What might cell membranes look like on Titan?

[Arsenic&Lace]

Intriguing. I wouldn't be surprised if water turns out to be the de facto solvent of life. Why is it so difficult to probe alternative chemistries? I can see where the forcefield parameters for abnormal chemistries may be poor, and we can't even fold most terrestrial proteins much less a protein composed of an entirely new chemistry, but that's all computationally. Empirically I would think things might be different.

 

[Jimster41]

This is clearly all speculation, but it's fun speculation, and for me at least as well as others probably, a part of the learning process - particularly because it keeps the excitement of imagination in there to lubricate the real (hard, dry, and unforgiving) science... which is of course, work that must get done.

Although it allows the outcome of whatever thermodynamics might build from alternative "cells" to drift farther from anything humanoid, it seems to me like the question should start with things like - What are the minimum functional requirements of a humanoid "eukaryotic?"cell? How tied are those to the physical chemistry they evolved in? What alternative construction paradigms, if any, given different chemical contexts (like Titan), could achieve comparably outstanding entropy production? Is rate of entropy production, or something similar a good metric for assessing the "complexity carrying capacity" of various physical chemical dynamics. Is complexity, or some sort of energy flux density a good general description of what we are looking for when we look at the stars and mutter "life?"

At the end of the day ours could be the only, best one, but it seems a strange set of constraints with which to start.

Also I think the question mentioned above about how computational exploration may be harder or easier than actual exploration of the configuration space of the periodic table over time and energy integrals, is a great one.

 

[Arsenic&Lace]

Well the reason I want to do science is because it's fun, even if it involves lots of grueling debugging, disappointing failure, and grant writing. So speculate away.

I wonder if potential entropy production can be deduced in some way from the chemical composition and thermodynamic conditions of a system. Jeremy England has papers for generic physical systems on similar topics IIRC.

I think if good progress could be made on critical dynamics and rationally parameterizing forcefields computational exploration would be viable, but at present both problems seem stubbornly out of reach.

 

[rootone]

Yes, but you would want to be clear about what is computationally possible, and actual repeatable measurements.
I guess that's why there are theoretical scientists and experimental ones though, nobody gets it all their own way.
I certainly will not rule out the possibility of life forms defined by nylon shell.
In fact I saw a few walking through my local town yesterday.

 

[Jimster41]

I'm reading this paper by England now, forwarded to me by @techmologist.

http://www.englandlab.com/uploads/7/8/0/3/7803054/2013jcpsrep.pdf

his derivation of non-eq 2nd Law reminds me of the language of evolutionary dynamics. I think it's correct to say he is defining the entropy of the "heat bath" containing an organism with potential microstates, to be the conserved quantity from which the fitness function (probability of propagation, or durability) of those microstates is derived. This seems pretty elegant... and sort of simple.

[Edit] It looks like that is more attributable to G.E. Crooks

https://www.amazon.com/dp/0674023382/?tag=pfamazon01-20