Titan (moon)
Future conditions

Conditions on Titan could become far more habitable in the far future. Five billion years from now, as the Sun becomes a sub- red giant, its surface temperature could rise enough for Titan to support liquid water on its surface, making it habitable. As the Sun's ultraviolet output decreases, the haze in Titan's upper atmosphere will be depleted, lessening the anti-greenhouse effect on the surface and enabling the greenhouse created by atmospheric methane to play a far greater role. These conditions together could create a habitable environment, and could persist for several hundred million years. This is proposed to have been sufficient time for simple life to spawn on Earth, though the higher viscosity of ammonia-water solutions coupled with low temperatures would cause chemical reactions to proceed more slowly on Titan.
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