517-953f63735a69.xhtml\">\n    <span class=\"os-number\">2.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Astrology and Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0fa12f98-6991-469f-9e81-e518d4b1507b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0fa12f98-6991-469f-9e81-e518d4b1507b.xhtml\">\n    <span class=\"os-number\">2.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Birth of Modern Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-2\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1d5e084d-726a-5f29-90e3-b8320f12a954.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-3\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d12fe360-e8e0-5690-af42-30f17b29cb3d.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-4\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e24ee7bd-d21b-5af6-a665-f2934ef40c38.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-5\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e5b6912f-7333-57c8-b7af-c93673a27487.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-6\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bf884580-f8b4-5cac-83be-71d8be3b7a38.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-7\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:942be1a5-3d38-5106-9294-bc821ded82f7.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-8\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b54556fb-cfc3-5575-ac76-78f763cde267.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>3</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Orbits and Gravity</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e2171dce-08e7-4d5d-9f87-ae6d454b6831\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e2171dce-08e7-4d5d-9f87-ae6d454b6831.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_47523a07-81ed-49ea-907c-775a77830d8f\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:47523a07-81ed-49ea-907c-775a77830d8f.xhtml\">\n    <span class=\"os-number\">3.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Laws of Planetary Motion</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8dc7024f-0626-4a47-9ddb-34ecd15db2f6\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8dc7024f-0626-4a47-9ddb-34ecd15db2f6.xhtml\">\n    <span class=\"os-number\">3.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Newton’s Great Synthesis</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b601e378-6e52-49c0-a085-29e17a7763bc\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b601e378-6e52-49c0-a085-29e17a7763bc.xhtml\">\n    <span class=\"os-number\">3.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Newton’s Universal Law of Gravitation</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e2c6b1d7-f6ec-4586-9648-770769fb9b34\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e2c6b1d7-f6ec-4586-9648-770769fb9b34.xhtml\">\n    <span class=\"os-number\">3.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Orbits in the Solar System</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b5a9fa3d-f23f-4c86-9ed9-50bfc39fd05b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b5a9fa3d-f23f-4c86-9ed9-50bfc39fd05b.xhtml\">\n    <span class=\"os-number\">3.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Motions of Satellites and Spacecraft</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_2b0e50b7-cacc-4a71-8f1b-6b3151fa8219\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2b0e50b7-cacc-4a71-8f1b-6b3151fa8219.xhtml\">\n    <span class=\"os-number\">3.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Gravity with More Than Two Bodies</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-9\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4848f68c-234e-56ef-af32-f32662b23a3f.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-10\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6a236ece-02df-53bd-89a7-f1dd3c3a69db.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-11\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e7f667c6-c2fd-543b-88b4-0d0d04254e96.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-12\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:281cb692-f479-53cf-a654-25fa863a0e37.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-13\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:189047a9-c2a9-5cc6-9b4c-13b792ee0a48.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-14\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1154892f-55a9-5e47-8080-6a7916fb2b0f.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-15\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f306f90d-c4ce-57f2-9e85-9c65c99eefa3.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>4</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Earth, Moon, and Sky</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_1620756f-04bc-4173-b549-e693ce6e573f\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1620756f-04bc-4173-b549-e693ce6e573f.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_2137756f-bba9-4571-b15d-d99af6911ce8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2137756f-bba9-4571-b15d-d99af6911ce8.xhtml\">\n    <span class=\"os-number\">4.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Earth and Sky</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_1fa4ebbd-7de6-4b35-8b96-1ea6538d10f7\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1fa4ebbd-7de6-4b35-8b96-1ea6538d10f7.xhtml\">\n    <span class=\"os-number\">4.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Seasons</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ff0d0421-83f7-42ce-a604-e3820ebafd76\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ff0d0421-83f7-42ce-a604-e3820ebafd76.xhtml\">\n    <span class=\"os-number\">4.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Keeping Time</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b1642146-c688-4668-abcb-897b128aefe6\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b1642146-c688-4668-abcb-897b128aefe6.xhtml\">\n    <span class=\"os-number\">4.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Calendar</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_4fd1d099-cf07-41a5-ac1a-236f3d2db0eb\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4fd1d099-cf07-41a5-ac1a-236f3d2db0eb.xhtml\">\n    <span class=\"os-number\">4.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Phases and Motions of the Moon</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c309faea-c9aa-4070-89a6-efbba3482901\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c309faea-c9aa-4070-89a6-efbba3482901.xhtml\">\n    <span class=\"os-number\">4.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Ocean Tides and the Moon</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e6b95fa8-0f58-47c0-b3fa-cb82c29696d9\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e6b95fa8-0f58-47c0-b3fa-cb82c29696d9.xhtml\">\n    <span class=\"os-number\">4.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Eclipses of the Sun and Moon</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-16\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1e730129-9750-5236-be77-415ec42c777f.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-17\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:50e253f2-9b38-5b67-82f7-9f5f5e01c474.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-18\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f76807e5-aadb-5440-83b3-7cef84e8f21e.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-19\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:abe57d4e-e592-54a3-b05f-3ce24f4aff18.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-20\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:19efc8be-1fef-5e02-837d-a59b2da0f3b1.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-21\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e064665e-04c3-586e-9096-ce1cb70db09a.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-22\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:078c6c60-e701-5fc6-8472-45fc6b91939f.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>5</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Radiation and Spectra</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bc5ce180-f2b3-4469-a882-22bf96435c99\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bc5ce180-f2b3-4469-a882-22bf96435c99.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_badbbab4-54ea-49f8-834b-4762fc4b7e35\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:badbbab4-54ea-49f8-834b-4762fc4b7e35.xhtml\">\n    <span class=\"os-number\">5.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Behavior of Light</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_15eec1a9-5e3c-4e2b-abac-8cd61748d4a0\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:15eec1a9-5e3c-4e2b-abac-8cd61748d4a0.xhtml\">\n    <span class=\"os-number\">5.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Electromagnetic Spectrum</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_1f92a120-370a-4547-b14e-a3df3ce6f083\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1f92a120-370a-4547-b14e-a3df3ce6f083.xhtml\">\n    <span class=\"os-number\">5.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Spectroscopy in Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_22d9d199-7c88-418f-92bd-6cb72d0e1a53\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:22d9d199-7c88-418f-92bd-6cb72d0e1a53.xhtml\">\n    <span class=\"os-number\">5.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Structure of the Atom</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_9d3d546b-fc92-410c-a9cc-5e084fdb4b62\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9d3d546b-fc92-410c-a9cc-5e084fdb4b62.xhtml\">\n    <span class=\"os-number\">5.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Formation of Spectral Lines</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_9d6442f2-71bf-4ed3-9a37-1723bb846e0e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9d6442f2-71bf-4ed3-9a37-1723bb846e0e.xhtml\">\n    <span class=\"os-number\">5.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Doppler Effect</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-23\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:45103869-56cc-5290-a01c-4589dbb92bd4.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-24\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3fdb800c-d358-58ce-97d3-332101c926f9.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-25\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ac348c37-facc-5204-9ea3-33f8360a2641.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-26\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3d2901ff-5e44-53d2-a035-5b920a406e15.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-27\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9fbdcef4-4417-5477-b51b-dded5adedc8a.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-28\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:af242728-c240-5845-8615-f0f37b36cdd1.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-29\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c41b30a6-cbc9-5948-9ee2-2f0f2915b457.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>6</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Astronomical Instruments</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bd9d6fca-fd83-4112-9379-482f40364ae7\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bd9d6fca-fd83-4112-9379-482f40364ae7.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7c547388-eced-47de-80c9-4826b072356e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7c547388-eced-47de-80c9-4826b072356e.xhtml\">\n    <span class=\"os-number\">6.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Telescopes</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_cbd1efb7-998a-4672-9337-ba9ecf4f8a8d\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cbd1efb7-998a-4672-9337-ba9ecf4f8a8d.xhtml\">\n    <span class=\"os-number\">6.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Telescopes Today</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_558682b0-2683-4513-a52e-beddbd32e4b5\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:558682b0-2683-4513-a52e-beddbd32e4b5.xhtml\">\n    <span class=\"os-number\">6.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Visible-Light Detectors and Instruments</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_99df183c-aa08-41b0-b02e-bb641d304cb9\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:99df183c-aa08-41b0-b02e-bb641d304cb9.xhtml\">\n    <span class=\"os-number\">6.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Radio Telescopes</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ae35cefe-bf23-40b0-97a8-d174c341e5d8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ae35cefe-bf23-40b0-97a8-d174c341e5d8.xhtml\">\n    <span class=\"os-number\">6.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Observations outside Earth’s Atmosphere</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f9b9b592-b963-46ef-92bf-2feb6c600154\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f9b9b592-b963-46ef-92bf-2feb6c600154.xhtml\">\n    <span class=\"os-number\">6.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Future of Large Telescopes</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-30\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:64294cdd-006f-57dd-b017-d00b533d9286.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-31\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:909579e0-cfb9-5e44-8c9e-19e436e21ba8.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-32\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:230ef1dc-e60f-519e-bd57-eb79d71780ea.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-33\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c7756378-900b-52f0-84cf-4a81c3909247.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-34\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f81a1d22-93c5-57a8-8881-c8f98ed43cd1.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-35\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:082d1f66-6f3b-516f-b96b-997ee8a49a39.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-36\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:25eec6f7-dc13-5740-9061-e61b73bf70fa.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>7</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Other Worlds: An Introduction to the Solar System</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0bb91d10-14bd-49f7-ae1c-d97d421465b6\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0bb91d10-14bd-49f7-ae1c-d97d421465b6.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c9239bd9-a44b-4187-a3f9-d0a5511b45e4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c9239bd9-a44b-4187-a3f9-d0a5511b45e4.xhtml\">\n    <span class=\"os-number\">7.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Overview of Our Planetary System</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_89bccab6-a207-484d-95ac-e59f72e0a4f8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:89bccab6-a207-484d-95ac-e59f72e0a4f8.xhtml\">\n    <span class=\"os-number\">7.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Composition and Structure of Planets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_9e21231f-4dd5-4589-87a4-f0abd02bde90\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9e21231f-4dd5-4589-87a4-f0abd02bde90.xhtml\">\n    <span class=\"os-number\">7.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Dating Planetary Surfaces</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_777e7e4d-3bf1-4488-b693-d43f89c58994\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:777e7e4d-3bf1-4488-b693-d43f89c58994.xhtml\">\n    <span class=\"os-number\">7.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Origin of the Solar System</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-37\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:41d86913-b0ee-5bcb-a096-c48c2128ade3.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-38\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:703f5a6e-46c4-5ba0-abe0-36f917d24c3d.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-39\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:44040322-e902-5bd1-aa34-0f78bd003da1.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-40\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:dc293ed0-c6e9-59bc-ace0-4dfc31c9c7f5.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-41\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cac74f3d-01eb-52d3-94ac-02ce58cd63db.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-42\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8408f298-1313-54ee-b85c-fe3c5cb0905a.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-43\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3c297860-bb8c-536b-b2d6-7ff39013e76e.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>8</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Earth as a Planet</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_05a1c8d2-7400-4b6a-ada6-c3179952f725\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:05a1c8d2-7400-4b6a-ada6-c3179952f725.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7c4fae08-3cc6-4e08-9ee0-12158c0f3071\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7c4fae08-3cc6-4e08-9ee0-12158c0f3071.xhtml\">\n    <span class=\"os-number\">8.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Global Perspective</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_06448fca-ae6c-4146-a3e1-b13d8c765c63\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:06448fca-ae6c-4146-a3e1-b13d8c765c63.xhtml\">\n    <span class=\"os-number\">8.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Earth’s Crust</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c5fa6993-c0ee-45f0-ab80-c983b0677452\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c5fa6993-c0ee-45f0-ab80-c983b0677452.xhtml\">\n    <span class=\"os-number\">8.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Earth’s Atmosphere</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f9261cd1-436c-498c-aa22-b81749400913\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f9261cd1-436c-498c-aa22-b81749400913.xhtml\">\n    <span class=\"os-number\">8.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Life, Chemical Evolution, and Climate Change</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b90e376a-c576-4e98-88fc-de2b19526a40\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b90e376a-c576-4e98-88fc-de2b19526a40.xhtml\">\n    <span class=\"os-number\">8.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Cosmic Influences on the Evolution of Earth</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-44\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:68c114b9-eb8e-55f2-8a77-c6d7061d7482.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-45\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7e1a7949-e011-51ca-9d7a-3ddbeeeed1c1.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-46\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:67713eb9-4cc8-56a5-8e30-64b25f3529e9.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-47\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:135ce91b-37d2-5fcb-b46d-56cd0baea009.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-48\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:13a07c5b-a9e3-5c02-8411-81427dcfb583.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-49\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:dd9f8118-1801-58a0-8738-b6f9d73ae983.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-50\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:477a1fcc-2d06-5bfb-b6e1-c7220a5a4d16.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>9</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Cratered Worlds</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f5930002-07c4-4bec-8e25-f3ad35de6963\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f5930002-07c4-4bec-8e25-f3ad35de6963.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_fa6f6f04-2ea7-4c0a-b792-565198157034\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:fa6f6f04-2ea7-4c0a-b792-565198157034.xhtml\">\n    <span class=\"os-number\">9.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">General Properties of the Moon</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_eea4b9d8-6b59-4040-90e8-fead7b28668b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:eea4b9d8-6b59-4040-90e8-fead7b28668b.xhtml\">\n    <span class=\"os-number\">9.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Lunar Surface</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_07ca43bf-5858-4ac3-aa7a-d1fd7992fffe\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:07ca43bf-5858-4ac3-aa7a-d1fd7992fffe.xhtml\">\n    <span class=\"os-number\">9.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Impact Craters</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f11291b8-079b-49fa-a302-4139c51133f9\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f11291b8-079b-49fa-a302-4139c51133f9.xhtml\">\n    <span class=\"os-number\">9.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Origin of the Moon</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c4fdaa69-9e6a-436c-a27a-d7e2cf95e45c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c4fdaa69-9e6a-436c-a27a-d7e2cf95e45c.xhtml\">\n    <span class=\"os-number\">9.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Mercury</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-51\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:43b954f4-f0e3-5b5b-8818-e6c07c464391.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-52\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4d6aab28-4a1d-53af-9630-834c3d61bbe6.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-53\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:232b4c9e-030a-59be-b0a3-1124c3989a16.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-54\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:38d0acbe-c050-5c95-b7f6-633128fd7ee3.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-55\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5fa50daf-30c1-5e02-a08b-b56ff04c0b80.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-56\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2e6f82ba-56f4-5700-93e5-be3a4f1d3c05.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-57\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2bc53836-6b9a-54ce-a207-313e888a18d6.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>10</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Earthlike Planets: Venus and Mars</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bd3a9cb6-eecc-42fb-9626-6bc145004074\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bd3a9cb6-eecc-42fb-9626-6bc145004074.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c76a2699-5934-4efd-b059-3213342d048c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c76a2699-5934-4efd-b059-3213342d048c.xhtml\">\n    <span class=\"os-number\">10.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nearest Planets: An Overview</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e10c1a16-d06c-4057-8813-29ae446efe94\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e10c1a16-d06c-4057-8813-29ae446efe94.xhtml\">\n    <span class=\"os-number\">10.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Geology of Venus</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_41d0c477-4230-42e8-a1b0-ba1317d9b909\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:41d0c477-4230-42e8-a1b0-ba1317d9b909.xhtml\">\n    <span class=\"os-number\">10.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Massive Atmosphere of Venus</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_93c3c498-3673-4622-bdb2-7db24243affa\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:93c3c498-3673-4622-bdb2-7db24243affa.xhtml\">\n    <span class=\"os-number\">10.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Geology of Mars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d163b409-95d7-49e2-a04c-9dcd5e373719\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d163b409-95d7-49e2-a04c-9dcd5e373719.xhtml\">\n    <span class=\"os-number\">10.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Water and Life on Mars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_db6df2ee-5f21-4089-b8b8-df88a87480e9\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:db6df2ee-5f21-4089-b8b8-df88a87480e9.xhtml\">\n    <span class=\"os-number\">10.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Divergent Planetary Evolution</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-58\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9969772a-e0fa-5bde-aac1-f41c43567ccf.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-59\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e0e9166b-91b2-5446-9567-7e135e6a2573.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-60\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8dcbd0a4-8449-58dd-ad02-86f84e085191.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-61\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e9cb534d-6f30-569d-b318-85e1dfa72151.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-62\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:79bee2b6-021c-543d-8686-304d26ea7732.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-63\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:92c96bdf-c2fa-5994-83a3-7a02b96ee531.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-64\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f130004d-c7bd-544d-9ecd-e93ac8957b43.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>11</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Giant Planets</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_24137f9b-61e6-48d5-8ea1-e6fe7fc644d3\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:24137f9b-61e6-48d5-8ea1-e6fe7fc644d3.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d9cfd957-5241-4611-abff-426e7b4f7a0c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d9cfd957-5241-4611-abff-426e7b4f7a0c.xhtml\">\n    <span class=\"os-number\">11.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Exploring the Outer Planets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_139674ba-d381-46a3-b07e-50d0fca52b12\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:139674ba-d381-46a3-b07e-50d0fca52b12.xhtml\">\n    <span class=\"os-number\">11.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Giant Planets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8215f9ce-0a31-4c2e-a6de-bbd5931d229a\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8215f9ce-0a31-4c2e-a6de-bbd5931d229a.xhtml\">\n    <span class=\"os-number\">11.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Atmospheres of the Giant Planets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-65\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5883744c-25a3-5d03-a5f7-1d992312307a.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-66\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ac350723-8733-56de-a7dd-8a9b6c45926d.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-67\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3d16efb7-b2ef-5366-920e-dd4aedc5e40c.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-68\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:176d2cf7-2a5e-5e2b-a888-00276d8b2292.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-69\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:66f15fd3-ae24-5a6e-86bd-fd11f22e9934.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-70\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:84e4ec2b-6ec5-5e6f-b248-82ab77d0d42b.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-71\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:eba8a0a9-3b27-5049-a92d-42181436b9c9.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>12</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Rings, Moons, and Pluto</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_760cf33c-7669-4f5f-a68e-e74a63d3731f\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:760cf33c-7669-4f5f-a68e-e74a63d3731f.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_a03c22a2-3d5b-4ffc-a773-71bf1c98b7f0\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a03c22a2-3d5b-4ffc-a773-71bf1c98b7f0.xhtml\">\n    <span class=\"os-number\">12.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Ring and Moon Systems Introduced</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0bf21b5e-5915-4804-b7a9-ef67fef5c7e8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0bf21b5e-5915-4804-b7a9-ef67fef5c7e8.xhtml\">\n    <span class=\"os-number\">12.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Galilean Moons of Jupiter</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bdc41f58-f869-444a-b939-9c73c0a48d15\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bdc41f58-f869-444a-b939-9c73c0a48d15.xhtml\">\n    <span class=\"os-number\">12.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Titan and Triton</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_6e41304f-cdf5-4a3a-b5f1-0fd49bd85023\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6e41304f-cdf5-4a3a-b5f1-0fd49bd85023.xhtml\">\n    <span class=\"os-number\">12.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Pluto and Charon</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8b8a7842-b3fd-4fda-aa7a-8fa137a1dc42\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8b8a7842-b3fd-4fda-aa7a-8fa137a1dc42.xhtml\">\n    <span class=\"os-number\">12.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Planetary Rings (and Enceladus)</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-72\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:751a867d-468f-5d74-8701-7bac8ded8408.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-73\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:81ae8c53-8cc3-5d14-b713-8f7975e18068.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-74\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ded490db-11f2-5e36-9ded-d9d1ac792c7e.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-75\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:262989c3-345c-5065-b1b5-8251d54cb9fc.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-76\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0be2ec3a-150f-55a9-9e47-55a22fc6bd6a.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-77\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a1102f2e-5c1a-5252-971d-437f4348e671.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-78\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:983e393d-310c-545e-8f85-1f1b575db409.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>13</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Comets and Asteroids: Debris of the Solar System</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_46f47a00-a325-4985-a7e2-92ac70b2483a\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:46f47a00-a325-4985-a7e2-92ac70b2483a.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_721b4675-43e5-47fc-95ed-0eb06cc49d36\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:721b4675-43e5-47fc-95ed-0eb06cc49d36.xhtml\">\n    <span class=\"os-number\">13.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Asteroids</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b1750def-8849-4ae6-87d0-b7a993fc2c24\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b1750def-8849-4ae6-87d0-b7a993fc2c24.xhtml\">\n    <span class=\"os-number\">13.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Asteroids and Planetary Defense</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0adc3d85-995c-427e-a4d1-c90b6161f1e4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0adc3d85-995c-427e-a4d1-c90b6161f1e4.xhtml\">\n    <span class=\"os-number\">13.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The “Long-Haired” Comets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_9aca755b-b169-427f-b460-894e739504b5\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9aca755b-b169-427f-b460-894e739504b5.xhtml\">\n    <span class=\"os-number\">13.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Origin and Fate of Comets and Related Objects</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-79\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ee20a483-c518-52c7-84dd-53c5d50955cb.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-80\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5443c78b-2d01-5c95-b4dc-b0c776a1a3c5.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-81\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0300c939-9813-5e39-85b6-8c66604a684f.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-82\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0a696104-1fce-503f-9d81-044bfe13970c.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-83\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:84f017eb-f4f2-52ae-bfd0-6e34cef464f6.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-84\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6968b908-3f74-57cc-a5ec-5b8ada55a38c.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-85\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d40e20dc-212e-58d7-9b1c-33ba7d0f89bf.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>14</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Cosmic Samples and the Origin of the Solar System</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_821ee95d-a7c5-44fc-9a15-c6aadaaa8b51\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:821ee95d-a7c5-44fc-9a15-c6aadaaa8b51.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_399c3a6d-5dba-4317-9e4d-51ac95c86e5a\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:399c3a6d-5dba-4317-9e4d-51ac95c86e5a.xhtml\">\n    <span class=\"os-number\">14.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Meteors</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b8fcd786-2d2e-415f-8ce8-a61442d8e6b9\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b8fcd786-2d2e-415f-8ce8-a61442d8e6b9.xhtml\">\n    <span class=\"os-number\">14.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Meteorites: Stones from Heaven</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d3960789-d139-4c88-870e-982093388aa6\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d3960789-d139-4c88-870e-982093388aa6.xhtml\">\n    <span class=\"os-number\">14.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Formation of the Solar System</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_32d4a7d0-c061-4fd7-a687-d698a04da5e4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:32d4a7d0-c061-4fd7-a687-d698a04da5e4.xhtml\">\n    <span class=\"os-number\">14.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Comparison with Other Planetary Systems</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_06733e8f-49db-4a2f-bbe0-0d949d4949a8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:06733e8f-49db-4a2f-bbe0-0d949d4949a8.xhtml\">\n    <span class=\"os-number\">14.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Planetary Evolution</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-86\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f2c38a67-5254-5a4b-b12b-c92bff5622ff.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-87\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:801aa218-797e-5ea8-9f39-e9ca8d63ea0a.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-88\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3596165c-86f0-553e-a80c-b10c00418288.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-89\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:97da3361-f782-544d-ac17-dc54abb290d5.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-90\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9206a42b-f983-5d6b-bf37-e88cfa424f33.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-91\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:dd3a14c6-5063-559d-ba97-8740a218dc6f.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-92\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e6715fba-bde3-585b-ba59-73d60ff49ab1.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>15</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Sun: A Garden-Variety Star</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_da30e85d-e625-4c76-bd12-77270b8d4f9b\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:da30e85d-e625-4c76-bd12-77270b8d4f9b.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_97449e6c-5612-433b-9586-c078970c1a2e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:97449e6c-5612-433b-9586-c078970c1a2e.xhtml\">\n    <span class=\"os-number\">15.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Structure and Composition of the Sun</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f4a8969d-bbef-4f5d-a2ef-fa45a3625aa4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f4a8969d-bbef-4f5d-a2ef-fa45a3625aa4.xhtml\">\n    <span class=\"os-number\">15.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Solar Cycle</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_a20c81bb-271c-4862-b4a8-4bda31bb3a2a\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a20c81bb-271c-4862-b4a8-4bda31bb3a2a.xhtml\">\n    <span class=\"os-number\">15.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Solar Activity above the Photosphere</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_2c84c2af-e198-435e-8402-bdb41fab1954\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2c84c2af-e198-435e-8402-bdb41fab1954.xhtml\">\n    <span class=\"os-number\">15.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Space Weather</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-93\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6456a9eb-3668-5088-9816-89fdc720a7fe.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-94\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b1a77d95-741c-5978-b853-7557efd21766.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-95\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:166a26ce-c73f-5a12-af84-a8df475832c4.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-96\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7cfb20d9-d915-5d4e-8a4b-923194389713.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-97\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5eca84ce-de5b-5611-990a-8becf80b1690.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-98\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:532db4b5-f4e3-5adb-9058-235f91804b87.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-99\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a068ca83-8623-5858-896b-feea89c1663a.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>16</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Sun: A Nuclear Powerhouse</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_3e4a13f1-3aeb-4fe2-b9f5-dc354139c29f\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3e4a13f1-3aeb-4fe2-b9f5-dc354139c29f.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0ac646fb-3bf3-498e-a911-c80b917508a4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0ac646fb-3bf3-498e-a911-c80b917508a4.xhtml\">\n    <span class=\"os-number\">16.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Sources of Sunshine: Thermal and Gravitational Energy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_48c2dc44-40da-465e-b524-0adefbbc1490\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:48c2dc44-40da-465e-b524-0adefbbc1490.xhtml\">\n    <span class=\"os-number\">16.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Mass, Energy, and the Theory of Relativity</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_808fd050-635a-4043-9f03-612a5a799c78\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:808fd050-635a-4043-9f03-612a5a799c78.xhtml\">\n    <span class=\"os-number\">16.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Solar Interior: Theory</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_29321b1a-92b6-46a1-8647-2322d31a2426\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:29321b1a-92b6-46a1-8647-2322d31a2426.xhtml\">\n    <span class=\"os-number\">16.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Solar Interior: Observations</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-100\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d0c0d984-378a-5626-b12b-32e99365878c.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-101\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3bacf7ce-950b-5790-bc13-a37a92242dfe.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-102\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bf2d3b85-46de-55e6-bc81-97f1d701623d.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-103\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:663a2148-7506-5ebe-8447-c9daa5e72aa5.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-104\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ab693c4c-e517-5a06-86fc-a31c90207a73.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-105\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4517f013-95d5-5c26-8a1e-112b033ab135.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-106\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d8e4e089-a21b-52e1-82fc-920c8a001af0.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>17</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Analyzing Starlight</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_9d28d6da-b855-4cfe-b629-54620023f99c\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9d28d6da-b855-4cfe-b629-54620023f99c.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c2e301e8-00d7-40aa-adc6-5074e1780167\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c2e301e8-00d7-40aa-adc6-5074e1780167.xhtml\">\n    <span class=\"os-number\">17.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Brightness of Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ae03b328-30e7-4be5-a3fb-f1ea6f56407e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ae03b328-30e7-4be5-a3fb-f1ea6f56407e.xhtml\">\n    <span class=\"os-number\">17.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Colors of Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d1261637-6e72-43d8-be82-54d3e5a3d1e0\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d1261637-6e72-43d8-be82-54d3e5a3d1e0.xhtml\">\n    <span class=\"os-number\">17.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Spectra of Stars (and Brown Dwarfs)</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_167aaaa5-7530-49bd-b110-21d10d7cd56b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:167aaaa5-7530-49bd-b110-21d10d7cd56b.xhtml\">\n    <span class=\"os-number\">17.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Using Spectra to Measure Stellar Radius, Composition, and Motion</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-107\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:88205381-f8d1-54b0-8a72-b8b3ae25a1e3.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-108\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:097df605-c1ea-55fe-b3ce-8f7e2830b75f.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-109\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d29cc47f-de03-5a77-824e-98bbc9014e01.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-110\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0e05a553-20a1-5b14-aa22-55227e3e6749.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-111\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:40f2b0f0-e7fe-5326-8f4c-acd8ce8ef3d2.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-112\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:14740931-bc9d-5ace-a0de-a97922f5274c.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-113\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:527fedf7-a2f4-5b02-ac43-2f1ce798b4f1.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>18</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Stars: A Celestial Census</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_810ba736-3e15-48e2-9491-cf0f401611c3\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:810ba736-3e15-48e2-9491-cf0f401611c3.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f6dd7bbd-c01f-4c46-b50c-851f6fdedd2e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f6dd7bbd-c01f-4c46-b50c-851f6fdedd2e.xhtml\">\n    <span class=\"os-number\">18.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Stellar Census</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7eb90491-5946-4150-9c21-38c946124a55\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7eb90491-5946-4150-9c21-38c946124a55.xhtml\">\n    <span class=\"os-number\">18.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Measuring Stellar Masses</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7b355f77-984b-4af1-b188-97ddeb9e658b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7b355f77-984b-4af1-b188-97ddeb9e658b.xhtml\">\n    <span class=\"os-number\">18.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Diameters of Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_11581e86-b3c6-45ea-bd3e-0d55a8f12ab8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:11581e86-b3c6-45ea-bd3e-0d55a8f12ab8.xhtml\">\n    <span class=\"os-number\">18.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The H–R Diagram</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-114\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ca417f24-20d5-5db8-aa06-47ecb5b5337f.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-115\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:257f91ab-4f86-5678-b6fd-626c33a8c625.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-116\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5b616c97-75ae-576d-b7f6-fc51ffc3d803.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-117\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:24f74dcc-098e-50e6-8cf1-3cfacb5081f0.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-118\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a615a27f-d0ff-5328-a49d-0c06d6140d2f.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-119\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:896598be-427e-5031-ac8a-9f411e70580c.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-120\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:76bc7bc4-a224-5422-a638-c13643d92348.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>19</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Celestial Distances</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_1ee1ae44-9a8c-439f-b39d-c385ef80ca3f\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1ee1ae44-9a8c-439f-b39d-c385ef80ca3f.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_495b1319-ab2a-46be-a216-f98692a0eb14\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:495b1319-ab2a-46be-a216-f98692a0eb14.xhtml\">\n    <span class=\"os-number\">19.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Fundamental Units of Distance</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e7866b9e-59bd-4e63-a285-58320ddaf41c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e7866b9e-59bd-4e63-a285-58320ddaf41c.xhtml\">\n    <span class=\"os-number\">19.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Surveying the Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bdd59622-7b70-46bd-948f-3651c94d230b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bdd59622-7b70-46bd-948f-3651c94d230b.xhtml\">\n    <span class=\"os-number\">19.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Variable Stars: One Key to Cosmic Distances</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_6956e36d-e32e-4e3d-83d8-ca2a23a411d4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6956e36d-e32e-4e3d-83d8-ca2a23a411d4.xhtml\">\n    <span class=\"os-number\">19.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The H–R Diagram and Cosmic Distances</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-121\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ce0a3b20-d659-544f-be83-6e77a65e69c2.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-122\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:03e3eaa0-feab-55e7-a77b-4e71fac2eb65.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-123\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:27e9dec1-54f7-5d23-b959-724e2c8a06b8.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-124\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b5dc5b9a-8380-58a6-a318-bec37596fde1.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-125\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:741eecab-1f0c-58d5-bf3f-7fd8a40c046d.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-126\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cc3e5d3a-4286-57df-b77c-ff6be961b807.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-127\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ef7880d8-9a61-5bcf-911f-8736919891d0.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>20</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Between the Stars: Gas and Dust in Space</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_73158c18-de2f-4a95-b9cf-3ac65c11cbe0\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:73158c18-de2f-4a95-b9cf-3ac65c11cbe0.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0e4c42c9-c91a-4c41-9ad1-116621dae208\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0e4c42c9-c91a-4c41-9ad1-116621dae208.xhtml\">\n    <span class=\"os-number\">20.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Interstellar Medium</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d202bcaf-7f29-43c8-953d-e716c4785ad2\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d202bcaf-7f29-43c8-953d-e716c4785ad2.xhtml\">\n    <span class=\"os-number\">20.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Interstellar Gas</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_9e1d113d-c083-451f-806a-31b3c54b4a05\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9e1d113d-c083-451f-806a-31b3c54b4a05.xhtml\">\n    <span class=\"os-number\">20.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Cosmic Dust</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_a90879d1-ee17-4595-9d79-8e75038891bf\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a90879d1-ee17-4595-9d79-8e75038891bf.xhtml\">\n    <span class=\"os-number\">20.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Cosmic Rays</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ed257b38-6523-4a4d-a227-24223f6753bc\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ed257b38-6523-4a4d-a227-24223f6753bc.xhtml\">\n    <span class=\"os-number\">20.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Life Cycle of Cosmic Material</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e5591420-f150-4160-8b4a-42087b79794b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e5591420-f150-4160-8b4a-42087b79794b.xhtml\">\n    <span class=\"os-number\">20.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Interstellar Matter around the Sun</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-128\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:994d9837-0441-5cf4-8ddd-b484fc2d892b.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-129\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d66a9927-e3d2-5d11-9574-fce93f368e9c.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-130\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:80647693-4dd6-591c-8b51-8da29be074eb.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-131\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7fc9ccc9-acbf-504e-9698-5784653738c8.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-132\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:670064b4-33bd-5f03-b4cf-852a1779dced.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-133\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e3280c98-5fcd-59c5-b34e-d02a87fdd7aa.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-134\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:90b7c114-d88a-59eb-ac33-d2d826606282.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>21</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Birth of Stars and the Discovery of Planets outside the Solar System</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_a4d25617-b0da-4fe3-8542-322122f7e7d3\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a4d25617-b0da-4fe3-8542-322122f7e7d3.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d0564568-2e7f-4a39-9252-57b7f53c75d4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d0564568-2e7f-4a39-9252-57b7f53c75d4.xhtml\">\n    <span class=\"os-number\">21.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Star Formation</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c80b855e-bbb9-49a4-89ca-cceaa1621efd\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c80b855e-bbb9-49a4-89ca-cceaa1621efd.xhtml\">\n    <span class=\"os-number\">21.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The H–R Diagram and the Study of Stellar Evolution</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e24426f1-be17-4920-9461-8d7d449257df\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e24426f1-be17-4920-9461-8d7d449257df.xhtml\">\n    <span class=\"os-number\">21.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evidence That Planets Form around Other Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c86ab422-c09c-4b54-810c-f1432eb3c342\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c86ab422-c09c-4b54-810c-f1432eb3c342.xhtml\">\n    <span class=\"os-number\">21.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Planets beyond the Solar System: Search and Discovery</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_fa826ec8-d865-4fc5-bbc6-b7643788d709\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:fa826ec8-d865-4fc5-bbc6-b7643788d709.xhtml\">\n    <span class=\"os-number\">21.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Exoplanets Everywhere: What We Are Learning</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b6b6db26-7ae7-4735-a8da-988c26104485\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b6b6db26-7ae7-4735-a8da-988c26104485.xhtml\">\n    <span class=\"os-number\">21.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">New Perspectives on Planet Formation</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-135\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f4a4ae6f-5597-52f8-9e71-549ecebbcad2.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-136\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cbf08b5e-4094-5a43-a70d-02b59a732a31.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-137\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4ab44299-c350-5db4-8382-1ff41e49ed01.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-138\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:27464d3b-a232-545a-928d-8d157e05ff1d.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-139\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:fa50cfee-b017-543e-8ff9-0ef57dbb3764.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-140\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:76a8cf10-692d-58bc-8348-6ee0498b828f.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-141\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:33bfb46d-a5e6-5b7c-a660-de2e59f34678.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>22</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Stars from Adolescence to Old Age</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_46b88c58-3f68-469e-98f0-ed46bc80f5a1\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:46b88c58-3f68-469e-98f0-ed46bc80f5a1.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8a6e3d45-44dc-48f6-8973-d6f95fbcc318\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8a6e3d45-44dc-48f6-8973-d6f95fbcc318.xhtml\">\n    <span class=\"os-number\">22.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evolution from the Main Sequence to Red Giants</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_22c8446c-af88-4319-9a18-fe03a51bd297\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:22c8446c-af88-4319-9a18-fe03a51bd297.xhtml\">\n    <span class=\"os-number\">22.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Star Clusters</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_94219738-96dc-47ef-b1e0-03c9044e8ac6\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:94219738-96dc-47ef-b1e0-03c9044e8ac6.xhtml\">\n    <span class=\"os-number\">22.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Checking Out the Theory</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_780466d0-053e-4f7f-adbd-b0d0dac5c99b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:780466d0-053e-4f7f-adbd-b0d0dac5c99b.xhtml\">\n    <span class=\"os-number\">22.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Further Evolution of Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_a75aea70-4fb6-4d2e-9c29-7d29b55b93ce\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a75aea70-4fb6-4d2e-9c29-7d29b55b93ce.xhtml\">\n    <span class=\"os-number\">22.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Evolution of More Massive Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-142\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4dc35307-7f92-5f80-bafe-5c425415d940.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-143\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9ea0ec75-0219-58db-ae3e-3841a81fb5ed.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-144\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2ce536e8-c640-503f-9bd1-f4bb05aac25d.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-145\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0a281ade-2a97-51cb-9fda-6b9c8eaa947f.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-146\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:eb31344f-3d4a-54ad-a7e4-5d5442dc3f33.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-147\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a1c78acc-8234-5de8-833d-aac0010fccdf.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-148\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e71a3ca1-8a9a-568d-8a14-e942836c823d.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>23</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Death of Stars</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_8e460daa-be2b-47de-9d38-ab4c21865a8a\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8e460daa-be2b-47de-9d38-ab4c21865a8a.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_915e3fbb-30e8-464d-ad0f-5a756d205ea7\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:915e3fbb-30e8-464d-ad0f-5a756d205ea7.xhtml\">\n    <span class=\"os-number\">23.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Death of Low-Mass Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ecaa1a98-d696-4822-b88c-1b8e29502ef6\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ecaa1a98-d696-4822-b88c-1b8e29502ef6.xhtml\">\n    <span class=\"os-number\">23.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evolution of Massive Stars: An Explosive Finish</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_a567ba98-3507-49d5-893c-c05cd42eefa5\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a567ba98-3507-49d5-893c-c05cd42eefa5.xhtml\">\n    <span class=\"os-number\">23.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Supernova Observations</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bfeda56d-0942-4640-9f37-619d208eb106\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bfeda56d-0942-4640-9f37-619d208eb106.xhtml\">\n    <span class=\"os-number\">23.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Pulsars and the Discovery of Neutron Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_3a787454-c556-4633-895a-ff762fbd2b72\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3a787454-c556-4633-895a-ff762fbd2b72.xhtml\">\n    <span class=\"os-number\">23.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Evolution of Binary Star Systems</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_979ea345-05c5-4720-ae29-212ffb3b6ecd\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:979ea345-05c5-4720-ae29-212ffb3b6ecd.xhtml\">\n    <span class=\"os-number\">23.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Mystery of the Gamma-Ray Bursts</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-149\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a6a9561d-a717-5fe0-94e3-61251587ddbf.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-150\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cd03cf4b-2990-5ec5-aa2b-29e12e54bc7f.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-151\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:11f0d91c-53c9-5d31-8614-ea549bf4b2a2.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-152\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f97929a8-b88f-5d5e-a316-d19e29a8ddf1.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-153\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4dd8af71-40b9-57a7-ad3c-8f6800931748.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-154\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6c083955-14b0-53fb-a43b-e46bebe6e519.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-155\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:653362da-ed7c-5c27-98e9-d5001cf1b63c.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>24</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Black Holes and Curved Spacetime</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c58084cd-93fa-48ba-82a5-8bc44de393ed\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c58084cd-93fa-48ba-82a5-8bc44de393ed.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_87febba0-f4df-4096-b9f6-a13ed65deb0f\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:87febba0-f4df-4096-b9f6-a13ed65deb0f.xhtml\">\n    <span class=\"os-number\">24.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Introducing General Relativity</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_3ce9d47d-1953-4522-ad16-0a8c17b4cf92\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3ce9d47d-1953-4522-ad16-0a8c17b4cf92.xhtml\">\n    <span class=\"os-number\">24.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Spacetime and Gravity</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_340339c0-3b54-44c0-929a-7fe8b575a8a2\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:340339c0-3b54-44c0-929a-7fe8b575a8a2.xhtml\">\n    <span class=\"os-number\">24.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Tests of General Relativity</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e42a160d-33cd-413f-ba2e-d23601880762\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e42a160d-33cd-413f-ba2e-d23601880762.xhtml\">\n    <span class=\"os-number\">24.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Time in General Relativity</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_366e559d-50aa-4678-b615-bc6f4f06e5cc\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:366e559d-50aa-4678-b615-bc6f4f06e5cc.xhtml\">\n    <span class=\"os-number\">24.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Black Holes</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0eb920e0-9e34-4761-b92a-369b0a40ae70\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0eb920e0-9e34-4761-b92a-369b0a40ae70.xhtml\">\n    <span class=\"os-number\">24.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Evidence for Black Holes</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b59bbcd2-3e7d-4bf0-8f2d-e2ef9265be3a\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b59bbcd2-3e7d-4bf0-8f2d-e2ef9265be3a.xhtml\">\n    <span class=\"os-number\">24.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Gravitational Wave Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-156\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:29b10d46-33e0-508e-afef-4d74683fa5ef.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-157\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3caa9650-7edc-57cf-88b5-23343b499b7c.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-158\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f1bc374d-f58f-5a95-9144-f81fae834cc8.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-159\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:dbda5721-647d-557f-ad1b-e159f3b05489.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-160\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2655c71b-b0b8-5fa9-8152-01786bba960e.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-161\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1c43497c-8604-5d9a-ade9-240ee3178888.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-162\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9d00c01b-5b3f-527f-876b-57501d36a54f.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>25</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Milky Way Galaxy</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_cfa5edb3-71c8-4593-bcef-efbc4dc2d162\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cfa5edb3-71c8-4593-bcef-efbc4dc2d162.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_80c08cb8-b0ca-49a2-bbb9-87ed85d23745\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:80c08cb8-b0ca-49a2-bbb9-87ed85d23745.xhtml\">\n    <span class=\"os-number\">25.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Architecture of the Galaxy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_e5ae30bd-bea0-482e-aa8d-9031fe0a6de5\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e5ae30bd-bea0-482e-aa8d-9031fe0a6de5.xhtml\">\n    <span class=\"os-number\">25.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Spiral Structure</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_3637e692-0455-46d1-a76d-d5a8a0d48e5c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:3637e692-0455-46d1-a76d-d5a8a0d48e5c.xhtml\">\n    <span class=\"os-number\">25.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Mass of the Galaxy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_5bea3219-4ed3-4eba-99a7-8ccd6a723fba\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5bea3219-4ed3-4eba-99a7-8ccd6a723fba.xhtml\">\n    <span class=\"os-number\">25.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Center of the Galaxy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_42d678ee-f4eb-4208-be35-17206525601f\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:42d678ee-f4eb-4208-be35-17206525601f.xhtml\">\n    <span class=\"os-number\">25.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Stellar Populations in the Galaxy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f84ec82d-1a65-48ac-af23-44256b829a73\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f84ec82d-1a65-48ac-af23-44256b829a73.xhtml\">\n    <span class=\"os-number\">25.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Formation of the Galaxy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-163\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ef40ac9d-e8d0-57fb-8ba0-0cf704b6ec26.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-164\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:63582b1e-74fc-5aac-bb7e-d7cccba6971e.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-165\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5e72fbbd-a368-56bd-a025-b7b7801ec348.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-166\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:87c70239-2b35-5085-beb9-ad470f17cc37.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-167\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5691e613-db9d-529c-b092-0943d7eca099.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-168\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:a3754aed-6890-5b14-82b7-a2cc9686fe8c.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-169\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cc425769-e9a5-50fe-9de2-17f2bfe44436.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>26</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Galaxies</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_1db87beb-ec02-4a18-8f7b-fe500224ba2d\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1db87beb-ec02-4a18-8f7b-fe500224ba2d.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7207bf03-f431-490f-af15-d053f957dddd\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7207bf03-f431-490f-af15-d053f957dddd.xhtml\">\n    <span class=\"os-number\">26.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Discovery of Galaxies</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_2301b05b-62ca-4212-9e3d-b68715f001bf\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2301b05b-62ca-4212-9e3d-b68715f001bf.xhtml\">\n    <span class=\"os-number\">26.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Types of Galaxies</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d46dc34b-84fa-4abc-8716-e237f6a71142\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d46dc34b-84fa-4abc-8716-e237f6a71142.xhtml\">\n    <span class=\"os-number\">26.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Properties of Galaxies</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0fd5bc48-a4a5-4876-83a3-68ea812a662a\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0fd5bc48-a4a5-4876-83a3-68ea812a662a.xhtml\">\n    <span class=\"os-number\">26.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Extragalactic Distance Scale</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_eea58296-1089-4e4d-8805-b0dc4fddea2e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:eea58296-1089-4e4d-8805-b0dc4fddea2e.xhtml\">\n    <span class=\"os-number\">26.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Expanding Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-170\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4cfa89d9-5804-594d-b2e6-1dc4493e6ed7.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-171\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:421c45d7-8c22-5df6-a8e5-c391ab8ca185.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-172\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0d3f6db3-9095-5935-abf7-96bb6e9fd5b6.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-173\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e3d66161-3404-52e6-b1ec-960e49811056.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-174\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e46812a6-2df1-5f13-a38f-630ec6b20557.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-175\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b0d7257b-5143-5fb5-9ed0-9bcd58fa8fa2.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-176\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2950b113-2153-5eb6-84d8-829e3df746be.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>27</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Active Galaxies, Quasars, and Supermassive Black Holes</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c1576760-aaaf-4663-ac75-4b81891a0cf3\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c1576760-aaaf-4663-ac75-4b81891a0cf3.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_976cd1d5-fa37-4496-b3fa-c1bc770bdadd\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:976cd1d5-fa37-4496-b3fa-c1bc770bdadd.xhtml\">\n    <span class=\"os-number\">27.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Quasars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_79e546fb-e10c-4604-9cd4-6d64d9535f8c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:79e546fb-e10c-4604-9cd4-6d64d9535f8c.xhtml\">\n    <span class=\"os-number\">27.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Supermassive Black Holes: What Quasars Really Are</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_6abf3134-2c1b-4e20-a4cd-f91360777a8b\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6abf3134-2c1b-4e20-a4cd-f91360777a8b.xhtml\">\n    <span class=\"os-number\">27.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Quasars as Probes of Evolution in the Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-177\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:db953b77-bb82-5d0d-bbc5-f6766d2835ec.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-178\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:50e8e223-ad29-58bf-97d2-7a92e4582e2e.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-179\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:93026b74-2ccd-53ee-ad9b-5e137c203a7d.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-180\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7b052f40-5897-52f2-bb46-614a0b76c4d1.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-181\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:90dabfb1-5dbf-5a2c-ab12-b7fd81eda98d.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-182\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5f141414-ae50-5925-a59f-af539d6a7bc2.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-183\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:84f2d243-0179-58bc-a9b9-a5c7bf2ce011.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>28</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Evolution and Distribution of Galaxies</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d7f7bff9-fe26-4af6-bb4c-b2869541c71a\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d7f7bff9-fe26-4af6-bb4c-b2869541c71a.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_1e224c17-74f4-4082-988d-13dc5475aeda\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1e224c17-74f4-4082-988d-13dc5475aeda.xhtml\">\n    <span class=\"os-number\">28.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Observations of Distant Galaxies</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_06b43416-8559-4c50-b870-e9fda268bf4e\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:06b43416-8559-4c50-b870-e9fda268bf4e.xhtml\">\n    <span class=\"os-number\">28.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Galaxy Mergers and Active Galactic Nuclei</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_09cab279-1255-4465-b14a-ca893103f2e8\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:09cab279-1255-4465-b14a-ca893103f2e8.xhtml\">\n    <span class=\"os-number\">28.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Distribution of Galaxies in Space</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b063470e-4c67-4956-ac8b-aa08510a414f\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b063470e-4c67-4956-ac8b-aa08510a414f.xhtml\">\n    <span class=\"os-number\">28.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Challenge of Dark Matter</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0553dc16-7f85-4d2b-b6d4-aea5dc9dc4ed\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0553dc16-7f85-4d2b-b6d4-aea5dc9dc4ed.xhtml\">\n    <span class=\"os-number\">28.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Formation and Evolution of Galaxies and Structure in the Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-184\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bf968821-6f45-5540-8580-917d0014491c.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-185\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d5682f8a-cfb8-5094-88a8-587d93694e8f.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-186\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0f885ff5-0a57-5f25-9f82-779309f64ffc.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-187\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:620bb949-fa90-5bb8-bf5d-fa6367d2d588.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-188\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:55f9a2f8-0ea7-555b-a185-9f75b05b73f7.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-189\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:8753e1cd-ddc6-5d32-a86e-39a18e656595.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-190\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6062cbac-ddcf-53da-af22-ad651e4a7522.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>29</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">The Big Bang</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_c4987953-c1a0-4df4-8d01-1d0df7ae228f\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:c4987953-c1a0-4df4-8d01-1d0df7ae228f.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_81ac6512-f327-4a65-b2f7-ffa9e2b14302\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:81ac6512-f327-4a65-b2f7-ffa9e2b14302.xhtml\">\n    <span class=\"os-number\">29.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Age of the Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_df0a1d5f-b241-42e4-843f-57fbd3c5c1f1\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:df0a1d5f-b241-42e4-843f-57fbd3c5c1f1.xhtml\">\n    <span class=\"os-number\">29.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">A Model of the Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_aa165ae9-6681-4297-94e1-c013f7cf15fc\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:aa165ae9-6681-4297-94e1-c013f7cf15fc.xhtml\">\n    <span class=\"os-number\">29.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Beginning of the Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_2d06b339-8230-4298-a7e7-72771b1a40a9\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2d06b339-8230-4298-a7e7-72771b1a40a9.xhtml\">\n    <span class=\"os-number\">29.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Cosmic Microwave Background</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_6a24271c-6c9f-4178-92a5-b5e2234f13cf\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6a24271c-6c9f-4178-92a5-b5e2234f13cf.xhtml\">\n    <span class=\"os-number\">29.5</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">What Is the Universe Really Made Of?</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0ff79f0f-13c3-4e5b-8f86-24a52fc009b4\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0ff79f0f-13c3-4e5b-8f86-24a52fc009b4.xhtml\">\n    <span class=\"os-number\">29.6</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Inflationary Universe</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0cb5d17a-1dff-44d4-af38-803d675f303c\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0cb5d17a-1dff-44d4-af38-803d675f303c.xhtml\">\n    <span class=\"os-number\">29.7</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Anthropic Principle</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-191\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1c536721-7310-56cb-b6bf-a324dc3a56b8.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-192\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:25ce4e91-85a4-5442-bfaa-91c3f8a3e1e0.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-193\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b29c0a00-b577-5fbf-9add-5b51b076ab6a.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-194\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:afb23ddb-dcd6-55ce-8c70-2ae2714ee3f0.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-195\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:cc267582-f1e5-51dd-b5ed-d9ed8c86f731.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-196\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:77c7de85-0fd0-5878-81d8-3c1de81be57e.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-197\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e927dd39-8779-5afa-b40c-65ed3e854667.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"chapter\">\n  <span><span class=\"os-number\"><span class=\"os-part-text\">Chapter </span>30</span>\n<span class=\"os-divider\"> </span>\n<span class=\"os-text\" data-type=\"\" itemprop=\"\">Life in the Universe</span>\n\n  </span><ol class=\"os-chapter\">\n    \n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_7ac95c9e-6713-43a4-adf8-c8285882caaa\" data-toc-type=\"book-content\" data-toc-target-type=\"intro\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:7ac95c9e-6713-43a4-adf8-c8285882caaa.xhtml\">\n    <span data-type=\"\" itemprop=\"\" class=\"os-text\">Thinking Ahead</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f302e4d4-b5fd-41bc-8d19-99dcb7e819a2\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f302e4d4-b5fd-41bc-8d19-99dcb7e819a2.xhtml\">\n    <span class=\"os-number\">30.1</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Cosmic Context for Life</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_6e5659bc-b570-4cc3-8078-1eb4acd3b8fc\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6e5659bc-b570-4cc3-8078-1eb4acd3b8fc.xhtml\">\n    <span class=\"os-number\">30.2</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Astrobiology</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_be446a6a-8a98-4999-9ee3-e830ec801ed2\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:be446a6a-8a98-4999-9ee3-e830ec801ed2.xhtml\">\n    <span class=\"os-number\">30.3</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Searching for Life beyond Earth</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_71ee00eb-d39d-437c-9a85-9a8db4309fe3\" data-toc-type=\"book-content\" data-toc-target-type=\"numbered-section\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:71ee00eb-d39d-437c-9a85-9a8db4309fe3.xhtml\">\n    <span class=\"os-number\">30.4</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Search for Extraterrestrial Intelligence</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-198\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:76853ba6-8909-563f-a331-922d6088b270.xhtml\">\n    <span class=\"os-text\">Key Terms</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-199\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:084049c3-342c-57d8-8aa1-fa7a9a4f6665.xhtml\">\n    <span class=\"os-text\">Summary</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-200\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0eaf4ab1-6832-5d1c-a8e9-169487b2a337.xhtml\">\n    <span class=\"os-text\">For Further Exploration</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-201\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:e67b2ba5-dbf5-5266-895c-1bd350187e36.xhtml\">\n    <span class=\"os-text\">Collaborative Group Activities</span>\n  </a>\n</li>\n\n<li class=\"os-toc-composite-chapter\" cnx-archive-shortid=\"\" cnx-archive-uri=\"\" data-toc-type=\"sub-book-tree\">\n  <span><span class=\"os-text\">Exercises</span>\n  \n  </span><ol class=\"os-chapter\">\n    <li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-202\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:2a80add4-220b-5813-8f61-b11d1d5bbf7b.xhtml\">\n    <span class=\"os-text\">Review Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-203\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:9a05fb9c-85f5-5f4a-905f-b6f810d2b77c.xhtml\">\n    <span class=\"os-text\">Thought Questions</span>\n  </a>\n</li>\n\n<li class=\"os-toc-chapter-composite-page\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-204\" data-toc-type=\"book-content\" data-toc-target-type=\"composite-page\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:1b04756d-f897-525d-9c35-fb93e7fcff43.xhtml\">\n    <span class=\"os-text\">Figuring for Yourself</span>\n  </a>\n</li>\n\n  </ol>\n</li>\n\n  </ol>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_4a274b24-cc3d-4264-b5c5-7527026d831e\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:4a274b24-cc3d-4264-b5c5-7527026d831e.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>A</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">How to Study for an Introductory Astronomy Class</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_5828cbfc-03c0-436c-8efe-264a5de96b94\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:5828cbfc-03c0-436c-8efe-264a5de96b94.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>B</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Astronomy Websites, Images, and Apps</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b51ff343-f72e-4d3d-b1ff-d91fc7b22490\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b51ff343-f72e-4d3d-b1ff-d91fc7b22490.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>C</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Scientific Notation</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_fde24489-0317-41c9-83ee-eb6de6224ea0\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:fde24489-0317-41c9-83ee-eb6de6224ea0.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>D</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Units Used in Science</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_73d49c7c-b8ec-4bb4-a3e8-2fdf9acdf2b3\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:73d49c7c-b8ec-4bb4-a3e8-2fdf9acdf2b3.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>E</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Some Useful Constants for Astronomy</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_b88f5bbe-31c9-4a24-8920-0c55689a6142\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:b88f5bbe-31c9-4a24-8920-0c55689a6142.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>F</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Physical and Orbital Data for the Planets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_bc5da890-ed3e-44f7-a950-26bd9074ca62\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:bc5da890-ed3e-44f7-a950-26bd9074ca62.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>G</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Selected Moons of the Planets</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_24e32afd-b542-4ca3-a516-455a66ac7900\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:24e32afd-b542-4ca3-a516-455a66ac7900.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>H</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Future Total Eclipses</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_d648a9b8-e2a5-4b2d-8979-1a075cb91899\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:d648a9b8-e2a5-4b2d-8979-1a075cb91899.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>I</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Nearest Stars, Brown Dwarfs, and White Dwarfs</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_ab019339-b032-49cc-93e8-7e46f704a554\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:ab019339-b032-49cc-93e8-7e46f704a554.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>J</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Brightest Twenty Stars</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_55ecd3c3-0cdc-482c-8e2f-ec853554054d\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:55ecd3c3-0cdc-482c-8e2f-ec853554054d.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>K</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Chemical Elements</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_0e15f0fc-0d77-4a0b-8b70-cfdffc87b73f\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:0e15f0fc-0d77-4a0b-8b70-cfdffc87b73f.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>L</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">The Constellations</span>\n  </a>\n</li>\n\n<li class=\"os-toc-appendix\" cnx-archive-shortid=\"\" cnx-archive-uri=\"page_f97dbe3b-b6e5-45c1-a243-a0afa8c7b95e\" data-toc-type=\"book-content\" data-toc-target-type=\"appendix\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:f97dbe3b-b6e5-45c1-a243-a0afa8c7b95e.xhtml\">\n    <span class=\"os-number\"><span class=\"os-part-text\">Appendix </span>M</span><span class=\"os-divider\"> </span><span data-type=\"\" itemprop=\"\" class=\"os-text\">Star Chart and Sky Event Resources</span>\n  </a>\n</li>\n\n<li class=\"os-toc-index\" cnx-archive-shortid=\"\" cnx-archive-uri=\"composite-page-205\" data-toc-type=\"book-content\" data-toc-target-type=\"index\">\n  <a href=\"./4c29f9e5-a53d-42c0-bdb5-091990527d79@24525b6:6d5a1a4f-46ab-51f0-8387-cc7bbe5f0041.xhtml\">\n    <span class=\"os-text\">Index</span>\n  </a>\n</li>\n\n</ol>\n</nav>\n  </body>\n</html>\n",
+  "repo_schema_version": 1,
+  "style_name": "astronomy",
+  "style_href": "../resources/styles/webview-generic.css"
+}
diff --git a/test/src/data/books.js b/test/src/data/books.js
index 46e50c34f..8359ccc8c 100644
--- a/test/src/data/books.js
+++ b/test/src/data/books.js
@@ -32,7 +32,7 @@ export default {
     "books": [
         {
             "id": 39,
-            "slug": "books/college-algebra",
+            "slug": "v2/pages/39",
             "book_state": "live",
             "title": "College Algebra",
             "subjects": [
diff --git a/test/src/data/resources.js b/test/src/data/resources.js
new file mode 100644
index 000000000..62ee002ff
--- /dev/null
+++ b/test/src/data/resources.js
@@ -0,0 +1,34 @@
+export default [
+    {
+        field: 'Textbook',
+        verbose: 'Textbook'
+    },
+    {
+        field: 'iBooks version',
+        verbose: 'iBooks version'
+    },
+    {
+        field: 'Instructor solution manual',
+        verbose: 'Instructor solution manual'
+    },
+    {
+        field: 'Student solution manual',
+        verbose: 'Student solution manual'
+    },
+    {
+        field: 'Kindle',
+        verbose: 'Kindle'
+    },
+    {
+        field: 'Study guide in online view',
+        verbose: 'Study guide in online view'
+    },
+    {
+        field: 'Assignable',
+        verbose: 'Assignable'
+    },
+    {
+        field: 'Other',
+        verbose: 'Other'
+    }
+];
diff --git a/test/src/pages/errata/errata-form.test.tsx b/test/src/pages/errata/errata-form.test.tsx
new file mode 100644
index 000000000..798e441bc
--- /dev/null
+++ b/test/src/pages/errata/errata-form.test.tsx
@@ -0,0 +1,258 @@
+import React from 'react';
+import {render, screen, waitFor} from '@testing-library/preact';
+import userEvent from '@testing-library/user-event';
+import ErrataForm from '~/pages/errata-form/errata-form';
+import * as UC from '~/contexts/user';
+import MemoryRouter from '~/../../test/helpers/future-memory-router';
+import rexReleaseData from '~/../../test/src/data/astronomy-toc.json';
+
+const mockUseUserContext = jest.spyOn(UC, 'default');
+const mockRexRelease = jest.fn().mockReturnValue(rexReleaseData);
+
+jest.mock('~/models/rex-release', () => ({
+    __esModule: true,
+    default: () => mockRexRelease()
+}));
+
+function Component({bookTitle = 'some-title'}) {
+    return (
+        <MemoryRouter initialEntries={[`/errata/form?book=${bookTitle}`]}>
+            <ErrataForm />
+        </MemoryRouter>
+    );
+}
+
+const user = userEvent.setup();
+
+jest.setTimeout(12000);
+
+describe('errata-form', () => {
+    it('renders; shows other source input when Other source selected', async () => {
+        mockUseUserContext.mockReturnValue({
+            // @ts-expect-error incomplete structure
+            uuid: 1
+        });
+        render(<Component />);
+        await waitFor(() =>
+            expect(screen.getAllByRole('radio', {name: 'Other'}).length).toBe(2)
+        );
+
+        const r = screen.getAllByRole('radio', {name: 'Other'});
+
+        expect(r.length).toBe(2);
+        await user.click(r[0]);
+        await screen.findByRole('textbox', {name: 'other error type'});
+        await user.click(r[1]);
+        await screen.findByRole('textbox', {name: 'other source'});
+        await user.click(screen.getByRole('button', {name: 'Submit'}));
+    });
+    it('tells them to log in if they are not', () => {
+        // @ts-expect-error incomplete structure
+        mockUseUserContext.mockReturnValue({});
+        render(<Component bookTitle="book-title&source" />);
+        screen.getByText('You need to be logged in to submit errata');
+    });
+    it('shows title selector if no title comes in', async () => {
+        mockUseUserContext.mockReturnValue({
+            // @ts-expect-error incomplete structure
+            uuid: 1
+        });
+        render(<Component bookTitle="" />);
+        screen.getByText('What book were you in, again?');
+        await user.click(await screen.findByRole('combobox'));
+        const options = await screen.findAllByRole('option');
+
+        await user.click(options[0]);
+    });
+    it('handles file uploader', async () => {
+        // This covers the revision schedule Nov-Feb
+        jest.useFakeTimers();
+        jest.setSystemTime(new Date('2024-01-07'));
+        render(<Component />);
+        jest.useRealTimers();
+        screen.getByText('November');
+        screen.getByText('February');
+        await user.click(
+            (await screen.findAllByRole('button', {name: 'Add file'}))[0]
+        );
+        const fileInput = document.querySelector(
+            'input[name="file_1"]'
+        ) as HTMLInputElement;
+        const mockFile = new File(['mock content'], 'mock-file.txt', {
+            type: 'text/plain'
+        });
+
+        await userEvent.upload(fileInput, mockFile);
+        await user.click(screen.getByRole('button', {name: 'Clear file'}));
+    });
+    it('handles location parameter and toc selection', async () => {
+        // This covers the revision schedule Mar-Oct
+        jest.useFakeTimers();
+        jest.setSystemTime(new Date('2024-04-07'));
+        render(<Component bookTitle="Astronomy&location=somewhere" />);
+        jest.useRealTimers();
+        screen.getByText('March');
+        screen.getByText('October');
+        const locationInput = (await screen.findByRole('textbox', {
+            name: 'Additional location information, if applicable'
+        })) as HTMLInputElement;
+
+        expect(locationInput.value).toBe('somewhere');
+        // exercise syncValue code in ErrorLocationSelector
+        await user.type(locationInput, ' else');
+        screen.getByText('Where in the book did you find the error?');
+        // exercise toc-selector
+        const select = screen.getByRole<HTMLSelectElement>('listbox');
+        const chapter = screen.getByRole('option', {
+            name: '+ Chapter 2 Observing the Sky: The Birth of Astronomy'
+        });
+
+        await user.click(chapter);
+        expect(chapter.textContent?.substring(0, 1)).toBe('–');
+        const selection = screen.getByRole<HTMLOptionElement>('option', {
+            name: 'Thinking Ahead'
+        });
+
+        await user.selectOptions(select, selection.value);
+        expect(select.value).toBe(selection.value);
+        await user.click(screen.getByRole('button', {name: 'Deselect'}));
+        expect(select.value).toBe('');
+        // Deselect is ok when nothing is selected
+        await user.click(screen.getByRole('button', {name: 'Deselect'}));
+        await user.click(chapter);
+        expect(chapter.textContent?.substring(0, 1)).toBe('+');
+    });
+    it('displays no toc selector when source+location are specified', async () => {
+        render(
+            <Component bookTitle="foo&location=somewhere&source=Assignable" />
+        );
+        expect(
+            (
+                (await screen.findByRole('textbox', {
+                    name: 'Additional location information, if applicable'
+                })) as HTMLInputElement
+            ).value
+        ).toBe('somewhere');
+        expect(
+            screen.queryByText('Where in the book did you find the error?')
+        ).toBeNull();
+    });
+    it('checks errors and sets submitting (errata-form-context)', async () => {
+        render(
+            <Component bookTitle="foo&location=somewhere&source=Assignable" />
+        );
+        await user.click(screen.getByRole('radio', {name: 'Typo'}));
+        await user.click(
+            screen.getByRole('radio', {
+                name: 'Textbook includes print, PDF, and web view'
+            })
+        );
+        await userEvent.type(
+            screen.getByRole('textbox', {
+                name: 'Tell us in detail about the error and your suggestion.'
+            }),
+            'some text'
+        );
+
+        const saveFetch = global.fetch;
+
+        global.fetch = jest.fn().mockRejectedValue('intentional fail');
+        await user.click(screen.getByRole('button', {name: 'Submit'}));
+        expect(global.fetch).toHaveBeenCalled();
+        global.fetch = saveFetch;
+    });
+    it('unpacks json from submission response with id', async () => {
+        render(
+            <Component bookTitle="foo&location=somewhere&source=Assignable" />
+        );
+        await user.click(screen.getByRole('radio', {name: 'Typo'}));
+        await user.click(
+            screen.getByRole('radio', {
+                name: 'Textbook includes print, PDF, and web view'
+            })
+        );
+        await userEvent.type(
+            screen.getByRole('textbox', {
+                name: 'Tell us in detail about the error and your suggestion.'
+            }),
+            'some text'
+        );
+
+        const saveFetch = global.fetch;
+
+        global.fetch = jest.fn().mockResolvedValue({
+            json: () => ({
+                id: 1
+            })
+        });
+        await user.click(screen.getByRole('button', {name: 'Submit'}));
+        expect(global.fetch).toHaveBeenCalled();
+        global.fetch = saveFetch;
+    });
+    it('unpacks json from submission response with no id', async () => {
+        render(
+            <Component bookTitle="foo&location=somewhere&source=Assignable" />
+        );
+        await user.click(screen.getByRole('radio', {name: 'Typo'}));
+        await user.click(
+            screen.getByRole('radio', {
+                name: 'Textbook includes print, PDF, and web view'
+            })
+        );
+        await userEvent.type(
+            screen.getByRole('textbox', {
+                name: 'Tell us in detail about the error and your suggestion.'
+            }),
+            'some text'
+        );
+
+        const saveFetch = global.fetch;
+
+        global.fetch = jest.fn().mockResolvedValue({
+            json: () => ({
+                submitted_by_account_id: [2] // eslint-disable-line camelcase
+            })
+        });
+        await user.click(screen.getByRole('button', {name: 'Submit'}));
+        expect(global.fetch).toHaveBeenCalled();
+        // The banned dialog displays
+        screen.getByRole('dialog');
+        await user.click(screen.getByRole('button', {name: 'close'}));
+        global.fetch = saveFetch;
+    });
+    it('unpacks json from submission response with no id or submitted-by id', async () => {
+        render(
+            <Component bookTitle="foo&location=somewhere&source=Assignable" />
+        );
+        await user.click(screen.getByRole('radio', {name: 'Typo'}));
+        await user.click(
+            screen.getByRole('radio', {
+                name: 'Textbook includes print, PDF, and web view'
+            })
+        );
+        await userEvent.type(
+            screen.getByRole('textbox', {
+                name: 'Tell us in detail about the error and your suggestion.'
+            }),
+            'some text'
+        );
+
+        const fileInput = document.querySelector(
+            'input[name="file_1"]'
+        ) as HTMLInputElement;
+        const mockFile = new File(['mock content'], 'mock-file.txt', {
+            type: 'text/plain'
+        });
+
+        await userEvent.upload(fileInput, mockFile);
+
+        const saveFetch = global.fetch;
+
+        global.fetch = jest.fn().mockResolvedValue({
+            json: () => ({})
+        });
+        await user.click(screen.getByRole('button', {name: 'Submit'}));
+        expect(global.fetch).toHaveBeenCalled();
+        global.fetch = saveFetch;
+    });
+});