APOD 2.2

The APOD from December 8th shows an image of Saturn's moon Tethys taken from the Casini orbiter. The white color of the moon is described to have been formed by ice particles form Saturn's rings, which is interesting because I had always assumed that it was the moons that fed the rings via debris knocked loose from impacts. The ring in question is the E ring which is fed by ice particles from Enceladus, another moon of Saturn. Unlike other ice moons, Tethys is believed to be completely solid, rather than an ice surface over a liquid ocean.