Saturn's Moon Iapetus Has A 'Belt'

Believe writes "In another unexpected find by Cassini-Huygens, Saturn's moon Iapetus shows a bulging waistline. According to the story, the dark side of the moon is almost perfectly bisected by a tall, narrow ridge that runs for 1300 km (808 mi) and rises up to 20 km (12 mi) high. This height is amazing in such a small moon; it rivals Olympus Mons on Mars which is a body 5 times its size."

Comments

Why surprising?

[Velox_SwiftFox]

Why is it surprising that tall mountain ridges are found on small (relative to planets) moons, where there may be little weather and low gravity to cause their erosion?

Re:Why surprising?

[rhennigan]

I'm willing to bet there used to be a ring around the moon, that eventually fell out of orbit, piling up in a neat row around the equator. Then again, IANAKP (Knowledgable Person), so feel free to suggest why this might not be possible.

Sensible non-death-star explanation

[adeyadey]

Many of the smaller moons/asteroids are barely spherical, and having been hit so often, barely held together by gravity. given the size of the impact crater, it is possible this moon was nearly torn apart by that impact, and the belt is a relic of that event.

Some of the smaller moons & asteroids out there are more like piles of rubble held together by gravity than solid bodies - thus the headaches in what to do if one were ever found to be on collision course with earth, since an attempt to move it of course would merely fragment the body..