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DF General Discussion / Re: How low could a dwarf go underground and still be able to breathe?
« on: August 22, 2018, 09:42:57 am »Food webs and energy pyramids are basic middle school science. Literally all life requires an energy source to continue to function. This is because life is essentially an energy transfer system where by kinetic (light, motion, sound, heat, etc) and potential energy (chemical) are transfered back and forth. This system requires a constant input of new outside energy.
Or a store of old energy that has not yet been depleted. On Earth, crustal chemosynthetic bacteria and archaea that live in basalt have some pretty exotic metabolic pathways, and in some cases have access to stores of energy that are substantial enough to possibly stretch past the lifetime of the surface biosphere. (It is not clear if the reactions involved can be sustained for long once the Earth is no longer capable of supporting surface water, and plate tectonics, however.) In other real locations (e.g. Io for a dramatic case), tides and related orbital processes can produce heating over long enough periods to be relevant for life.
The "old energy" as you say is still an input of outside energy. In the most basic sense the system boundary is the cell membrane.
Regardless, you are talking about bacteria. Nothing the size of a dwarf could subsist on such a limited amount of biomass.
As to tidal heating (ala Europa), it remains to be seen if that particular hypothesis pans out. There is as yet no evidence to support the claim that complex (multicellular life, like a dwarf) could exist in such an environment.
Personally, I think that there is a high likelihood single celled organisms exist on solar objects such as Europa. Not sure about anything much more complex.