Hippocamp, a moon of Neptune
65,430 miles
21 miles
Hippocamp is a moon of Neptune. It is one of Neptune's inner moons and is the sixth moon from the planet. Hippocamp has a diameter of approximately 34 kilometres (20 miles) and is the smallest moon of Neptune. It orbits Neptune at a distance of about 105,000 kilometres (65,000 miles). A length of an orbit takes 23 hours.
Hippocamp was discovered on 1st July 2013 by American astronomer Mark Showalter and is the most recently discovered moon of Neptune. He discovered it by looking through hundreds of photos of Neptune and its moons as taken by the Hubble Space Telescope between 2004 or 2009. It was observed again by the Hubble Space Telescope in 2016 and received its name in February 2019. It is the only one of Neptune's inner moons to have been discovered in the 21st Century.
Hippocamp orbits closely to Proteus, a much larger moon of Neptune, and it is possible that it was originally a part of Proteus that broke off when something crashed into Proteus.
Hippocamp is classed as a regular prograde moon. Regular moons are moons that formed out of materials spinning around a planet. Irregular moons are ones that were captured by a planet. A prograde moon is one which orbits in the same direction of the rotation of its host planet.
In Greek mythology, a hippocamp or hippocampus is horse with a fish's tail. It's kind of a seahorse, but a big one. Not one of those little ones you see in aquariums! The name was suggested by the discover of the moon, Mark Showalter, a keen scuba diver who likes seahorses.
Human beings have a hippocampus in their brain. This doesn't mean they have a seahorse or even a moon in their heads! The hippocampus is the part of the brain that helps people to learn and remember things and recall those memories. It gets its name because it looks a little like a seahorse. There are actually two of them in a human brain. Fascinating, eh? Nothing at all to do with space though!
Before it received its official name, Hippocamp was identified as S/2004 N1 or Neptune XIV.
