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> “Must be water based, since that’s what we know,” This one is an assumption, but it's a pretty good one. Equilibrium chemistry has a fairly narrow band of e

by bsder 2y ago

> “Must be water based, since that’s what we know,” This one is an assumption, but it's a pretty good one. Equilibrium chemistry has a fairly narrow band of energy in which things can be pushed to one side or the other without completely dissociating. A solvent is almost always required as a medium and water is about as "simple" as that gets. Sub-zero chemistries might work, but they would be much slower than water--life might take longer than the age of the universe to evolve. Molten chemistries don't seem to be able to hang together long enough to be reversible. While the "building blocks" of life might be different, given our current knowledge of physics, the probability that the solvent for life is water is likely very high.

vundercind 2y ago
Chemistry’s the limiting factor for most of it. You’ll need a lot of energy for complex life. The list of things that can naturally provide enough without having extremely-hostile side effects is pretty much limited to stars, and then only if you get really lucky in a whole bunch of ways. Then you need to turn that into chemical energy to actually do anything with it. That’s gonna turn useful chemicals from the environment into waste you can no longer use. If you’re lucky the waste is chemically useful, and if something can evolve to use it, maybe it can turn it back into what you need (happened with oxygen). If the waste isn’t useful, you better hope your planet’s recycling it somehow. Ideally with some kind system that adjusts with a feedback-loop so it doesn’t limit your growth too much. Our one example sure looks extremely fragile, in that if you mess with any of several things a little bit, you might still get life, but it’ll cyclically wipe itself out, or never be able to harvest enough energy to support complex life, or any number of other problems that end in not seeing intelligence arise.
- aaronblohowiak 2y ago
  Are we after the great filter?

by bsder 2y ago

vundercind 2y ago

Chemistry’s the limiting factor for most of it. You’ll need a lot of energy for complex life. The list of things that can naturally provide enough without having extremely-hostile side effects is pretty much limited to stars, and then only if you get really lucky in a whole bunch of ways. Then you need to turn that into chemical energy to actually do anything with it. That’s gonna turn useful chemicals from the environment into waste you can no longer use. If you’re lucky the waste is chemically useful, and if something can evolve to use it, maybe it can turn it back into what you need (happened with oxygen). If the waste isn’t useful, you better hope your planet’s recycling it somehow. Ideally with some kind system that adjusts with a feedback-loop so it doesn’t limit your growth too much. Our one example sure looks extremely fragile, in that if you mess with any of several things a little bit, you might still get life, but it’ll cyclically wipe itself out, or never be able to harvest enough energy to support complex life, or any number of other problems that end in not seeing intelligence arise.

aaronblohowiak 2y ago
Are we after the great filter?