Formation and evolution of the Solar System the Sun's increased radiation output, will cause its circumstellar habitable zone will move outwards, making the Earth's surface too hot for liquid water to exist there naturally. At this point, all life will be reduced to single celled organisms. Evaporation of water, a potent greenhouse gas, from the oceans' surface could accelerate temperature increase, potentially ending all life on Earth even sooner. During this time, it is possible that as Mars's surface temperature gradually rises, carbon dioxide and water currently frozen under the surface regolith will release into the atmosphere, creating a greenhouse effect that will heat the planet until
Extraterrestrial liquid water combined with evidence of ongoing cryovalcanic activity. Scientists' consensus is that a layer of liquid water exists beneath Europa's surface, and that heat energy from tidal flexing allows the subsurface ocean to remain liquid. The first hints of a subsurface ocean came from theoretical considerations of tidal heating (a consequence of Europa's slightly eccentric orbit and orbital resonance with the other Galilean moons). Scientists used gravitational measurements from the Cassini spacecraft to confirm a water ocean under the crust of Enceladus. Such tidal models have been used as theories for water layers in other Solar System moons. According to at