This photograph of Ganymede, the largest satellite of Jupiter, is shown at approximately the same distance as that photographed at close range by Voyager 1 in March. This picture, taken by Voyager 2, illustrates well the light, bluish regions near the north and south poles. It is known that there is exposed water ice on the surface of Ganymede, and pehaps these polar caps are composed of a light covering of water ice or frost. Voyager 2 will pass within 63,000 kilometers (39,000 miles) of Ganymede.