Hippocamp

Hippocamp is one of Neptune’s smallest and most interesting moons. It was officially announced as a moon in 2019 after scientists studied images taken by the Hubble Space Telescope. Because it is so tiny and faint, it was not seen when Voyager 2 passed Neptune in 1989. Hippocamp orbits very close to Neptune, and it takes only about one Earth day to go around the planet. Even though it is extremely small—only around 34 kilometers across—it has become an important part of understanding Neptune’s moon system.

Scientists believe Hippocamp may be connected to another moon called Proteus. Proteus is much larger, and long ago it was likely hit by a large object from space. When that collision happened, pieces of Proteus may have broken off and formed Hippocamp. This idea helps explain why Hippocamp orbits so close to Proteus and why it is so small. Studying Hippocamp gives scientists clues about how moons can form from debris and survive for billions of years.

The name “Hippocamp” comes from mythology, where a hippocamp is a creature with the upper body of a horse and the tail of a fish. Because Neptune is named after the Roman god of the sea, many of its moons are named after sea-related characters or creatures. Even though Hippocamp is tiny and hard to see, it plays a role in helping scientists understand Neptune’s history, the effects of collisions in space, and how small moons can evolve over time. It shows that even the smallest objects in our solar system can teach us something new.