Wikijunior:Solar System/Neptune/Proteus

Proteus from Voyager 2 spacecraft

Proteus is a moon of the planet Neptune. It is sometimes called Neptune VIII. We still do not know a lot about this moon, as only a few pictures have been taken when the Voyager 2 flew by in 1989.

How big is it?


This moon is uneven in shape and has an average size of just over 400 km across. This moon is nearly as a big as a satellite can be without it being pulled into a sphere by its own gravity. Even though it is a small moon, it is the second largest moon of Neptune after Triton.

What is its surface like?


The surface of this moon is covered in craters and some grooves. It is also a very dark moon, with a ground that is as dark as soot. It is one of the darkest objects in the Solar System.

How long is Proteus's revolution?


It takes 1 day, 2 hours, and 56 minutes for this moon to orbit the planet Neptune.

Who is it named after?


This moon is named for a sea god from ancient Greek mythology. In some tales he was the first son of Poseidon, the ancient Greek god of the sea. The Romans later called him Neptune, so Proteus was the first son of Neptune.

In Greek mythology, Proteus was able to foretell the future. He was also able to change his shape, and he used this ability to avoid being asked about what is to come.

How was it discovered?


Proteus was discovered in 1989 when the Voyager 2 spacecraft flew by Neptune.