Ganymede (natural colors and HR)

Caption NASA originale:"This color picture as acquired by Voyager 1 during its approach to Ganymede, at ranges between about 230 to 250.000 Km. The image shows detail on the surface with a resolution of 4,5 Km/px.
This picture shows the two distinctive types of terrain found by Voyager: the darker ungrooved regions and the lighter areas which show the grooves or fractures in abundance. The most striking features are the bright ray craters which have a distinctly "bluer" color appearing white against the redder background. Ganymede's surface is known to contain large amounts of surface ice and it appears that these relatively young craters have spread bright fresh ice materials over the surface. Likewise, the lighter color and reflectivity of the grooved areas suggests that here too, there is cleaner ice. We see ray craters with all sizes of ray patterns, ranging from extensive systems of the crater in the northern part of this picture, which has rays at least 300-500 kilometers long, down to craters which have only faint remnants of bright ejecta patterns".