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Re: Physics Concepts

Unread postPosted: Sun 13 Sep 2020, 15:31:33
by Subjectivist
dissident wrote:Understanding life is dependent on understanding organic chemistry. It is clear that RNA and DNA are a class of "anti-entropic" chemical reaction products where simpler organic precursors assemble into more complex and functional products. It is the actual evolution of this part of organic chemistry that is interesting. Self-replicating molecules appeared before any life. Whether a substrate played a role is not clear but would be likely since it would increase the probability of the chemical system evolution in the right direction. So hydrothermal vents playing a role is not "zero evidence" hypothesis. A catalytic environment provided by the surface of complex mineral solids would be a cheat on the time needed to sample enough of the reaction phase space to find the Gibbs free energy minimum that gives rise to self-replicating molecules.

The second stage is how these self-replicating molecules transitioned into life. This is another evolutionary processes. But it is also microphysical. A cell looks in many ways like a liquid aerosol particle with dissolved hydrophilic organics and a shell of hydrophobic organics. So it is plausible that self-replicating molecules evolved in an environment that looked like a cell for millions of years. Evolution inside mixed organic aerosol particles makes sense since that would be a sheltered environment compared to being dissolved in sea water. It would also be a confined environment promoting the recycling of chemical products.

Again hydrothermal vents are possible zones with sustained "aquasol" production (the physical properties of such particles would be the same as the air borne variety). Vents are sources of organic molecules and not just inorganic mineral solutes.

Anyway, life of some form is basically inevitable on any planet that has any chemical resemblance to Earth and there are vast numbers of such planets and even moons. It would not be a surprise if fossil life was found on Mars since it had oceans in the past.

Does this mean you expect to find life deep in the oceans of Europa and other satellite bodies where tidal heating causes or is at least expected to cause deep ocean thermal vents like those found on Earth?