Does Triton Have a Subsurface Ocean?
Captured from the Kuiper Belt
Triton has a unique property among large solar system moons; it has a retrograde orbit. Planets form from a circumstellar disc of dust and gas that surrounds a young star. This disc circles the star in one direction, and thus the planets and their moons must also orbit in this same direction. These orbits are known as prograde, and a rogue object that orbits backwards is said to be in a retrograde orbit. The retrograde orbit of Triton means that it most likely did not form around Neptune.