What would the biochemistry of a vacuum dwelling creature look like?

I'm playing around with a story idea that includes vacuum dwelling intelligent life, but I'm not sure I understand the constraints of biochemistry I need to deal with.

There's lots of potential sources of energy and nutrients in space. Radiant energy from stars, the magnetospheres of planets, and so forth, but if if you want to GROW, you need sources of raw materials. Elemental Hydrogen is abundant in the solar wind, but I'm imagining something large (kilometer scale) and solid, which suggests it's going to have to eat something a bit more substantial. I was thinking comets, asteroids, perhaps filter-feeding on clouds of gaseous leftovers from novae and supernovae.

So, the question is, what kind of elements would be needed, and in what kind of quantities? I'm looking for detail in terms of the biochemical lifecycle processes involved. E.g. :extremophile bacteria rely very heavily on elemental sulfur for their metabolic processes (see link below). https://aem.asm.org/content/79/7/2172.full

EDIT: Really what I'm looking for is some help figuring out, based on what a creature like this has available to eat, what their biology would look like. what are they made out of, molecularly? Lots of Carbon? Something else? I'm not really sure what makes sense if you really try to Do The Math in terms of metabolic equations, and I don't have the masters degree in Biochemistry that would let me figure it out for myself.

EDIT the second: People are talking about Silicon, are there gaseous sources of elemental silicon or would this require Asteroid Munching?

posted over 6 years ago

Morris The Cat‭

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