xkcd #3181: Jumping Frog Radius
Title text:
Earth's r_jf is approximately 1.5 light-days, leading to general relativity's successful prediction that all the frogs in the Solar System should be found collected on the surface of the Earth.
Transcript:
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Source: https://xkcd.com/3181/
This, I think, is related to where I draw the line between a 'moon' and a 'sattelite.' If an average human can hit escape velocity under muscle power, it's a satellite. If you can strand someone there, it's a moon.