My favorite citizen of the solar system, Saturn's moon Enceledus (the moons that switch orbits every four years are a close second and third*).
Three cool things about this picture.
One: that tiny flare of light coming from the bottom of the moon is caused by ice geysers, spewing ice hundreds of miles out into space. Carbon particles have been found in the ice. Water, carbon, and a heat source that causes the geysers. Sounds like Arthur C. Clarke's monolith is at work deep under the ice. It's full of staaaars....
Two: that faint line behind Enceledus is Saturn's E ring, composed almost entirely of ice particles form those crazy geysers, settling into orbit.
Three: look at the pattern of light and shadow on Enceledus. The bright crescent of light on the left, the dark bit, and then another bright section. There are two light sources! The bright crescent on the left is caused by sunlight. The light on the right is Saturnlight, the glow from the planet 150,000 miles away.
Thanks to Cassini, NASA, and Bad Astronomy for the pix and the info.
*the mysterious clump of particles orbiting Saturn that may or may not be a black hole is a distant fourth.
