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Explanation: 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...

Cassini flew just 25,620 miles (41,230 kilometers) from the pockmarked moon Jan. 30, on the spacecraft's seventh and final flyby of the moon. Due to a massive crater on one side, Mimas is known as the "Death Star" moon — but this time, that crater is out of view. (Another recent Cassini photo, from a November flyby, highlights the giant Herschel crater.) During the flyby, Cassini captured 10 images from about 28,000 miles (45,000 km) away that were combined into a mosaic. More than half the moon was lit only by reflected light from Saturn — one image has that...

Explanation: Whatever hit Mimas nearly destroyed it. What remains is one of the largest impact craters on one of Saturn's smallest moons. The crater, named Herschel after the 1789 discoverer of Mimas, Sir William Herschel, spans about 130 kilometers and is pictured above. 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 above image was taken during the 2010 February...