Triton and Proteus are moons of the planet Neptune. With a diameter of 1,700 miles, Triton is the largest moon. William Lassell discovered this moon in 1846. The Voyager 2 spacecraft discovered Proteus in 1989. Proteus is Neptune's second largest moon.Continue Reading
Neptune has other moons, such as Nereid, Galatea, Larissa and Naiad. Discovered in 1949, Nereid is Neptune's third largest moon. As of 2014, Neptune has 14 known moons.
In the solar system, Neptune is the farthest planet from the sun. It also is a gas giant that has a surface temperature of -346 degrees Fahrenheit. Its atmosphere contains helium hydrogen and small quantities of methane. Neptune���s rotation about the sun takes approximately 164.8 Earth years.Learn more about Planets