Ganymede (natural colors and HR)

Caption NASA originale:"This color picture was acquired by Voyager 1 during its approach to Ganymede. At ranges between about 230 to 250.000 Km. The images show detail on the surface with a resolution of 4,5 Km/px. This picture is relevant to a region in the Northern Hemisphere, near the terminator. It shows a variety of impact structures, including both razed and unrazed craters, and the odd, groove-like structures discovered by Voyager in the lighter regions. 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".