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PHOTO CAPTION                                     P-47057
                                                  July 10, 1996
 
Ridges, grooves, craters and relatively smooth areas in the Uruk
Sulcus region of Jupiter's moon Ganymede are shown in this
high-resolution image captured by NASA's Galileo spacecraft
during its first flyby of Ganymede on June 27, 1996.  This image
was taken when Galileo was 7,448 kilometers (4.628 miles) away
from Ganymede; north is to the top of the picture, and sunlight
illuminates the surface from the lower left nearly overhead (77
degrees above the horizon).  The area shown, at latitude 10
degrees north, longitude 168 degrees west, is about 55 by 35
kilometers (34 by 25 miles); the smallest features that can be
discerned are 74 meters (243 feet).  The line-like features are
sunlit ridges, often arranged in parallel sets.  The patterns of
ridges and grooves indicate that extension (pulling apart) and
shear (horizontal sliding) have both shaped the icy landscape.
The Jet Propulsion Laboratory manages the Galileo mission for
NASA's Office of Space Science.