Comment on no chances for life around red dwarfs
cynar@lemmy.world 10 hours agoWhat combinations are you thinking of?
Life on earth is based around Carbon chains. Carbon’s 4 bonds allows for a low of complex structures that would be hard/impossible for less bonds.
The only other viable option I know of is silicon. Unfortunately its chain equivalent has an extra reaction pathway with water. It would degrade rapidly if exposed to water, which is very common at the energies it would work at.
I’d be curious to look up any other viable options.
nomy@lemmy.zip 8 hours ago
Your comment made me go down a pretty fascinating rabbit hole, hypothetical types of biochemistry. You mentioned silicon, with something like ammonia or methane serving the role of water. Carl Sagan apparently considered Silicon and Germanium possible substitutes for carbon
The article also mentions non-green photosynthesis and that other colored plants could support photosynthesis and might even be preferred in places that receive a different mix of solar radiation than Earth. Science so is fucking cool.
cynar@lemmy.world 8 hours ago
Silicon’s conditions would make it difficult. It has far less inorganic precursor molecules to work from. It might work under cryogenic conditions, but that has a bunch of other problems.
The titanium one is new to me, and potentially interesting. My concern would be an abiogenic pathway. It might be able to form interesting molecules for life, but if they don’t appear naturally, then getting life started gets massively more difficult.
There’s also a hell of a lot of options with carbon based life. Earth life is VERY locked into a few variants with our base biochemistry. E.g. there’s no reason for particular RNA sequences to match particular Protein peptides. Yet it’s basically a universal thing. Even chirality is fixed, for no particular reason other than mixing causes issues.
I could potentially see a dual based life system working, effectively a more advanced version of how some creatures use metals to make shells etc, or how horns and hair grow. It could also provide a viable (though extremely convoluted) bootstrap process for titanium life, or something more exotic. Forcing life to change its core functionality however is apparently quite difficult, since no life on earth seems to have done so and survived to be detected. Rocky, in Project Hail Mary, would fall into this group (a carbon life core basically piloting a stone and metal mech).