On Earth, there are geothermal vents - heat coming from underground vents that support life at the bottom of the ocean where the sun cannot reach.
My question is, would this be possible to support life in the atmosphere of a planet as the only source of heat? I'm thinking of a planet with these vents dotted around the surface like oases, each one surrounded by teeming life (even if it's just basic vegetation or very simple animal life) in an otherwise cold and barren landscape.
Further to this, could they support a small communities? People didn't necessarily evolve there (perhaps space-travelling colonists crash-landed there or something).
There are one or more stars close enough to provide a twilight level of light but no heat. (Think outer planets) though the people, while as close to being human as possible, may have somehow superior or different vision to ours (e.g. different visible frequencies) so they'd be able to see just fine. The atmosphere would have a safe level of oxygen & other gasses so it could be breathed by human-like creatures and the indigenous life.
My question is, is this possible? What are the major drawbacks to this that would make it implausible and how can they be overcome (naturally, not with technology)?
- Would the planet's depths too quickly run out of heat as to support meaningful life on the planet? If so, how could it be "refueled" (e.g. frequent meteor impacts)?
- Would the heat just dissipate into the rest of the atmosphere and
become too thinly spread to support life? What natural forces could
cause it to stay localised?
- Would travel between the vents be possible without space-suits (like could the oxygen exist as a gas in the low temperatures between vents)?
Been thinking about this a bit more... My idea is to have just warm spots around the planet rather than the whole planet warmed by the vents. Could it work if the vents (at least the habitable ones) were at the bottom of deep craters in the ground? The idea is that the atmosphere fills in the craters, but is not really thick enough to extend above them. This way, no heat is lost through convection.