Epimetheus

Without much fanfare from the popular press, the Cassini probe is quietly continuing its remarkable scientific mission. The latest photographic tour de force is this photo of the moon Epimetheus, described below:

Epimetheus is irregularly shaped and dotted with soft-edged craters. The many large, softened craters on Epimetheus indicate a surface that is several billion years old. The moon shares an orbit with another of Saturn's small moons, Janus. The two dance in a planetary tango as they move in almost identical orbits, exchanging orbits every four years, instead of colliding. Both play a role in creating intricate waves in Saturn¿s rings; both have densities significantly lower than that of solid ice, suggesting they may be "rubble piles" held together by gravity. At 116 kilometers (72 miles) across, Epimetheus is slightly smaller than Janus at 181 kilometers (113 miles) across. Spectra of Epimetheus from the Cassini visual infrared mapping spectrometer indicate that the moon is mostly water ice.

Much more information at the official Cassini site. Click on the image for a full-sized view...

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