Neptune

'''Neptune is the eight planet from our Sun. Neptune's''' atmosphere is made up of hydrogen, helium and methane. The methane in Neptune's upper atmosphere absorbs the red light from the sun but reflects the blue light from the Sun back into space. This is why Neptune appears blue. Neptune, like the other gas giants in our solar system, doesn't have much of a solid surface to live on. But the planet's largest moon, Triton, could make an interesting place to set up a space colony. So far, only a single spacecraft has ever visited Triton. Neptune was the first planet to be discovered by using mathematics. After the discovery of Uranus in 1781, astronomers noticed that the planet was being pulled slightly out of its normal orbit. ... They figured out not only where the planet was, but also how much mass it had. Neptune was the first planet to be discovered by using mathematics. After the discovery of Uranus in 1781, astronomers noticed that the planet was being pulled slightly out of its normal orbit. ... They figured out not only where the planet was, but also how much mass it had.