Would any form of complex life be possible near absolute 0? At least for my personal standards, the "life" merely has to be:
- a self-sustaining,
- self-replicating machine,
- with a "computer" / brain,
- that doesn't necessarily need to be cellular.
To optimize my search I have 2 tier-lists of goals based on what turns out to be realistically possible for both "mechanism" and "temperature", with the bare minimum for "mechanism" being artificially replicated metallic robots, and the highest tier being a possibly cellular, organic lifeform that automatically reproduces, heals, grows, and thinks sapiently. While the tier-list for "temperature" would preferably be as close to absolute 0 as realistically possible with reality's exact unaltered laws, and at least as cold as any possible complex computer can exist at, even if artificially constructed.
The solvent, if any:
My first thought was for the beings to be very similar to robots, taking advantage of the almost non-existent temperatures for a brain comprised of a quantum computer, but then I realized these beings would probably have to be built manually, which is acceptable, but is of lower priority than a cellular and self-constructing design, if that turns out to be realistically possible.
I then studied the basic mechanisms of cellular life and came to the possibly eroneous conclusion that complex cellular life would require a solvent to transport various resources, yet apparently only helium remains liquid at near absolute 0. This led me to studying for literally multiple hours, trying to find any information on the material solubility of liquid helium, on which I found almost nothing 😅 aside from the vague statement that "helium is a noble element and reacts with very little."
The energy / food source(s):
As for energy, my current best idea is for the lifeforms to derive energy from some sort of nuclear reaction, as both solids and 'apparently' radiation can easily exist near absolute 0, and the best specific reaction I've found so far would be the reaction of "free radicals" oxidizing pyrite into "sulfate" (whatever that is) and apparently iron oxide, although from what I've read, the iron oxide couldn't be used to build material or "flesh", so sadly it may be largely wasted as excrement.
The current ideas:
This brings me to my current best 2 ideas for possible complex life at absolute 0:
At best? A cellular creature that somehow has access to and swallows radioactive uranium, pyrite, and possibly some form of construction material based in carbon like calcium or proteins, deriving energy from the radiation/pyrite-derived sulfate, and repairing and growing tissue with the carbon or silicon or "whatever".
If possible, it circulates liquid helium through its body to transport nutrients, and either simply never excretes this helium, or drinks helium from natural reserves in its environment.
It would move around either by rolling using its spherical form occasionally pushed by two thick trunk-like arms, each with minimal surface contact with the icy ground, or by walking on two legs optimized for minimal surface contact with the icy ground.
At medium: a similar self-replicating cellular lifeform at some higher temperature, whatever turns out to be the lowest possible temperature to harbor complex self-replicating life.
At worst: simply an artificial robot with a quantum computer "brain", living off of nuclear reactions.