Comment on no chances for life around red dwarfs
Paragone@lemmy.world 10 hours agoMere-ideas, but…
there seem to be one hell of alot of the things, so therefore some must have captured rogue-planets, after they calmed-down…
that would mean that the atmosphere-stripping might not be universal for all planets orbiting them, only for the planets that orbited them when they were young red-dwarfs…
Being tidally-locked may mean that not having any Van Allen belts may be irrelevant: the radiation they’re being bombarded by is coming from their sun, & life could evolve on the opposite side, having warmth, & maybe photosynthesis at the daylight-horizon?
Swift caught a red-dwarf emitting a flare 10k times more powreful than any we know about having been ejected by our Sun … but we’re looking at zillions of stars with our satellites, whereas we’ve only got a few decades of satellites watching our sun: there’s a measurement-disparity there, that is significant.
universe has surprised ALL of our assumptions about it, through the millenia… & the ONE rule on Earth for where life is, is: IF life CAN exist in some niche, THEN it does. Period.
Stratospheric bacteria with error-correcting-code DNA ( 4 compartments, each with about 1/3rd of the DNA, so it corrects radiation-induced-damage before dividing into daughter-cells, sorry I can’t remember where I read that, it was a couple decades ago ), bacteria eating bedrock, down where it’s too hot for anything else to live, etc…
To presume, as we normally do, that universe’s rules for life are different on Earth than everywhere-else, is … neither evidence-based nor correct-reasoning-based.
Therefore, betting that no red-dwarf-orbiting planet has any life on it … isn’t a bet I’d do.
That most such might be lifeless, I’ve no problem with that.
But any time we assert that “there’s no life” in an entire-category of universe’s places … that’s just prejudice, from what I can see.
There is some, indirect evidence that microbes used to live on Mars ( chemistry that has no other obvious explanation, e.g. )…
& that would indicate that life’s actually a normal-default, but that we evolved too-late to encounter Mars’s life…
Oh, & the flaring thing: being closer to a star makes flaring much more dangerous than it is to us: the energy-density at double the distance ( of the flare, between its sun & its planet ) would be 1/4, right? ( distance-squared ),
so closer would be massively more likely to be clobbered…
but … universe consistently surprises our assumptions, so I’m still holding-to the suspend-judgement, only speak for the majority, not for all, position.
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We should not presume either that all life is the same as life on earth. There are combinations of a great many different elements and molecules that could sustain life other than carbon and water and whatever. There could even be life on super hot places.
Of entirely different elements and molecules. Not saying it’s likely. I have no idea. Nobody does. And anybody that says they do, is either lying or wrong.
What 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.
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.
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).
*a lot.
wonderingwanderer@sopuli.xyz 4 hours ago
Now that’s cool to think about. What if there’s a large ring of life around the daylight horizon that hosts complex organisms (would plant-like organisms have red chlorophyll?), and to the sun-facing side everything becomes a constant, immense blare of red light, x-rays, and UV radiation; and to the dark side is constant darkness broken only by the stars, and maybe some fungal/bacterial lifeforms and stuff that can feed on them.
What color would the horizon be? Like the “sunset” of a red dwarf, would it shift to blues and greens and purples or just be invisible?