Comment by adrian_b
Reproducing RNA without proteins has nothing to do with the necessity of peptides/proteins existing before any RNA.
Polymerizing nucleotides into RNA requires energy and monomers that can be provided only by an already living being with a functional metabolism.
That requires enzymes for catalyzing the chemical reactions that compose the metabolism, which must have been non-ribosomal peptides, before the existence of nucleic acids.
The main source of energy for the first life forms must have been the conversion of free hydrogen (dihydrogen) and carbon monoxide and/or dioxide into acetic acid (acetogenesis). An auxiliary source of energy could have been the gradient of ions that exists in hydrothermal vents. Both sources of energy have their origin in the oxidation of volcanic rocks by water, and the energy comes ultimately from the internal heat of the planet (because the volcanic rocks formed at high temperatures, where they are in chemical equilibrium, are no longer in chemical equilibrium in the presence of water after they cool to lower temperatures). At least for now, there is no known mechanism for the appearance of life elsewhere than on a planet with water, internal heat and volcanism.
Some people see that simple organic substances can form in any place in the cosmic space where there is not enough oxygen to oxidize them, so they assume that perhaps life could appear there. However that is wrong, because without a continuous source of energy all those organic substances will stay dead forever. The only suitable continuous source of energy is the internal heat of big enough planets, which will not cool quickly, because capturing the energy of stellar light requires very complex structures that cannot be generated spontaneously, but they can be only the result of a long evolution of already existing life forms.
>>>Some people see that simple organic substances can form in any place in the cosmic space where there is not enough oxygen to oxidize them, so they assume that perhaps life could appear there.
LUCA is considered anaerobic - any contact with oxygen would have killed it. However we do not know what were preRNA Life forms.
>>>However that is wrong, because without a continuous source of energy all those organic substances will stay dead forever.
Unless they are getting frozen and put on pause, like all the stable chemical ingredients can exist in your household.
>>>The only suitable continuous source of energy is the internal heat of big enough planets, which will not cool quickly, because capturing the energy of stellar light requires very complex structures that cannot be generated spontaneously, but they can be only the result of a long evolution of already existing life forms.
The only known life, that is known to me that can process stellar light are plants and animals, that have eaten plants and are getting sugar from their cells, that are integrated into their organism.
I am not sure what this text was compiled together from, but most of chemical processes that are happening on any planet does not require any stellar light. Initially all of matter was part of a Sun and when it went Supernova, it involved some stellar light, but after that, no need for that.
>>>The main source of energy for the first life forms must have been the conversion of free hydrogen (dihydrogen) and carbon monoxide and/or dioxide into acetic acid (acetogenesis). An auxiliary source of energy could have been the gradient of ions that exists in hydrothermal vents. Both sources of energy have their origin in the oxidation of volcanic rocks by water, and the energy comes ultimately from the internal heat of the planet (because the volcanic rocks formed at high temperatures, where they are in chemical equilibrium, are no longer in chemical equilibrium in the presence of water after they cool to lower temperatures). At least for now, there is no known mechanism for the appearance of life elsewhere than on a planet with water, internal heat and volcanism.
This also looks like something compiled from different thoughts. But, ok - in terms of Life originating on the planet, this is only more or less applicable to evolutionary stage of Life, that happened on our planet in thermal vents, and only when planet was stable enough for a Life to exist there as we have no idea if Life was on our planet already, before Theia merged into our planet and destroyed everything organic, which seems to have been the case. But the issue here is not so much if Life originated on our planet, but where all the previous organic forms evolved, which are considered much older than our planet and primordal soup that is needed to create Life simply could not have happened in thermal vent like you are supposing.
From what I have read, comets are excellent places for primordal soup to happen as one of the prerequisites for a Life. Whenever they are approaching Sun, there is water boiling and all the processes that are similar to what thermal vents would have, but with light in addition and plentiful of resources for Life to spring. Like I mentioned earlier, freezing over would not reverse chemical processes that ere happening during that boiling and in next approach they would continue and there is basically indefinite time for those cycles to happen and disperse whatever end products that were happening on comets whenever they were passing plants - not to mention if they would land on them. There is life, that can exist in atmosphere, so there is actually no need for a comet to hit a planet to disperse product from their primordial soup. So, generally comets are one of the stages for prereq of Life, where explosion of Suns to disperse their thermonuclear product is previous stage. There seems to be impossible for Life not to appear the way how Universe functions.
PS I am not challenging RNA stuff, but Life also includes preRNA Life, so while your POV in regards to RNA based Life seems to be ok, everything outside of those boundaries are not ok.