This image of Ganymede was taken by Voyager 1, 246,000
kilometers (158,000 miles) from the planet. The center of the
picture is at 19 south latitude and 356 longitude, and the height
of the frame represents a distance of about 1000 kilometers
(600 miles) on the surface. The smallest features seen on this
picture are about 2.5 kilometers (1.5 miles) across. The surface
displays numerous impact craters many of which have extensive
bright ray systems. The craters lacking ray systems are probably
older than those showing rays. Bright bands traverse the surface
in various directions and these bright bands contain an intricate
system of alternating linear bright and dark lines which may
represent deformation of the crusted ice layer. These lineations
are particularly evident near the top of the picture. A bright band
trending in a north-south direction in the lower left-hand portion
of the picture is offset along a bright line. This offset is probably
due to faulting. Two light circular areas in the right upper center
of the picture may be the scars of ancient impact craters which
have had their topographic expansion erased by flowage of the
crystal icy material.

This image is in the public domain and credit should be given to
Calvin J. Hamilton.