| Sure, the problem of having a sample set of precisely 1 makes it dangerous to extrapolate too wildly ... but similarly, the absence of any other type of life on this planet, and our understanding of - and ability to postulate on - other building blocks viability, should not be dismissed because a carbon / water / oxygen arrangement is known to work. I think you'll really enjoy The Vital Question, as it covers a lot of what you seem to be interested in knowing more about. > Another problem is that the earliest fossils are 4.3 billion years old ... I thought the figure was a bit less that that - and referred to (disputed) indicators of life, not fossils per se, but the generally agreed upon earliest is dated at ~3.5bya. Nonetheless your point is understood -- some basic building blocks appeared 'spontaneously' over the space of 800,000 years, give or take. Conditions at the time are broadly understood, though of course not the details - and it's that ~ 800,000 years, plus the unknowable details of the environment, that make me think we'll never know for sure. At least not in the level of confidence that you appear to need - where the precise chemicals, with the right ratios, in the right solution, at the right pressure/depth, making whatever the first life form was (we don't know what that was, and likely can't ever know). Ultimately I don't think we need to know exactly how DNA, RNA, and cells came into existence - it'd be nice, sure, but there's no requirement for that likely unobtainable goal. Regarding filaments - I just searched on 'hydrothermal vents rna' and found a few likely links, including this one: https://astrobiology.nasa.gov/news/lifes-building-blocks-for... |