Astronomy Picture of the Day: Mimas
Saturn’s smallest spherical moon has the largest impact crater.
Whatever hit Mimas nearly destroyed it. What remains is one of the largest impact craters on one of Saturn‘s smallest round moons. Analysis indicates that a slightly larger impact would have destroyed Mimas entirely.
The huge crater, named Herschel after the 1789 discoverer of Mimas, Sir William Herschel, spans about 130 kilometers and is featured here. Mimas‘ low mass produces a surface gravity just strong enough to create a spherical body but weak enough to allow such relatively large surface features.
Mimas is made of mostly water ice with a smattering of rock – so it is accurately described as a big dirty snowball. The featured image was taken during the closest-ever flyby of the robot spacecraft Cassini past Mimas in 2010 while in orbit around Saturn.
See more here: nasa.gov
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Joseph Olson
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Hellas Planitia crater on Mars is 2300 km diameter with uniform concave depression 9 km deep indicating impact with a 294,000 diameter object, likely a brown dwarf and the Sun’s lost twin (Planet X)
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Zoe Phin
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And more …
http://phzoe.com/2020/04/21/the-strange-case-of-mimas/
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Joseph Olson
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some kids insist on coloring outside the lines….(congratulations! )
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Robert Beatty
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Joseph and Zoe,
In my book, https://bosmin.com/PSL/PlanetsSatellitesLandforms.pdf page 57, suggests Mimas is probably the result of early eye spot activity with the large impact craters resulting from associated launch trauma. This also fits in with Zoe’s reference to residual internal nuclear heating properties, as well as the posigrade rotation sequence for this satellite. The smaller impact craters dotting the surface of Mimas seem to be associated with kinetic pipe launches caused during the ongoing generation of Saturn’s ring structures.
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