The distinctive ejecta blanket that surrounds them is darker nearer the craters and brighter further away. The flow was probably icy surface material melted by the energy released during the impact that formed the crater. Geological mysteries on Ganymede T his image shows some unusual features on the surface of Jupiter's moon, Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. Situated in the transitional region between these two terrain types, the area shown here contains many complex tectonic structures, and small fractures can be seen crisscrossing the image.
North is to the top-left of the picture, and the sun illuminates the surface from the southeast.
The origin of these features is the subject of much debate among scientists analyzing the data. Scientists continue to study this data in order to understand the surface processes occuring on this complex satellite. Grooved Terrain in Nippur Sulcus on Ganymede C omplex sets of ridges and grooves are visible in this image of the Nippur Sulcus region on Jupiter's largest moon Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. The Nippur Sulcus region is an example of Bright Terrain on Ganymede which is typified by multiple sets of ridges and grooves.