Cassini At Rhea

The Cassini spacecraft recently made a close flyby of Saturn's second largest moon, Rhea. Rhea, which is roughly 950 miles in diameter, has not yet generated the interest that Titan-- about three times bigger than Rhea-- or Enceladus-- three times smaller-- have.

The images returned by Cassini won't necessarily change that. At first look, they show a surface hammered by impacts. It is dominated by craters. There is also a scarp or two. While scarps might possibly suggest internal activity, the heavily cratered surface so far revealed argues that nothing except pounding from outside has happened on Rhea in a while. Of course, that's subject to change. Coming images might reveal a different character, and studying the ages of the craters could also reveal a different history.