As it rockets toward its July 1 entry into Saturn’s orbit, NASA’s Cassini-Huygens spacecraft is capturing some stunning views of one of the gas giant’s moons, Phoebe.
Images like this one, showing bright wispy streaks thought to be ice revealed by slumping crater walls, are leading to the view that Phoebe is an ice-rich body covered with a thin layer of dark material. Obvious down slope motion of material along the walls of the major craters in this image is the cause for the bright streaks, which are over-exposed here. Significant slumping has occurred along the crater wall at top left.
The slumping of material might have been caused by a small projectile punching into the steep slope of the wall of a pre-existing larger crater. Another possibility is that the material collapsed when triggered by another impact elsewhere on Phoebe. Note that the bright, exposed areas of ice are not very uniform along the wall. Small craters are exposing bright material on the floor of the larger crater.Image Credit: NASA/JPL/Space Science Institute+ View Full Caption+ View High Resolution Image+ View Cassini-Huygens Image Archive