Possibly, we are the adaptation of life's earlier forms, which began not in water, but earlier, in volcanic or lava environments, or at the boundaries of water formation in extra-hot environments, while the world was cooling down, during some period of darkness after a volcanic eruption, or in what was then the north or south poles.
It is commonly accepted that life most probably started with thermophiles and that chemosynthesis is what started it all.
This not-completely-thought-through hypothesis, which I am proposing, says that in fact, it may have happened earlier than previously thought, getting energy from the existing hydrogen gas, hydrogen sulfide or ferrous ions which were abundant, and interacting with thermodynamically favorable premordial co2 to create organic chains with carbon.
Perhaps ATP/ADP, and amino acids preceded the C chains as organic matter, then when water came around, bingo! We got life as we know it?-- pashute, Sep 06 2025 Defining Life https://pmc.ncbi.nl...rticles/PMC3005285/For anyone else thinking of contributing, this looks like a good place to start... [VaquitaTim, Sep 13 2025] Silica deposit--earlier life sign? https://bmcplantbio...86/1471-2229-11-112Like sands through the hourglass, so go the daze of our whys [Sgt Teacup, Sep 14 2025] [+] for opening this sort of discussion.-- doctorremulac3, Sep 06 2025 I may be telling you things you already know but there has been an hypothesis that life first formed when organic molecules accumulated on the surface of clays. Another hypothesis, less popular, is that in the early Universe there was a phase during which molecules formed into microörganisms when the Universe was much smaller, the ideal temperature for the origin of life and contained more concentrated matter than it now does. According to that hypothesis, all life of the kind familiar here was distributed throughout space and later settled on various hospitable bodies, including Earth. If that's so, the kind of life in question would be similar to life today in that it uses water. The molecular clock hypothesis also seems to show that life using DNA, I think (possibly RNA if the RNA world hypothesis is also accepted), is older than Earth.
I tend to believe in panspermia because it gives a larger volume and more arbitrary reactions for abiogenesis than just the Earth's surface or oceans, or smaller regions such as geothermal vents or carbonate-rich lakes.-- nineteenthly, Sep 07 2025 This admits the possibility of lifeforms based on silicon, or copper, or sulphur at some time in a planet's evolution. What if these alternate forms died out when conditions favored exclusively water-based carbon meatbags, from the microscopic up?
On the other hand we may be the only sentient result of a chain of very unlikely accidents. Either way we may be screwed.-- minoradjustments, Sep 08 2025 Confining life to biochemical forms, which may not be the only possibility, carbon really seems to be the only option assuming no technological intervention. Allowing that would probably widen it to boron and silicon, but for that to happen some other form of life would have to arise first. Also, biochemically it probably can't do without phosphate as such a scarce element as phosphorus probably wouldn't have such a central role unless there was no alternative. But all that assumes that biochemistry is the only possibility. I think there are probably others: plasma, ionised dust, neutronium as in 'Dragon's Egg' and nuclear pasta. Life not as we know it - well, we don't know it, so maybe.-- nineteenthly, Sep 13 2025 Equisetum (horsetail) is our only extant example of biosilification, hinting at a silicon-based life form pre-dating Marvin* or Rosey*. So yes, I vote that this is a possibility based on all of the sand slung about Earth--ashes? remains? We may never know.
*Yes, yes, I know they are imaginary, as is Elon's self-driving car and household humanoid bot.-- Sgt Teacup, Sep 14 2025 There are lots of examples of biosilification. Nettle stings for example, and also diatoms, radiolaria and even cereal.-- nineteenthly, Sep 14 2025 The thing is, it seems like there was life on Earth at almost the earliest point it was feasible to exist. That is, on a geological scale, practically as soon as the earth had cooled down enough for there to be pools of liquid water, there are signs of some sort of primitive life.
The problem we have with understanding the origins of life is that the earliest evidence is all pretty indirect - the Earth is pretty active, and other living things naturally compete to scavenge the materials.
//It is commonly accepted that life most probably started with thermophiles and that chemosynthesis is what started it all.//
Not sure that the first part of that is true. Chemosynthesis, sure. The alternative is photosynthesis, which is quite involved. Thermophiles, though? There have been claims of early evidence of life around hydrothermal vents, but this is at the very least disputed. As I understand it, genetic analysis of the creatures currently living around these vents puts them as descendants of other deep-sea dwellers.
I like your idea of life in lava. I doubt it, though - because if it were a thing then, it could easily still be a thing /now/. The moderate-temperature lifeforms we know are certainly not going to be competing for the niche of living in liquid rock.-- Loris, Sep 14 2025 Just on the silicon thing, as far as I've been able to find out, all silicon in organisms is concentrated from silicic acid in aqueous solution and is in the form of silica, and I don't know how far back it goes but prima facie it seems unlikely to proceed the emergence of eukaryotes. There are no known examples of silicon compounds other than silica participating physiologically in living systems, although there are pathological reactions such as mesothelioma and some silicon compounds are endocrine disruptors.
It isn't accepted that life must have evolved from thermophiles. The idea seems to be that thermophiles evolved from organisms living in to us less extreme conditions, in carbonate lakes, occupying a new potential niche.
I do think it's possible life arrived here rather than evolved here for the reasons I said earlier, one of which is that it almost seems to have gotten here before it possibly could've done. As I understand it, the earliest traces of life are graphite inside zircons with a typically biological distribution of isotopes.
Panspermia: yes. Silicon-based life: no way.-- nineteenthly, Sep 14 2025 random, halfbakery