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		<id>https://www.explainxkcd.com/wiki/index.php?action=history&amp;feed=atom&amp;title=1300%3A_Galilean_Moons</id>
		<title>1300: Galilean Moons - Revision history</title>
		<link rel="self" type="application/atom+xml" href="https://www.explainxkcd.com/wiki/index.php?action=history&amp;feed=atom&amp;title=1300%3A_Galilean_Moons"/>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;action=history"/>
		<updated>2026-05-23T09:20:28Z</updated>
		<subtitle>Revision history for this page on the wiki</subtitle>
		<generator>MediaWiki 1.30.0</generator>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=367912&amp;oldid=prev</id>
		<title>172.71.150.247: No it isn't</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=367912&amp;oldid=prev"/>
				<updated>2025-03-05T04:46:20Z</updated>
		
		<summary type="html">&lt;p&gt;No it isn&amp;#039;t&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 04:46, 5 March 2025&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l13&quot; &gt;Line 13:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 13:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Io (moon)|Io}}, the innermost and second smallest, says &amp;quot;Hi!&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Io (moon)|Io}}, the innermost and second smallest, says &amp;quot;Hi!&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Europa (moon)|Europa}}, the second-innermost and smallest, says &amp;quot;What's your name?&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Europa (moon)|Europa}}, the second-innermost and smallest, says &amp;quot;What's your name?&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter and the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;(this might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting Co— Q: MOOOOOOO!).&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter and the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Callisto (moon)|Callisto}}, the farthest from Megan, expresses its annoyance at the antics of the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Callisto (moon)|Callisto}}, the farthest from Megan, expresses its annoyance at the antics of the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>172.71.150.247</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=317472&amp;oldid=prev</id>
		<title>FaviFake: Updated name</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=317472&amp;oldid=prev"/>
				<updated>2023-07-08T08:16:51Z</updated>
		
		<summary type="html">&lt;p&gt;Updated name&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 08:16, 8 July 2023&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l20&quot; &gt;Line 20:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 20:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;The title text refers to the unusual {{w|orbital resonance}} among the three inner Galilean moons: Io has an orbital period of about 1.78 Earth days, Europa 3.55 days, and Ganymede 7.15 days, putting them into a 1:2:4 resonance. Callisto, with an orbital period of 16.69 days, is not part of the resonant system. This is illustrated in the animated picture at right, where you may notice that all conjunctions between Io and Europa take place at the &amp;quot;12 o'clock&amp;quot; position and all conjunctions between Europa and Ganymede take place at &amp;quot;6 o'clock&amp;quot; position. You may also notice at the animated picture that, unlike in the fifth and ninth panels of the comic, the three moons are never on the same side of Jupiter at the same time. It is thought that this resonance came about as the moons migrated outward due to {{w|tidal acceleration}}; because the inner moons migrated more quickly, first Io caught up with the 2:1 resonance with Europa and then the two of them evolved outward in lockstep until Europa caught up with the 2:1 resonance with Ganymede. If the Jupiter system were to continue its current evolutionary path for long enough (several billion years), Ganymede would eventually catch up to the 2:1 resonance with Callisto and Callisto would also be trapped in the resonance, becoming the fourth member of a 1:2:4:8 system. The title text expresses Callisto's relief at escaping such a fate, describing the relationship among the other three moons as &amp;quot;their weird ...thing.&amp;quot; Callisto also escapes a common practice among certain groups of humans in which the members greet each other with meaningless phrases, usually an inside joke, whenever they meet, which could also be described as &amp;quot;their weird ...thing.&amp;quot; The word &amp;quot;orbit&amp;quot; could finish Callisto's sentence, as it can also mean a sphere of influence or interest.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;The title text refers to the unusual {{w|orbital resonance}} among the three inner Galilean moons: Io has an orbital period of about 1.78 Earth days, Europa 3.55 days, and Ganymede 7.15 days, putting them into a 1:2:4 resonance. Callisto, with an orbital period of 16.69 days, is not part of the resonant system. This is illustrated in the animated picture at right, where you may notice that all conjunctions between Io and Europa take place at the &amp;quot;12 o'clock&amp;quot; position and all conjunctions between Europa and Ganymede take place at &amp;quot;6 o'clock&amp;quot; position. You may also notice at the animated picture that, unlike in the fifth and ninth panels of the comic, the three moons are never on the same side of Jupiter at the same time. It is thought that this resonance came about as the moons migrated outward due to {{w|tidal acceleration}}; because the inner moons migrated more quickly, first Io caught up with the 2:1 resonance with Europa and then the two of them evolved outward in lockstep until Europa caught up with the 2:1 resonance with Ganymede. If the Jupiter system were to continue its current evolutionary path for long enough (several billion years), Ganymede would eventually catch up to the 2:1 resonance with Callisto and Callisto would also be trapped in the resonance, becoming the fourth member of a 1:2:4:8 system. The title text expresses Callisto's relief at escaping such a fate, describing the relationship among the other three moons as &amp;quot;their weird ...thing.&amp;quot; Callisto also escapes a common practice among certain groups of humans in which the members greet each other with meaningless phrases, usually an inside joke, whenever they meet, which could also be described as &amp;quot;their weird ...thing.&amp;quot; The word &amp;quot;orbit&amp;quot; could finish Callisto's sentence, as it can also mean a sphere of influence or interest.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Later, in [[2264: Satellite]], [[&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;Science Girl&lt;/del&gt;]] was orbited in a similar way by an abandoned satellite.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Later, in [[2264: Satellite]], [[&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;Jill&lt;/ins&gt;]] was orbited in a similar way by an abandoned satellite.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Transcript==&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Transcript==&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>FaviFake</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=314220&amp;oldid=prev</id>
		<title>172.69.70.246: /* Explanation */</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=314220&amp;oldid=prev"/>
				<updated>2023-05-26T22:01:19Z</updated>
		
		<summary type="html">&lt;p&gt;‎&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Explanation&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr style=&quot;vertical-align: top;&quot; lang=&quot;en&quot;&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 22:01, 26 May 2023&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l13&quot; &gt;Line 13:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 13:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Io (moon)|Io}}, the innermost and second smallest, says &amp;quot;Hi!&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Io (moon)|Io}}, the innermost and second smallest, says &amp;quot;Hi!&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Europa (moon)|Europa}}, the second-innermost and smallest, says &amp;quot;What's your name?&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Europa (moon)|Europa}}, the second-innermost and smallest, says &amp;quot;What's your name?&amp;quot;.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter and the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; (this might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;Co-- &lt;/del&gt;Q: MOOOOOOO!).&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter and the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; (this might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;Co— &lt;/ins&gt;Q: MOOOOOOO!).&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Callisto (moon)|Callisto}}, the farthest from Megan, expresses its annoyance at the antics of the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;*{{w|Callisto (moon)|Callisto}}, the farthest from Megan, expresses its annoyance at the antics of the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>172.69.70.246</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=313130&amp;oldid=prev</id>
		<title>FaviFake: /* Explanation */ formating</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=313130&amp;oldid=prev"/>
				<updated>2023-05-14T17:52:32Z</updated>
		
		<summary type="html">&lt;p&gt;‎&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Explanation: &lt;/span&gt; formating&lt;/span&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 17:52, 14 May 2023&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l10&quot; &gt;Line 10:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 10:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;[[File:Galilean moon Laplace resonance animation.gif|thumb|365px|The 1:2:4 {{w|orbital resonance}} of {{w|Ganymede (moon)|Ganymede}}, {{w|Europa (moon)|Europa}}, and {{w|Io (moon)|Io}}]] &amp;lt;!-- DO NOT set the width to anything lower than 365px, as this breaks the animation for some --&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;[[File:Galilean moon Laplace resonance animation.gif|thumb|365px|The 1:2:4 {{w|orbital resonance}} of {{w|Ganymede (moon)|Ganymede}}, {{w|Europa (moon)|Europa}}, and {{w|Io (moon)|Io}}]] &amp;lt;!-- DO NOT set the width to anything lower than 365px, as this breaks the animation for some --&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Megan has somehow acquired a set of {{w|Galilean moons}} similar to the four primary moons of {{w|Jupiter}}. The positions of the moons in the successive panels are reminiscent of the observations made by {{w|Galileo Galilei|Galileo Galilei}} in 1610, which proved for the first time that objects in the heavens could orbit something other than the Earth (today these observations can be reproduced on successive nights by anyone looking at Jupiter with binoculars). As each of Megan's moons passes close to Cueball, it says something different&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;. &lt;/del&gt;{{w|Io (moon)|Io}}, the innermost and second&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;-&lt;/del&gt;smallest, &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;always &lt;/del&gt;says &amp;quot;Hi!&amp;quot; {{w|Europa (moon)|Europa}}, the second-innermost and smallest, &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;always uses the phrase &lt;/del&gt;&amp;quot;What's your name?&amp;quot; {{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;but &lt;/del&gt;the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;Callisto, the farthest from Megan, expresses its annoyance at the antics of the other three moons. &lt;/del&gt;(&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot;MOOOOOOON!&amp;quot; &lt;/del&gt;might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting Co-- Q: MOOOOOOO!)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Megan has somehow acquired a set of {{w|Galilean moons}} similar to the four primary moons of {{w|Jupiter}}. The positions of the moons in the successive panels are reminiscent of the observations made by {{w|Galileo Galilei|Galileo Galilei}} in 1610, which proved for the first time that objects in the heavens could orbit something other than the Earth (today these observations can be reproduced on successive nights by anyone looking at Jupiter with binoculars). As each of Megan's moons passes close to Cueball, it says something different&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;:&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;*&lt;/ins&gt;{{w|Io (moon)|Io}}, the innermost and second smallest, says &amp;quot;Hi!&amp;quot;&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;.&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;*&lt;/ins&gt;{{w|Europa (moon)|Europa}}, the second-innermost and smallest, &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;says &lt;/ins&gt;&amp;quot;What's your name?&amp;quot;&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;.&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;*&lt;/ins&gt;{{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;and &lt;/ins&gt;the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; (&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;this &lt;/ins&gt;might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting Co-- Q: MOOOOOOO!)&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;.&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot;&gt;&amp;#160;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;*{{w|Callisto (moon)|Callisto}}, the farthest from Megan, expresses its annoyance at the antics of the other three moons.&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Because the inner moons orbit Jupiter faster (due to {{w|Kepler's laws of planetary motion#Third law|Kepler's Third Law}}), they pass by Cueball more often: Io ten times, Europa five times, and Ganymede twice over the course of the comic. In fact, the outermost crater-scarred moon &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;{{w|&lt;/del&gt;Callisto &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;(moon)|Callisto}} &lt;/del&gt;appears to have passed its closest approach to Cueball just before the first panel (perhaps before Megan and her retinue had walked up to Cueball) and does not approach Cueball again until the tenth panel. At that point, due to some apparent exertion on Callisto's part, it leaves Megan's orbit and begins to orbit Cueball instead. This process could be seen as analogous to the capture of moons from one planet to another, which can happen in less stable systems than our solar system if two planets were to pass close to each other&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;, &lt;/del&gt;but is mostly just whimsical. The humor derives from attributing human characteristics to the moon Callisto in attempting to escape from the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Because the inner moons orbit Jupiter faster (due to {{w|Kepler's laws of planetary motion#Third law|Kepler's Third Law}}), they pass by Cueball more often: Io ten times, Europa five times, and Ganymede twice over the course of the comic. In fact, the outermost crater-scarred moon Callisto appears to have passed its closest approach to Cueball just before the first panel (perhaps before Megan and her retinue had walked up to Cueball) and does not approach Cueball again until the tenth panel. At that point, due to some apparent exertion on Callisto's part, it leaves Megan's orbit and begins to orbit Cueball instead. This process could be seen as analogous to the capture of moons from one planet to another, which can happen in less stable systems than our solar system if two planets were to pass close to each other but is mostly just whimsical. The humor derives from attributing human characteristics to the moon Callisto in attempting to escape from the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;The title text refers to the unusual {{w|orbital resonance}} among the three inner Galilean moons: Io has an orbital period of about 1.78 Earth days, Europa 3.55 days, and Ganymede 7.15 days, putting them into a 1:2:4 resonance. Callisto, with an orbital period of 16.69 days, is not part of the resonant system. This is illustrated in the animated picture at right, where you may notice that all conjunctions between Io and Europa take place at the &amp;quot;12 o'clock&amp;quot; position and all conjunctions between Europa and Ganymede take place at &amp;quot;6 o'clock&amp;quot; position. You may also notice at the animated picture that, unlike in the fifth and ninth panels of the comic, the three moons are never on the same side of Jupiter at the same time. It is thought that this resonance came about as the moons migrated outward due to {{w|tidal acceleration}}; because the inner moons migrated more quickly, first Io caught up with the 2:1 resonance with Europa and then the two of them evolved outward in lockstep until Europa caught up with the 2:1 resonance with Ganymede. If the Jupiter system were to continue its current evolutionary path for long enough (several billion years), Ganymede would eventually catch up to the 2:1 resonance with Callisto and Callisto would also be trapped in the resonance, becoming the fourth member of a 1:2:4:8 system. The title text expresses Callisto's relief at escaping such a fate, describing the relationship among the other three moons as &amp;quot;their weird ...thing.&amp;quot; Callisto also escapes a common practice among certain groups of humans in which the members greet each other with meaningless phrases, usually an inside joke, whenever they meet, which could also be described as &amp;quot;their weird ...thing.&amp;quot; The word &amp;quot;orbit&amp;quot; could finish Callisto's sentence, as it can also mean a sphere of influence or interest.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;The title text refers to the unusual {{w|orbital resonance}} among the three inner Galilean moons: Io has an orbital period of about 1.78 Earth days, Europa 3.55 days, and Ganymede 7.15 days, putting them into a 1:2:4 resonance. Callisto, with an orbital period of 16.69 days, is not part of the resonant system. This is illustrated in the animated picture at right, where you may notice that all conjunctions between Io and Europa take place at the &amp;quot;12 o'clock&amp;quot; position and all conjunctions between Europa and Ganymede take place at &amp;quot;6 o'clock&amp;quot; position. You may also notice at the animated picture that, unlike in the fifth and ninth panels of the comic, the three moons are never on the same side of Jupiter at the same time. It is thought that this resonance came about as the moons migrated outward due to {{w|tidal acceleration}}; because the inner moons migrated more quickly, first Io caught up with the 2:1 resonance with Europa and then the two of them evolved outward in lockstep until Europa caught up with the 2:1 resonance with Ganymede. If the Jupiter system were to continue its current evolutionary path for long enough (several billion years), Ganymede would eventually catch up to the 2:1 resonance with Callisto and Callisto would also be trapped in the resonance, becoming the fourth member of a 1:2:4:8 system. The title text expresses Callisto's relief at escaping such a fate, describing the relationship among the other three moons as &amp;quot;their weird ...thing.&amp;quot; Callisto also escapes a common practice among certain groups of humans in which the members greet each other with meaningless phrases, usually an inside joke, whenever they meet, which could also be described as &amp;quot;their weird ...thing.&amp;quot; The word &amp;quot;orbit&amp;quot; could finish Callisto's sentence, as it can also mean a sphere of influence or interest.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Later, in [[2264: Satellite]], &lt;del class=&quot;diffchange diffchange-inline&quot;&gt; &lt;/del&gt;[[Science Girl]] was orbited in a similar way by an abandoned satellite.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Later, in [[2264: Satellite]], [[Science Girl]] was orbited in a similar way by an abandoned satellite.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Transcript==&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Transcript==&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>FaviFake</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=299484&amp;oldid=prev</id>
		<title>JLZ0kTC5 at 10:50, 20 November 2022</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=299484&amp;oldid=prev"/>
				<updated>2022-11-20T10:50:37Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: white; color:black; text-align: center;&quot;&gt;Revision as of 10:50, 20 November 2022&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l12&quot; &gt;Line 12:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 12:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Megan has somehow acquired a set of {{w|Galilean moons}} similar to the four primary moons of {{w|Jupiter}}. The positions of the moons in the successive panels are reminiscent of the observations made by {{w|Galileo Galilei|Galileo Galilei}} in 1610, which proved for the first time that objects in the heavens could orbit something other than the Earth (today these observations can be reproduced on successive nights by anyone looking at Jupiter with binoculars). As each of Megan's moons passes close to Cueball, it says something different. {{w|Io (moon)|Io}}, the innermost and second-smallest, always says &amp;quot;Hi!&amp;quot; {{w|Europa (moon)|Europa}}, the second-innermost and smallest, always uses the phrase &amp;quot;What's your name?&amp;quot; {{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter but the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; Callisto, the farthest from Megan, expresses its annoyance at the antics of the other three moons. (&amp;quot;MOOOOOOON!&amp;quot; might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting Co-- Q: MOOOOOOO!)&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Megan has somehow acquired a set of {{w|Galilean moons}} similar to the four primary moons of {{w|Jupiter}}. The positions of the moons in the successive panels are reminiscent of the observations made by {{w|Galileo Galilei|Galileo Galilei}} in 1610, which proved for the first time that objects in the heavens could orbit something other than the Earth (today these observations can be reproduced on successive nights by anyone looking at Jupiter with binoculars). As each of Megan's moons passes close to Cueball, it says something different. {{w|Io (moon)|Io}}, the innermost and second-smallest, always says &amp;quot;Hi!&amp;quot; {{w|Europa (moon)|Europa}}, the second-innermost and smallest, always uses the phrase &amp;quot;What's your name?&amp;quot; {{w|Ganymede (moon)|Ganymede}}, the third moon from Jupiter but the largest in size, interrupts Europa by shouting &amp;quot;MOOOOOON!&amp;quot; Callisto, the farthest from Megan, expresses its annoyance at the antics of the other three moons. (&amp;quot;MOOOOOOON!&amp;quot; might be a reference to an old joke: Q: Knock Knock. A: Who's there? Q: Interrupting Cow. A: Interrupting Co-- Q: MOOOOOOO!)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Because the inner moons orbit Jupiter faster (due to {{w|Kepler's laws of planetary motion#Third law|Kepler's Third Law}}), they pass by Cueball more often: Io ten times, Europa five times, and Ganymede twice over the course of the comic. In fact, the outermost crater-scarred moon {{w|Callisto (moon)|Callisto}} appears to have passed its closest approach to Cueball just before the first panel (perhaps before Megan and her retinue had walked up to Cueball) and does not approach Cueball again until the tenth panel. At that point, due to some apparent exertion on Callisto's part, it leaves Megan's orbit and begins to orbit Cueball instead. This process could be seen as analogous to the capture of moons from one planet to another, which can happen in less stable systems than our solar system if two planets were to pass close to each other, but is mostly just whimsical. The &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;humour &lt;/del&gt;derives from attributing human characteristics to the moon Callisto in attempting to escape from the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Because the inner moons orbit Jupiter faster (due to {{w|Kepler's laws of planetary motion#Third law|Kepler's Third Law}}), they pass by Cueball more often: Io ten times, Europa five times, and Ganymede twice over the course of the comic. In fact, the outermost crater-scarred moon {{w|Callisto (moon)|Callisto}} appears to have passed its closest approach to Cueball just before the first panel (perhaps before Megan and her retinue had walked up to Cueball) and does not approach Cueball again until the tenth panel. At that point, due to some apparent exertion on Callisto's part, it leaves Megan's orbit and begins to orbit Cueball instead. This process could be seen as analogous to the capture of moons from one planet to another, which can happen in less stable systems than our solar system if two planets were to pass close to each other, but is mostly just whimsical. The &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;humor &lt;/ins&gt;derives from attributing human characteristics to the moon Callisto in attempting to escape from the other three moons.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;The title text refers to the unusual {{w|orbital resonance}} among the three inner Galilean moons: Io has an orbital period of about 1.78 Earth days, Europa 3.55 days, and Ganymede 7.15 days, putting them into a 1:2:4 resonance. Callisto, with an orbital period of 16.69 days, is not part of the resonant system. This is illustrated in the animated picture at right, where you may notice that all conjunctions between Io and Europa take place at the &amp;quot;12 o'clock&amp;quot; position and all conjunctions between Europa and Ganymede take place at &amp;quot;6 o'clock&amp;quot; position. You may also notice at the animated picture that, unlike in the fifth and ninth panels of the comic, the three moons are never on the same side of Jupiter at the same time. It is thought that this resonance came about as the moons migrated outward due to {{w|tidal acceleration}}; because the inner moons migrated more quickly, first Io caught up with the 2:1 resonance with Europa and then the two of them evolved outward in lockstep until Europa caught up with the 2:1 resonance with Ganymede. If the Jupiter system were to continue its current evolutionary path for long enough (several billion years), Ganymede would eventually catch up to the 2:1 resonance with Callisto and Callisto would also be trapped in the resonance, becoming the fourth member of a 1:2:4:8 system. The title text expresses Callisto's relief at escaping such a fate, describing the relationship among the other three moons as &amp;quot;their weird ...thing.&amp;quot; Callisto also escapes a common practice among certain groups of humans in which the members greet each other with meaningless phrases, usually an inside joke, whenever they meet, which could also be described as &amp;quot;their weird ...thing.&amp;quot; The word &amp;quot;orbit&amp;quot; could finish Callisto's sentence, as it can also mean a sphere of influence or interest.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;The title text refers to the unusual {{w|orbital resonance}} among the three inner Galilean moons: Io has an orbital period of about 1.78 Earth days, Europa 3.55 days, and Ganymede 7.15 days, putting them into a 1:2:4 resonance. Callisto, with an orbital period of 16.69 days, is not part of the resonant system. This is illustrated in the animated picture at right, where you may notice that all conjunctions between Io and Europa take place at the &amp;quot;12 o'clock&amp;quot; position and all conjunctions between Europa and Ganymede take place at &amp;quot;6 o'clock&amp;quot; position. You may also notice at the animated picture that, unlike in the fifth and ninth panels of the comic, the three moons are never on the same side of Jupiter at the same time. It is thought that this resonance came about as the moons migrated outward due to {{w|tidal acceleration}}; because the inner moons migrated more quickly, first Io caught up with the 2:1 resonance with Europa and then the two of them evolved outward in lockstep until Europa caught up with the 2:1 resonance with Ganymede. If the Jupiter system were to continue its current evolutionary path for long enough (several billion years), Ganymede would eventually catch up to the 2:1 resonance with Callisto and Callisto would also be trapped in the resonance, becoming the fourth member of a 1:2:4:8 system. The title text expresses Callisto's relief at escaping such a fate, describing the relationship among the other three moons as &amp;quot;their weird ...thing.&amp;quot; Callisto also escapes a common practice among certain groups of humans in which the members greet each other with meaningless phrases, usually an inside joke, whenever they meet, which could also be described as &amp;quot;their weird ...thing.&amp;quot; The word &amp;quot;orbit&amp;quot; could finish Callisto's sentence, as it can also mean a sphere of influence or interest.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>JLZ0kTC5</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=282990&amp;oldid=prev</id>
		<title>Vandalbane: Reverted vandalism with User:CRLF/OneClickUndo.js</title>
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				<updated>2022-05-26T19:55:49Z</updated>
		
		<summary type="html">&lt;p&gt;Reverted vandalism with &lt;a href=&quot;/wiki/index.php/User:CRLF/OneClickUndo.js&quot; title=&quot;User:CRLF/OneClickUndo.js&quot;&gt;User:CRLF/OneClickUndo.js&lt;/a&gt;&lt;/p&gt;
&lt;a href=&quot;//www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;amp;diff=282990&amp;amp;oldid=282325&quot;&gt;Show changes&lt;/a&gt;</summary>
		<author><name>Vandalbane</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=282325&amp;oldid=prev</id>
		<title>Donald Trump: Reverted edit by anti-crap user</title>
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				<updated>2022-05-26T19:04:51Z</updated>
		
		<summary type="html">&lt;p&gt;Reverted edit by anti-crap user&lt;/p&gt;
&lt;a href=&quot;//www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;amp;diff=282325&amp;amp;oldid=279641&quot;&gt;Show changes&lt;/a&gt;</summary>
		<author><name>Donald Trump</name></author>	</entry>

	<entry>
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		<title>CRLF: Reverted vandalism with User:CRLF/OneClickUndo.js</title>
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				<updated>2022-05-26T17:45:14Z</updated>
		
		<summary type="html">&lt;p&gt;Reverted vandalism with &lt;a href=&quot;/wiki/index.php/User:CRLF/OneClickUndo.js&quot; title=&quot;User:CRLF/OneClickUndo.js&quot;&gt;User:CRLF/OneClickUndo.js&lt;/a&gt;&lt;/p&gt;
&lt;a href=&quot;//www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;amp;diff=279641&amp;amp;oldid=279046&quot;&gt;Show changes&lt;/a&gt;</summary>
		<author><name>CRLF</name></author>	</entry>

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		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=279046&amp;oldid=prev</id>
		<title>Donald Trump: Reverted edit by anti-crap user</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=279046&amp;oldid=prev"/>
				<updated>2022-05-26T17:25:54Z</updated>
		
		<summary type="html">&lt;p&gt;Reverted edit by anti-crap user&lt;/p&gt;
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		<author><name>Donald Trump</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;diff=266806&amp;oldid=prev</id>
		<title>BetaOS: Undo revision 266801 by 👖🔥 (talk)</title>
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				<updated>2022-05-11T17:48:48Z</updated>
		
		<summary type="html">&lt;p&gt;Undo revision 266801 by &lt;a href=&quot;/wiki/index.php/Special:Contributions/%F0%9F%91%96%F0%9F%94%A5&quot; title=&quot;Special:Contributions/👖🔥&quot;&gt;👖🔥&lt;/a&gt; (&lt;a href=&quot;/wiki/index.php?title=User_talk:%F0%9F%91%96%F0%9F%94%A5&amp;amp;action=edit&amp;amp;redlink=1&quot; class=&quot;new&quot; title=&quot;User talk:👖🔥 (page does not exist)&quot;&gt;talk&lt;/a&gt;)&lt;/p&gt;
&lt;a href=&quot;//www.explainxkcd.com/wiki/index.php?title=1300:_Galilean_Moons&amp;amp;diff=266806&amp;amp;oldid=266801&quot;&gt;Show changes&lt;/a&gt;</summary>
		<author><name>BetaOS</name></author>	</entry>

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