Phosphorus, the origin of life, and the Fermi paradox

[arkuat]

So for a long time now, I've been poo-pooing the idea that life originated in shoreside tide pools, because I had adopted the opinion that life originated in deep suboceanic volcanic vents.

But it turns out that life probably formed before the ocean was even fully formed (i. e. early in the stages in which Hadean Earth was still outgassing lots of water and/or hadn't received all of its cometary intake yet), so it looks like the actual truth is somewhere in between the two ideas: lakes and ponds forming on the surface of fresh hot lava on top of barely-formed crust VERY early in the stages of cooling. It's a little like an underwater volcanic vent, and it's a little like a tidepool!

Here's an interesting paper that helped lead me to this conclusion:

Toner, J. D. and D. C. Catling (2019), A carbonate-rich lake solution to the phosphate problem of the origin of life. Proceedings of the National Academy of Sciences, 1-6. DOI: https://doi.org/10.1073/pnas.1916109117

(ETA: for those who don't know, phosphorus is needed for ATP and ADP, which all living things (yes, all) use to store and deploy energy internally, and also for RNA and DNA (yes, all), which you probably know about, and is also needed for cellular and intercellular membranes (again, yes, all such membranes in every organism) in the form of phospholipids. So, about as fundamental as carbon in its own way, but much less common than carbon. Also, it's a lot harder for stars to make than most atoms as light, for nuclear astrophysics reasons that I've read about but barely understand myself.)

And here's a youtube video that got me thinking about the whole phosphorus problem (including the problem of its nucleosynthesis), and suggests it as the resolution of the Fermi paradox:

https://www.youtube.com/watch?v=oPU9jeQbTOU

Looks as if we may have gotten over the Great Filter hump a long damn time ago. Unfortunately this means that aliens are gonna be pretty scarce, and it definitely shores up the rare Earth hypothesis (i. e. the Solar system is probably unusually enriched in phosphorus).

Comments

[arkuat]

Yeah, I've been wondering about that "product of production and dispersal" thing for various elements for many years now (mostly because of Fermi paradox), but don't have as many useful tools for doing so as you probably do.

Mostly it has been an occasional search for freely available papers on nucleosynthesis that use the word "kinetics" in its chemistry sense, but in the context of nucleosynthesis (and dispersal) rather than chemistry. Doesn't come up much, as I'm not sure the chemistry sense of "kinetics" has crossed over into nucleosynthesis astrophysics at all. Few seem to think there is enough data gathered yet for anyone to have firm opinions about such things anyway, is the conclusion that I've drawn so far.

Oh, yeah, and metallicity gradients! Finding out what I could about metallicity gradients was the most fruitful course for a while, but it turns out not that much is really known about them yet. I mean, all the theories are controversial. The galaxy people get very uptight about them.

[quadong]

I don't think that nuclear physicists use the word "kinetics" in that sense, or not often. There's a lot of work being done these days to measure nuclear reactions thought to be possibly important in stellar nucleosynthesis. It turns out the tricky part (one tricky part, anyway) is that the energies in stars are much *lower* than what we usually use in the lab. As you might expect, this means the reactions don't happen as much. They become important in stars because stars have a lot of matter and burn for a long time. To see the same reactions, at the same energies, on earth, people do counter-intuitive things like building small particle accelerators underground, because the reactions are so rare that the background on the surface would be overwhelming.

[arkuat]

Now that last bit is some really cool stuff that I had no idea about. Thanks.