Triton is a world of extremes. It’s by far the largest moon of Neptune, with a radius of 1,350 kilometers, or just 22% smaller than Earth’s moon.

Triton was discovered in 1846 by the British astronomer William Lassell, but much about Neptune’s largest moon still remains a mystery.

To begin, Triton is considered to be one of the coldest places in our entire Solar System. The moon’s surface temperature is about -235°C on average, while Pluto averages about -229°C.

Neptune’s moon Triton was the last stop on Voyager 2’s tour of the outer planets. It is one of the coldest objects in the solar system and a big brother of Pluto, which NASA will visit next year.

There are many good arguments for why we should revisit Neptune's moon, three decades after Voyager 2 flew past. Triton has many peculiarities, including the fact it did not form around Neptune.