Comment by aethertap | Hacker News Reader

Comment by aethertap | Hacker News Reader

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> If there ever was a self-replicator, it has long since disappeared.

This is something I've wondered about ever since reading "Life's Ratchet" - if it was possible back then for a molecule to be self-replicating, then it seems like it should still be possible today (maybe with a different molecule), and therefore it seems possible or even likely that it's already happening all the time all around us. It's fun to think about seeds for new evolutionary paths being generated constantly at a scale so tiny we can barely perceive them. Maybe we will start finding instances of replicator molecules in all sorts of places once we know what to look for. If we master the chemistry to the point where we could design replicators for other places, we might even be able to kick off life in the nicer neighborhoods of our solar system.

Life scavenges a lot of the available chemical energy, making it less likely for a replicator molecule to interact with the necessary raw materials.

edit: It also might tend to scavenge replicator molecules themselves.

Definitely true, but if we just classify "self-replicating molecules" as life, they become just another coexisting organism in the mix of billions, perhaps scavenging some form of energy that's unsuitable to larger forms. We've only recently developed the ability to observe things at that scale, and it's still a very fiddly process as I understand it, so the idea that there is undiscovered molecule-scale life interacting with larger-scale life doesn't seem too far-fetched to me.

The most interesting answer that I hope comes out of this research is how sensitive the process is that leads to the creation of these molecules. If it's robust and simple, we can expect to find life scattered all over the universe. If it's extremely dependent on conditions found only in a narrow window of time on Earth, the picture is probably much more lonely.

Yes, the semantics quickly starts to get in the way.

I suppose you can look at viruses as replicator molecules that have adapted to a (relatively) cell heavy environment.

That first molecules appeared in an environment with much stronger ultraviolet radiation and temperature gradients at the sea, to power it. Without free oxygen to burn organic molecules and consequently, with plenty of simple organic composts free to reorganize in lots and lots of ways.

That earlier replicator is probably not here anymore.

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