Voyager 2 image of Neptune's largest moon, Triton. The large south polar cap which fills most of the image is thought to consist of a slowly- evaporating layer of nitrogen ice, deposited during the previous winter. North of the cap, is a region which has been dubbed the cantaloupe" terrain. Small dimples with upraised rims and shallow central depressions dot the area. Long fractures cross the region and extend into the polar cap. Towards the south this terrain has a light covering of frost. No large impact craters are visible, suggesting that the crust of Triton has been renewed relatively recently; that is within the past billion years."