Neptune and its moon, Triton

Blue Neptune is one of the solar system’s gas giants. Unlike Earth, gas giants are mostly hydrogen, helium, and methane gases. The methane gas on Neptune gives the planet its blue color because the gas absorbs red light and reflects the blue back into space. Although not seen in the image the planet has a set of very faint rings.

The Great Dark Spot, the dark oval on the planet, was a storm like the Great Red Spot on Jupiter. The storm has disappeared since this image was taken by Voyager 2 according to Hubble Space Telescope data but another spot was found in a different place. The atmosphere shows lots of activity including the white clouds of methane ice crystals seen in the image at left.

The unusual texture of one of Neptune’s moons, Triton, reminds some people of a cantaloupe. It is the largest moon to orbit retrograde (backwards) around a planet.

Neptune Moon Count Hits 13
Recently more moonlets have been found orbiting the planet, bringing its total to 13. Observers spotted them using large telescopes in Chile and Hawaii. They are the first Neptunian moons discovered since 1989 when Voyager 2 passed by. Their orbits indicate they may be from a collision between another moon and a large object.