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Galileo's Legacy at Jupiter

artist's concept of Galileo at Jupiter
Ganymede - Ancient Impact Craters in Galileo Regio

The ancient impact craters shown in this image of Jupiter's moon Ganymede are in an area called Galileo Regio. It was taken from NASA's Galileo spacecraft and the craters testify to the great age of the terrain, dating back several billion years. The dark and bright lines running from lower right to upper left and from top to bottom are deep furrows in the ancient crust of dirty water ice. The origin of the dark material is unknown, but it may be accumulated dark fragments from many meteorites that hit Ganymede. The area shown is about 30 kilometers (19 miles) across. The image was taken June 27, 1996, at a range of 7,563 kilometers (4,700 miles). picture of this asteroid would appear mostly gray.