This was
your sky.

The Strange Trailing Side of Saturn's Iapetus

Saturn's moon Iapetus is a strange world, with vast sections as dark as coal and others as bright as ice. The composition of the dark material is unknown, though infrared spectra suggest it contains a dark form of carbon. Iapetus also has an unusual equatorial ridge, giving it a walnut-like appearance. The Cassini spacecraft made a close flyby, coming within 2,000 kilometers, to help us better understand this mysterious moon.