What are the Moons of Neptune?
Neptune, the eighth and last planet from the Sun since the demotion of Pluto in 2006, has 13 known moons. This is about half that of its sister planet Uranus, and a quarter that of Jupiter or Saturn. For its large mass, about 17 times that of Earth, Neptune has relatively few moons. In rough order of decreasing size, the moons are Triton, Proteus, Nereid, Larissa, Galatea, Despina, Thalassa, Naiad, Halimede, Neso, Sao, Laomedeia, and Psamathe. Triton was the first to be discovered, by William Lassell, who also discovered a moon of Saturn and two of Uranus, in 1854, only seventeen days after the discovery of Neptune itself. Only more than a hundred years later, in 1949, was another moon, Nereid, discovered. Nereid and Triton are named after lesser sea deities, a naming tradition that has persisted with the other moons. This naming scheme is inspired by the fact that Neptune, the Roman god of the sea. Up until 1989, only Triton and Nereid were known, but six were discovered that very yea
