The heavily creased and cratered face of 700-mile-wide Dione is partially lit by the Sun in this image from Cassini, taken on March 4. Some of the moon’s characteristic “wispy lines” can be seen along its sunlit limb…these are the bright, exposed walls of icy canyons caused by ancient tectonic activity. The darker surface material that covers the rest of the moon can’t stick to these sheer cliffs, some many hundreds of feet high, and as a result they remain highly reflective to sunlight.

Image: NASA/JPL/SSI