One thing about our Solar System: It is absolutely loaded with water. Most of it is ice, and is found everywhere from comets to the rings of Saturn, the poles of Mars and the Moon, the asteroid belt, the Kuiper belt and the Oort cloud. But in recent years, we’re finding more and more water in liquid form. The latest evidence suggests that Neptune’s moon Triton (like many other moons around Jupiter and Saturn) may be hot enough at its core to melt the deeper layers of the crust into a vast subsurface ocean, according to a paper published in last month’s Icarus by Saswata Hier-Majumder .
But this is no ordinary water: it is very, very cold, at a temperature of almost one hundred degrees below zero (one-fifty, if you use Fahrenheit). Two things act to keep it liquid: It is under very high pressure, which inhibits the formation of ice, and it has a very high concentration of ammonia which has good antifreeze properties. So future travellers won’t quite be able to tap it for a refreshing drink, but it’s still water and it’s still liquid, which means we can add yet another candidate location to find extra-terrestrial life.
Triton is the seventh largest moon in the Solar System, and the largest orbiting Neptune. It has a diameter of about 2700km and is the only moon to orbit its planet backwards. Most of what we know about Triton comes from data collected by Voyager 2, when that spacecraft passed by in 1989.