The moon Iapetus, like the 'force' in Star Wars, has both a light side and a dark side. Scientists think that Iapetus' dark/light asymmetry was actually created by material migrating away from the dark side.
A large crater can be seen in the southern hemisphere of Saturn's two-tone moon Iapetus. Lit terrain seen here is on the trailing hemisphere while the leading hemisphere is extremely dark and whose trailing hemisphere is as white as snow.
The two-toned surface of Saturn's moon Iapetus is demonstrated in the dark region of the moon visible on the top left and the bright crater in the lower right of this portrait captured by NASA's Cassini spacecraft.
The oblate shape of the moon Iapetus is particularly noticeable in this portrait; the two-toned surface of the moon Iapetus also stands out against the darkness of space in this image taken by NASA's Cassini spacecraft.
This false-color view taken by NASA's Cassini spacecraft is one of a panel of three images of Saturn's moon Iapetus showing the boundary of the global 'color dichotomy' on the hemisphere of this moon facing away from Saturn.
This stereo view of Iapetus was created by combining two NASA Cassini images, which were taken one day apart. The view serves mainly to show the spherical shape of Iapetus and some of the moons topography. 3-D glasses are necessary to view this image.