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		<id>https://www.explainxkcd.com/wiki/index.php?action=history&amp;feed=atom&amp;title=3181%3A_Jumping_Frog_Radius</id>
		<title>3181: Jumping Frog Radius - 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=3181%3A_Jumping_Frog_Radius"/>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;action=history"/>
		<updated>2026-05-23T07:34:30Z</updated>
		<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=412330&amp;oldid=prev</id>
		<title>Ozchess: removed sinkhole, grammar fix</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=412330&amp;oldid=prev"/>
				<updated>2026-05-11T23:29:06Z</updated>
		
		<summary type="html">&lt;p&gt;removed sinkhole, grammar fix&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&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 23:29, 11 May 2026&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-l16&quot; &gt;Line 16:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 16:&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;If ''M'' were the mass of the {{w|Earth}}, it would give the Schwarzschild radius for the Earth, which is about 9 mm. (If all of Earth's mass were compressed into a sphere of a bit less than 2&amp;amp;#8239;cm in diameter, it would become a black hole.)&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;If ''M'' were the mass of the {{w|Earth}}, it would give the Schwarzschild radius for the Earth, which is about 9 mm. (If all of Earth's mass were compressed into a sphere of a bit less than 2&amp;amp;#8239;cm in diameter, it would become a black hole.)&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;The comic suggests a &amp;quot;more useful&amp;quot; radius: the ''Jumping Frog radius'' ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;, which is the size of a &amp;quot;planet&amp;quot; such that its gravity keeps a champion {{w|Frog jumping contest|jumping&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;}} {{w|The Celebrated Jumping Frog of Calaveras County|&lt;/del&gt;frog}} from being able to achieve {{w|escape velocity}}. Thus [[Randall]] has instead of ''c'', the 299,792,458&amp;amp;#8239;m/s speed of light, used a much smaller value of 4.5&amp;amp;#8239;m/s, to represent the maximum speed of a jumping frog. It is possible that Randall got that value from [https://www.researchgate.net/publication/5661154_Explosive_Jumping_Extreme_Morphological_and_Physiological_Specializations_of_Australian_Rocket_Frogs_Litoria_nasuta this paper], which on page 179 puts an upper limit on the maximum velocity of adult Australian {{w|striped rocket frog}}s at 4.52&amp;amp;#8239;m/s. (The frog is shown making a &amp;quot;ribbit&amp;quot; sound, which is made by {{w|Pacific tree frog}}s and their relatives in North America and not by rocket frogs, but it's [https://www.imdb.com/list/ls052470723/ widely attributed to frogs all over the world].)&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;The comic suggests a &amp;quot;more useful&amp;quot; radius: the ''Jumping Frog radius'' ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;, which is the size of a &amp;quot;planet&amp;quot; such that its gravity keeps a champion {{w|Frog jumping contest|jumping frog}} from being able to achieve {{w|escape velocity}}. Thus [[Randall]] has instead of ''c'', the 299,792,458&amp;amp;#8239;m/s speed of light, used a much smaller value of 4.5&amp;amp;#8239;m/s, to represent the maximum speed of a jumping frog. It is possible that Randall got that value from [https://www.researchgate.net/publication/5661154_Explosive_Jumping_Extreme_Morphological_and_Physiological_Specializations_of_Australian_Rocket_Frogs_Litoria_nasuta this paper], which on page 179 puts an upper limit on the maximum velocity of adult Australian {{w|striped rocket frog}}s at 4.52&amp;amp;#8239;m/s. (The frog is shown making a &amp;quot;ribbit&amp;quot; sound, which is made by {{w|Pacific tree frog}}s and their relatives in North America and not by rocket frogs, but it's [https://www.imdb.com/list/ls052470723/ widely attributed to frogs all over the world].)&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;it &lt;/del&gt;wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs hopping around in interplanetary space. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;they &lt;/ins&gt;wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs hopping around in interplanetary space. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Ozchess</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407375&amp;oldid=prev</id>
		<title>2601:1C0:8080:3C70:1E7:BFBE:683A:18D1: /* Explanation */</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407375&amp;oldid=prev"/>
				<updated>2026-02-28T01:10:29Z</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;
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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 01:10, 28 February 2026&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;that might be trying to hop away from the Solar System&lt;/del&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;hopping around in interplanetary space&lt;/ins&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>2601:1C0:8080:3C70:1E7:BFBE:683A:18D1</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407342&amp;oldid=prev</id>
		<title>2601:1C0:8080:3C70:1E7:BFBE:683A:18D1: /* Explanation */</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407342&amp;oldid=prev"/>
				<updated>2026-02-27T20:54:23Z</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 20:54, 27 February 2026&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs that might be &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;gravitationally up for grabs&lt;/del&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs that might be &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;trying to hop away from the Solar System&lt;/ins&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>2601:1C0:8080:3C70:1E7:BFBE:683A:18D1</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407322&amp;oldid=prev</id>
		<title>2601:1C0:8080:3C70:10F8:D748:A1E9:ECB3: /* Explanation */</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407322&amp;oldid=prev"/>
				<updated>2026-02-27T10:44:22Z</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 10:44, 27 February 2026&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-l16&quot; &gt;Line 16:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 16:&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;If ''M'' were the mass of the {{w|Earth}}, it would give the Schwarzschild radius for the Earth, which is about 9 mm. (If all of Earth's mass were compressed into a sphere of a bit less than 2&amp;amp;#8239;cm in diameter, it would become a black hole.)&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;If ''M'' were the mass of the {{w|Earth}}, it would give the Schwarzschild radius for the Earth, which is about 9 mm. (If all of Earth's mass were compressed into a sphere of a bit less than 2&amp;amp;#8239;cm in diameter, it would become a black hole.)&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;The comic suggests a more useful radius: the ''Jumping Frog radius'' ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;, which is the size of a &amp;quot;planet&amp;quot; such that its gravity keeps a champion {{w|Frog jumping contest|jumping}} {{w|The Celebrated Jumping Frog of Calaveras County|frog}} from being able to achieve {{w|escape velocity}}. Thus [[Randall]] has instead of ''c'', the 299,792,458&amp;amp;#8239;m/s speed of light, used a much smaller value of 4.5&amp;amp;#8239;m/s, to represent the maximum speed of a jumping frog. It is possible that Randall got that value from [https://www.researchgate.net/publication/5661154_Explosive_Jumping_Extreme_Morphological_and_Physiological_Specializations_of_Australian_Rocket_Frogs_Litoria_nasuta this paper], which on page 179 puts an upper limit on the maximum velocity of adult Australian {{w|striped rocket frog}}s at 4.52&amp;amp;#8239;m/s. (The frog is shown making a &amp;quot;ribbit&amp;quot; sound, which is made by {{w|Pacific tree frog}}s and their relatives in North America and not by rocket frogs, but it's [https://www.imdb.com/list/ls052470723/ widely attributed to frogs all over the world].)&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;The comic suggests a &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot;&lt;/ins&gt;more useful&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;quot; &lt;/ins&gt;radius: the ''Jumping Frog radius'' ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;, which is the size of a &amp;quot;planet&amp;quot; such that its gravity keeps a champion {{w|Frog jumping contest|jumping}} {{w|The Celebrated Jumping Frog of Calaveras County|frog}} from being able to achieve {{w|escape velocity}}. Thus [[Randall]] has instead of ''c'', the 299,792,458&amp;amp;#8239;m/s speed of light, used a much smaller value of 4.5&amp;amp;#8239;m/s, to represent the maximum speed of a jumping frog. It is possible that Randall got that value from [https://www.researchgate.net/publication/5661154_Explosive_Jumping_Extreme_Morphological_and_Physiological_Specializations_of_Australian_Rocket_Frogs_Litoria_nasuta this paper], which on page 179 puts an upper limit on the maximum velocity of adult Australian {{w|striped rocket frog}}s at 4.52&amp;amp;#8239;m/s. (The frog is shown making a &amp;quot;ribbit&amp;quot; sound, which is made by {{w|Pacific tree frog}}s and their relatives in North America and not by rocket frogs, but it's [https://www.imdb.com/list/ls052470723/ widely attributed to frogs all over the world].)&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs that might be &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;floating around in interplanetary space&lt;/del&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore, five Solar System bodies (the Sun and the four giant planets) have gravity wells greater than Earth's, and therefore larger ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; and greater ability to collect any frogs that might be &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;gravitationally up for grabs&lt;/ins&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does accurately explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>2601:1C0:8080:3C70:10F8:D748:A1E9:ECB3</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407313&amp;oldid=prev</id>
		<title>2601:1C0:8080:3C70:10F8:D748:A1E9:ECB3: /* Explanation */</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407313&amp;oldid=prev"/>
				<updated>2026-02-27T03:34:31Z</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;
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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 03:34, 27 February 2026&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius, &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;and &lt;/del&gt;five &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;of them &lt;/del&gt;(the Sun and the four giant planets) have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;than Earth's. If a frog were &lt;/del&gt;to &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;be on &lt;/del&gt;any &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;of those other bodies, it wouldn't &lt;/del&gt;be &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;able to jump away to fall to Earth&lt;/del&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;factually &lt;/del&gt;explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. Furthermore&lt;/ins&gt;, five &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;Solar System bodies &lt;/ins&gt;(the Sun and the four giant planets) have &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;gravity wells greater than Earth's, and therefore larger &lt;/ins&gt;''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;and &lt;/ins&gt;greater &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;ability &lt;/ins&gt;to &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;collect &lt;/ins&gt;any &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;frogs that might &lt;/ins&gt;be &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;floating around in interplanetary space&lt;/ins&gt;. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;accurately &lt;/ins&gt;explain why, after evolving on Earth, no frogs have jumped to other celestial objects.&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>2601:1C0:8080:3C70:10F8:D748:A1E9:ECB3</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407309&amp;oldid=prev</id>
		<title>2601:1C0:8080:3C70:10F8:D748:A1E9:ECB3: /* Explanation */</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=407309&amp;oldid=prev"/>
				<updated>2026-02-27T01:52:30Z</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 01:52, 27 February 2026&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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 drawing to the right of the formula shows a planet with exactly the radius ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;. Thus the frog can jump really high compared to the planet's size (in this case about as high as the planet's radius), before it falls back down. This implies that the frog is jumping at somewhat less than the 4.5&amp;amp;#8239;m/s needed to escape.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth.&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;The title text points out that the ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; of the Earth is about 1.5 light days, which is about 7 times the distance to {{w|Pluto}} (compare to the 9&amp;amp;#8239;mm Schwarzschild radius). Since Earth's radius is much smaller than this, no frogs will be able to escape, so all frogs that stray into Earth's gravitational well would collect here on Earth. As far as we know, all the frogs in the Solar System are on Earth{{Citation needed}}, so the data apparently matches the theory. However, the reasoning is incorrect, as many other astronomical bodies in our solar system also have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than their physical radius&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;, and five of them (the Sun and the four giant planets) have ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; greater than Earth's&lt;/ins&gt;. If a frog were to be on any of those other bodies, it wouldn't be able to jump away to fall to Earth. A flawed argument neither supports nor refutes the conclusion, although it is true as far as we know that all frogs in the solar system do live on Earth&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;. Earth's ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt; exceeding its physical radius does factually explain why, after evolving on Earth, no frogs have jumped to other celestial objects&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;&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&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;If you were to take a frog off the earth and put it in a tiny frog space suit, which somehow did not unduly inhibit its movement, it could jump off any number of the smaller bodies in the solar system. However, few of these bodies are small/low-mass enough for a frog to escape them, ''and'' large enough and close enough for us to observe them and accurately estimate their escape velocities. (The diameter of asteroid {{w|4942 Munroe}} is known to be about 3.45&amp;amp;#8239;km, but its shape and mass are unknown. Its surface has an [https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2004942 exceptionally high albedo of 0.936], which suggests that the surface is mostly some kind of ice. If we assume that asteroid Munroe is spherical and entirely composed of water ice, with a density close to 1&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 2.16&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;10&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.041&amp;amp;#8239;m/s. If instead it's a solid sphere of meteoric iron/nickel with a density of about 8&amp;amp;#8239;g/cm&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, its mass is 1.72&amp;amp;#8239;×&amp;amp;#8239;10&amp;lt;sup&amp;gt;11&amp;lt;/sup&amp;gt;&amp;amp;#8239;kg, and its escape velocity is 0.115&amp;amp;#8239;m/s. In either case, Space Frog would have no trouble jumping away from Munroe.) Some examples:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>2601:1C0:8080:3C70:10F8:D748:A1E9:ECB3</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=404075&amp;oldid=prev</id>
		<title>82.132.238.142: /* Transcript */ Deredlinking, by using the site's proper cat-name (well, proper Americanized name, it's different from.the Anglicised version I'd use). Also, no idea what the broken file link is. Can't it be fixed/changed?</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=404075&amp;oldid=prev"/>
				<updated>2026-01-21T13:52:20Z</updated>
		
		<summary type="html">&lt;p&gt;‎&lt;span dir=&quot;auto&quot;&gt;&lt;span class=&quot;autocomment&quot;&gt;Transcript: &lt;/span&gt; Deredlinking, by using the site&amp;#039;s proper cat-name (well, proper Americanized name, it&amp;#039;s different from.the Anglicised version I&amp;#039;d use). Also, no idea what the broken file link is. Can&amp;#039;t it be fixed/changed?&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;
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				&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 13:52, 21 January 2026&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-l51&quot; &gt;Line 51:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 51:&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;[[Category:Animals]]&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;[[Category:Animals]]&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;[[Category:Geometry]]&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;[[Category:Geometry]]&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;[[Category:&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;Mathematics&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;[[Category:&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;Math&lt;/ins&gt;]]&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;[[Category:Pages with broken file links]]&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;[[Category:Pages with broken file links]] &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;&amp;lt;!-- where? What? --&amp;gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>82.132.238.142</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=404065&amp;oldid=prev</id>
		<title>112.206.106.74 at 03:01, 21 January 2026</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=404065&amp;oldid=prev"/>
				<updated>2026-01-21T03:01:21Z</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;
				&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 03:01, 21 January 2026&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-l50&quot; &gt;Line 50:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 50:&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;[[Category:Astronomy]]&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;[[Category:Astronomy]]&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;[[Category:Animals]]&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;[[Category:Animals]]&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 style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;[[Category:Geometry]]&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 style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;[[Category:Mathematics]]&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 style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;[[Category:Pages with broken file links]]&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>112.206.106.74</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=403877&amp;oldid=prev</id>
		<title>Utdtutyabthsc: /* Explanation */ This looks detailed enough to be complete.</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=403877&amp;oldid=prev"/>
				<updated>2026-01-19T07:07:02Z</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; This looks detailed enough to be complete.&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 07:07, 19 January 2026&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;/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;==Explanation==&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;==Explanation==&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;&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;{{incomplete|This page was created by an A frog stuck on mars. Don't remove this notice too soon.}}&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;&amp;#160;&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;The {{w|Schwarzschild radius}} is essentially the size of a {{w|black hole}} -- the maximum distance from the center where gravity is so strong that light can't escape. It is part of a solution to {{w|Einstein's field equations}}. It is usually calculated as&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 {{w|Schwarzschild radius}} is essentially the size of a {{w|black hole}} -- the maximum distance from the center where gravity is so strong that light can't escape. It is part of a solution to {{w|Einstein's field equations}}. It is usually calculated as&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;:''r''&amp;lt;sub&amp;gt;s&amp;lt;/sub&amp;gt; = (2*''G*M'') / ''c''&amp;lt;sup&amp;gt;2&amp;lt;/sup&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;:''r''&amp;lt;sub&amp;gt;s&amp;lt;/sub&amp;gt; = (2*''G*M'') / ''c''&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Utdtutyabthsc</name></author>	</entry>

	<entry>
		<id>https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=402698&amp;oldid=prev</id>
		<title>82.132.244.242: Undo revision 402697 by 180.181.250.224 (talk) 9mm radius means 18mm diameter hence &quot;a bit less than 2 cm&quot; is correct.</title>
		<link rel="alternate" type="text/html" href="https://www.explainxkcd.com/wiki/index.php?title=3181:_Jumping_Frog_Radius&amp;diff=402698&amp;oldid=prev"/>
				<updated>2025-12-31T01:51:01Z</updated>
		
		<summary type="html">&lt;p&gt;Undo revision 402697 by &lt;a href=&quot;/wiki/index.php/Special:Contributions/180.181.250.224&quot; title=&quot;Special:Contributions/180.181.250.224&quot;&gt;180.181.250.224&lt;/a&gt; (&lt;a href=&quot;/wiki/index.php?title=User_talk:180.181.250.224&amp;amp;action=edit&amp;amp;redlink=1&quot; class=&quot;new&quot; title=&quot;User talk:180.181.250.224 (page does not exist)&quot;&gt;talk&lt;/a&gt;) 9mm radius means 18mm diameter hence &amp;quot;a bit less than 2 cm&amp;quot; is correct.&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 01:51, 31 December 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-l14&quot; &gt;Line 14:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 14:&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;:''r''&amp;lt;sub&amp;gt;s&amp;lt;/sub&amp;gt; = (2*''G*M'') / ''c''&amp;lt;sup&amp;gt;2&amp;lt;/sup&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;:''r''&amp;lt;sub&amp;gt;s&amp;lt;/sub&amp;gt; = (2*''G*M'') / ''c''&amp;lt;sup&amp;gt;2&amp;lt;/sup&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;div&gt;where ''G'' is the {{w|gravitational constant}}, ''M'' is the mass of the object, and ''c'' is the {{w|speed of light}}. &amp;#160;&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;where ''G'' is the {{w|gravitational constant}}, ''M'' is the mass of the object, and ''c'' is the {{w|speed of light}}. &amp;#160;&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;If ''M'' were the mass of the {{w|Earth}}, it would give the Schwarzschild radius for the Earth, which is about 9 mm. (If all of Earth's mass were compressed into a sphere of a bit less than &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;1 &lt;/del&gt;cm in diameter, it would become a black hole.)&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;If ''M'' were the mass of the {{w|Earth}}, it would give the Schwarzschild radius for the Earth, which is about 9 mm. (If all of Earth's mass were compressed into a sphere of a bit less than &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;2&amp;amp;#8239;&lt;/ins&gt;cm in diameter, it would become a black hole.)&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 comic suggests a more useful radius: the ''Jumping Frog radius'' ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;, which is the size of a &amp;quot;planet&amp;quot; such that its gravity keeps a champion {{w|Frog jumping contest|jumping}} {{w|The Celebrated Jumping Frog of Calaveras County|frog}} from being able to achieve {{w|escape velocity}}. Thus [[Randall]] has instead of ''c'', the 299,792,458&amp;amp;#8239;m/s speed of light, used a much smaller value of 4.5&amp;amp;#8239;m/s, to represent the maximum speed of a jumping frog. It is possible that Randall got that value from [https://www.researchgate.net/publication/5661154_Explosive_Jumping_Extreme_Morphological_and_Physiological_Specializations_of_Australian_Rocket_Frogs_Litoria_nasuta this paper], which on page 179 puts an upper limit on the maximum velocity of adult Australian {{w|striped rocket frog}}s at 4.52&amp;amp;#8239;m/s. (The frog is shown making a &amp;quot;ribbit&amp;quot; sound, which is made by {{w|Pacific tree frog}}s and their relatives in North America and not by rocket frogs, but it's [https://www.imdb.com/list/ls052470723/ widely attributed to frogs all over the world].)&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 comic suggests a more useful radius: the ''Jumping Frog radius'' ''r''&amp;lt;sub&amp;gt;jf&amp;lt;/sub&amp;gt;, which is the size of a &amp;quot;planet&amp;quot; such that its gravity keeps a champion {{w|Frog jumping contest|jumping}} {{w|The Celebrated Jumping Frog of Calaveras County|frog}} from being able to achieve {{w|escape velocity}}. Thus [[Randall]] has instead of ''c'', the 299,792,458&amp;amp;#8239;m/s speed of light, used a much smaller value of 4.5&amp;amp;#8239;m/s, to represent the maximum speed of a jumping frog. It is possible that Randall got that value from [https://www.researchgate.net/publication/5661154_Explosive_Jumping_Extreme_Morphological_and_Physiological_Specializations_of_Australian_Rocket_Frogs_Litoria_nasuta this paper], which on page 179 puts an upper limit on the maximum velocity of adult Australian {{w|striped rocket frog}}s at 4.52&amp;amp;#8239;m/s. (The frog is shown making a &amp;quot;ribbit&amp;quot; sound, which is made by {{w|Pacific tree frog}}s and their relatives in North America and not by rocket frogs, but it's [https://www.imdb.com/list/ls052470723/ widely attributed to frogs all over the world].)&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>82.132.244.242</name></author>	</entry>

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