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Life on Triton?
Triton is a little bit like Jupiter's moon Europa, and a little bit like Saturn's moon Titan. There is a very thin atmosphere which is a bit like Titan's. It is very cold, about -300 degrees. Like the Earth, there is Nitrogen and other complex molecules. Nitrogen is one of the waste products left behind by life forms. Except for the cold, these signs would be favorable for some sort of life.Like other icy moons, Triton is small, with direct exposure to space and the charged particle environment of Neptune's magnetosphere. These signs are less favorable for life.
The interior of Triton may have been warm enough at one time to contain a liquid layer just under the surface. On Earth, we know that there are some creatures which can survive in an environment of very cold water, such as under the ice of the north pole.
Overall, the environment sounds unfriendly to life as we know it on earth, because of the radiation and the cold. However, if the interior is warm enough, and if the conditions are just right, there may be living creatures on Triton under the icy surface.