This composite image of Enceladus, one of Saturn's many moons, comes from an October visit by the Cassini spacecraft. The incredible detail of the photograph shows the fractures that indicate significant geological activity on the icy moon. The deep chasm visible in the upper half of the image is Labtayt Sulci, a furrow some 0.6 mile (one kilometer) deep. (Enceladus itself is only about 300 miles, or roughly 500 kilometers, in diameter.) The 28 images that constitute this mosaic were taken as Cassini drew away from Enceladus after a flyby that brought the spacecraft to within 15.6 miles (25 kilometers) of the moon's surface. See more images from Enceladus in our November slide show.