One crater on Mimas is huge.  The impact that caused it probably came close to destroying Mimas.  The crater is named Herschel, after the famous 18th-century astronomer.  This giant crater is more than 80 miles (130 km) across.  That's more than a third of Mimas's total diameter!  There is a peak at the center that's 2.5 miles (4 km) high.  Its summit is higher than Mount Everest, Earth's tallest mountain.  Scientists do not understand exactly how Mimas was able to survive such a large impact.

    It is possible that other moons of Saturn were also struck by giant meteoroids or asteroids.  If they broke up, the pieces probably became part of the ring system.