This Voyager 2 photograph of the Uranian Moon Ariel is the best quality to date.

This Voyager 2 photograph of the Uranian Moon Ariel, is the best quality to date. This view of Ariel's southern hemisphere is a composite of photographs taken through green, blue, and violet filters from the narrow angle camera. Most of the visible surface consists of relatively intensely cratered terrain transected by fault scarps and fault bounded valleys (graben). Some of the largest valleys, which can be seen near the terminator (at right), are partly filled with younger deposits that are less heavily cratered. Bright spots near the limb and toward are chiefly the rims of small craters. Most of the brightly rimmed craters are too small to be resolved here, although one about 30 km. (20 mi.) in diameter can be easily distiguished near the center. These bright-rim craters, thogh the youngest features on Ariel, probably have formed over a long span of geological tome. Although Ariel has a diameter of abou 1,200 km. ( 750 mi. ), it clearly experienced a great deal of geological activity in the past.