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Comment by estimator7292 | Hacker News Reader

Good news: the primordial oceans were so vast (literally planet-scale) and persisted for so long (millions to billions of years) that you can run a trillion trillion individual random reactions.

You are being severely restricted by your imagination. You seem to have presupposed that random abiogenesis is impossible and reconstructed the facts to support that claim because you can't conceive of the alternative.

Planets are really, really big. Any one chemical reaction is on the scale of molecules. If you let those figures compound for a long time, the number of total reactions gets very, very large. Far larger than you imagine. Many times more.

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Still the wrong question. Life didn't start by brute-forcing the combinatorial cliff of RNA. I'm a fan of metabolism-first, or membrane-first. It was almost certainly thermodynamically favored the whole way.

The probability space of a 140-nucleotide chain is 10^84. The estimated number of atoms in the universe is 10^80. The hypothesized RNA self-replicator is far simpler than the 238,000 base pair archaeal genome. But how are they formed? Even the most favorable prebiotic lab conditions have only produced short nucleotide chains. Direct chemical synthesis only recently achieved chains over 1700 nucleotides long [1].

1. https://www.chemistryworld.com/news/first-direct-chemical-sy...

To go through all 10^84 possible combinations in a billion years, around 10^67 combinations would have to be "tried" per second. So yeah, it doesn't seem feasible to have one and only correct combination of 140 nucleotides spontaneously appear.

But if the "solution" could be composed of a couple of separate smaller parts, that would be stable and linger for a long time, it would be much easier. 40 nucleotides have 10^24 combinations, so only 10^7 tries per second would be needed... over a billion years. And all of the necessary parts would need to be created and then meet in the same place and somehow combine. So, still not easy, but this case doesn't sound so outrageously improbable.

In the end, maybe it is extremely improbable for life to happen, and only one in 10^n suitable planets develops life, and Earth was just very lucky to experience this peculiar phenomenon.

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