I
In Greek mythology , a merman and a demigod of the sea.
He was the son of Poseidon and Amphitrite. According to Hesiod , Triton lived in a golden palace in the depths of the sea. He was represented as human down to the waist, which tapered into a fish tail, and he had a spiral conch shell that he blew to calm or raise the waves. Some traditions held that there were many Tritons.
II
Largest of Neptune 's known moons.
Its diameter is about 1,680 mi (2,700 km), somewhat less than that of Earth's Moon. Triton moves in a retrograde orbit, opposite the direction of Neptune's rotation, with a period of 5.9 Earth days, while keeping the same face toward Neptune. It has a very thin atmosphere of nitrogen and methane and a surface temperature of -400 kF (-240 kC). Its surface is covered with enormous expanses of ice sculpted with fissures, puckers, and ridge-crossed depressions and pitted by what appear to be a few meteorite craters. Plumes of gas observed by the Voyager 2 spacecraft may be gas venting through fissures when the surface is warmed by sunlight.