Neptune is the eighth planet from the sun and appears bright blue in color. It was discovered by German astronomer Johann Galle in 1846 and is named after the Roman god of the sea, Neptune. It is a sister planet to Uranus; both are ice giants that cannot support life.
Neptune has six rings named after scientists who played a role in Neptune's discovery. Each of Neptune's 13 moons is named after sea nymphs or gods from Greek mythology. The biggest moon is called Triton, which is actually larger than Pluto, sports active ice volcanoes, and revolves around Neptune in an unusual east-to-west direction. Neptune's atmosphere is comprised of methane, hydrogen and helium over a solid core made of ice and rock.
Neptune is 57 times larger than Earth with a 16-hour day and a year that lasts 165 Earth-years. Voyager 2 is the only spacecraft travel to Neptune. Compared to Earth, which is approximately 92 million miles from the sun, Neptune is located far out in the solar system, as the planet is 2.8 billion miles from the sun. In astronomical terms, that is 30.07 Astronomical Units, which is just over 30 times the distance from the sun to Earth.