Although made mostly of ice and rock, Saturn’s moon Dione (pronounced DEE-oh-nee) does have some color to it — although mostly chilly hues of steel blue, as seen in this color-composite made from raw images acquired by Cassini on July 23.
700 miles (1120 km) wide, Dione is covered pole-to-pole in craters and crisscrossed by long, bright regions of “wispy line” terrain — the reflective faces of sheer cliffs and scarps that are too steep for darker material (from Saturn’s E ring) to rest upon.
Dione’s heavily cratered areas are most common on the trailing hemisphere. Logically, a moon’s leading hemisphere should be the more heavily cratered, so it has been theorized that a more recent impact spun Dione around.
See more images of Dione’s surface here, taken during a very close pass on Sept. 4, 2010.
Image credit: NASA/JPL/Space Science Institute. Composite by Jason Major.