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simiones | on: A metallurgist's doubts about self-replicating probes
The thing is, while the universe is full of metals, it's not that full of the materials needed to sustain life (as we know it, at least). You can find metals and other inorganic compounds on virtually every asteroid, moon, and planet, and many comets even. But water and nitrogen and carbon are significantly rarer.

Plus, life can't survive more than a few minutes in space without metal encasings and electronic life support; whereas metal alone only requires life at a much longer time scale. So, while it may be possible to build a fully inorganic self-replicating fleet, it's certainly impossible to build a fully-organic one with any technology or chemistry we know about today at least.

torginus | parent | next
Actually the other way around:

https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem...

There's tons of Carbon, Nitrogen and Oxygen in the universe, but very little metals. Heavier elements are much rarer.

abecedarius | parent
In the outer solar system organics and water are abundant (and in the inner there are plenty of carbonaceous chondrites, admittedly not the most generic inner-system bodies).

Agreed that metals should unlock wider opportunities in the inner system where solar energy is more abundant. I just don't think it matters much, you need a good place to plant your seed; once you've built up to scale you can then build wherever.

(False that life dies in minutes in space; plus the engineers can invest in even greater error correction than radiodurans.)