Voyager 2 took this image of Neptune in 1989, two hours before it made its closest approach to the planet. Neptune's surface is not like Earth's. While these thick clouds cover the surface, the interior of the planet is made up of heavy, compressed gases. Its core is composed of rock and ice. What does the future hold for Neptune and its moons? In 2005, a team of researchers backed by NASA came up with a plan to land a team of explorers on Triton.