Geysers on Neptune's moon Triton, illustration. At top, the orbit of Neptune around the Sun and the orbit of Triton around Neptune (red arrows) is shown for Neptune's southern summer (left) and Neptune's northern summer (right). At left, Triton has one hemisphere in permanent sunlight. At right, Triton has the opposite hemisphere in permanent sunlight. The effects of this permanent sunlight (yellow arrows, centre) is to melt ice below the surface. At bottom, cracks open in the surface, geysers boil into space, and prevailing winds (arrows) blow the geysers in the same direction. Particles in the geysers drift back to the surface, seen from space as patterns of dark streaks.