How Many Moons Does Neptune Have?
Written by Fraser Cain
Neptune's largest Moon, Triton. Image credit: NASA/JPL
Did you want to know how many moons Neptune has? At the current count, Neptune has 13 moons.
Neptune's largest moon is Triton, which is actually one of the largest moons in the Solar System. Triton was first discovered by William Lassell just 17 days after Neptune itself was discovered.
It took another 100 years for Neptune's second moon, Nereid, to be discovered. Nereid was discovered by Gerard P. Kuiper, who the Kuiper Belt is named after.
And that's all the moons that astronomers thought Neptune had until 1981 when its third moon, Larissa, was discovered.
Astronomers lost track of Larissa until NASA's Voyager 2 spacecraft flew past Neptune in 1989. Voyager 2 found Larissa again, and discovered 5 additional inner moons: Naiad, Thalassa, Despina, Galatea and Proteus. After Voyager 2's flyby was complete, the total for Neptune's moons rose to 8.
And then in 2002 and 2003, astronomers uncovered 5 additional moons circling Neptune using Earth observatories. The newly discovered moons were named Halimede, Sao, Psamathe, Laomedeia, and Neso.
And that's how we reached the current total of 13 moons for Neptune.
Of course, if you ask the question again in a few years, it might be higher, since astronomers are working to uncover new moons around the planets all the time.
We have written many articles about Neptune's moons for Universe Today. Here's an article announcing three of the new moons discovered for Neptune, and here's an article about NASA's New Horizons spacecraft spotting Neptune's moon Triton.
Here's NASA's resource on Neptune's moons, and here's NASA's Solar System Exploration Guide on Neptune's moons.
We've done a whole episode of Astronomy Cast all about Neptune. Check it out.
Filed under: Astronomy
