As someone new to the world of astronomy, you might think that the Earth is the only planet with a moon or assume that all planets have one moon. Missions and trips through space revealed that some planets have more than one moon, including Neptune that has 14 moons. One thing to keep in mind is that NASA and astronomers refer to smaller objects that orbit a planet has a satellite, which is a type of moon. We’ll take a detailed look at this planet and the moons of Neptune in the following article.
Neptune Has Rings and Moons
Neptune is one of the only planets in our solar system with rings. It has five rings or ring arcs that were first identified in 1984. The planet also has 14 moons, including both regular and irregular moons. Triton is an example of an irregular moon that follows a different path than the planet does. This also ranks as the largest moon of Neptune. All 14 of the moons of Neptune use the names of Greek goddesses and gods. Most of the planet’s moons formed from debris and gases in space.
Triton
The largest of all of Neptune’s moons is Triton. William Lassell was an astronomer working in England who first identified this planet in 1846. It has a retrograde orbit, which means that instead of rotating in the same direction as the planet, it moves in the opposite direction. Lassell was the first person to claim that Neptune also had rings. Camille Flammarion suggested the name Triton as easily as 1880, but it took many years before others used this name. Early astronomers thought that Triton was the only moon of Neptune, which is why they often called it the satellite of Neptune.
Voyager 2
It took more than a century before astronomers discovered that Neptune had more than one moon. NASA launched Voyager 2 in 1977. This craft traveled through space and sent back information to Earth. In 1989, Voyager 2 charted a path past Neptune and found that it had five smaller moons. Naiad is one of the largest and also called Neptune III. Close by is Thalassa, which astronomers named after a Greek goddess. The other moons identified by Voyager 2 include Proteus, Galatea and Despina. Each of those moons has an official name that relates to a Greek god or goddess.
Land Surveys
Though you might think that NASA only identified the moons of Neptune while traveling through space, some work on the land revealed the presence of other satellites. Five of the planet’s moons were found in 2001 through surveys on the ground that used telescopes. Two different teams working in the following years tracked those moons again and gave them official names. Neso, Halimede, Psmathe, Laomedia and Sao were the names given to those later moons. One unique fact about Neptune’s moons is that none had official names until the 20th century. This was due in part to the belief that Neptune had just one.
Does Neptune Have a Lost Moon?
Workers conducting a land survey in 2002 spotted what they thought was the 14th moon of Neptune. They found that is was more than 25 million miles away from the planet and that it had a diameter of 33 kilometers. When the team went back, they couldn’t find any proof that the moon existed. Some now believe that this was a centaur, which is a mini solar system that orbits close to a planet. Others think that it was a moon because of how close it was to Neptune and the way it followed the path of the planet.
Hippocamp
The 14th official moon of Neptune is Hippocamp, which was discovered in 2013. Michael Showalter was looking at images taken by the Hubble Space Telescope to examine the rings around the planet. He found a small dot just outside of the rings that he believed indicated the presence of a new moon. Astronomers have two theories as to how the moon formed. While one claims that it formed from debris left behind after the formation of Triton, others think that it formed from debris after a comet struck another moon. Hippocamp is so dim that previous photos and missions did not notice it.