A portion of a chain of impact craters on Jupiter's moon Callisto is seen
in this image taken by the Galileo spacecraft on November 4, 1996. This
crater chain on Callisto is believed to result from the impact of a split
object, similar to the fragments of Comet Shoemaker-Levy 9 which smashed
into Jupiter's atmosphere in July of 1994. This high-resolution view,
taken by Galileo's solid state imaging television camera during its third
orbit around Jupiter, is of Callisto's northern hemisphere at 35 degrees
north, 46 degrees west, and covers an area of about eight miles (13
kilometers) across. The smallest visible crater is about 140 yards (130
meters) across. The image was taken at a range of 974 miles (1,567
kilometers).
On a global scale, Callisto is heavily cratered, indicating the great age
of its surface. At the scale of this image, it was anticipated that the
surface would be heavily cratered as well; however, there is a surprising
lack of small craters, suggesting that one or more processes have
obliterated these and other small-scale features. For example, downslope
movement of ice-rich debris could bury small craters. The bright slopes
visible in this picture represent places where downslope movement has
taken place, exposing fresh ice surfaces.
The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's
Office of Space Science, Washington, D.C.
This image and other images and data received from Galileo are posted on
the Galileo mission home page on the World Wide Web at
http://galileo.jpl.nasa.gov/. Background information and educational
context for the images can be found at http://www2.jpl.nasa.gov/galileo/sepo/.