Jupiter's satellite Europa
(Photo courtesy of NASA)
Europa, the smallest of Jupiter's 4 Galilean satellites, photographed by the Voyager 1 spacecraft on March 4, 1979, from a range of 2 million kilometres. The bright areas are thought to be ice deposits, while the dark areas maybe the rocky surface or areas with a more patchy distribution of ice. The most unusual features are the systems of long linear structures which criss- cross the surface. Some of these structures are over 1000 km long & about 2-3 km wide. They may be fractures or faults which have disrupted the surface.