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Water Worlds: Triton

September 26, 2012

There’s no other world quite like Triton, the largest moon of the planet Neptune.

For one thing, it orbits in the opposite direction from Neptune’s rotation. That means it was captured by Neptune instead of forming with the giant planet. It also means that Triton will eventually be pulverized as it spirals inward.

Triton’s surface is different, too. Much of it looks like the skin of a cantaloupe. And some areas are marked by long dark streaks — the plumes of large, icy geysers.

But in one way, Triton may be similar to some of the solar system’s other large moons: It may have an ocean of liquid water far below the surface.

Triton is one of the coldest worlds in the solar system. Its surface is made of water that’s frozen as hard as granite.

But recent research suggests that its interior could have been heated enough in the past to melt some of the ice below the surface. Some of the heat came from radioactive elements in Triton’s core. But Triton originally followed a much more elongated orbit than it does today. As its distance from Neptune changed, Neptune’s gravity continually stretched and squeezed Triton, heating its interior.

Triton’s orbit is more circular today, but it may still generate enough heat to maintain an ocean. The water may be mixed with ammonia, though. That would keep the ocean liquid even at temperatures that are cold enough to freeze water alone.

We’ll talk about another water world tomorrow.


Script by Damond Benningfield, Copyright 2012

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