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Q & A: life we can't imagine

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Most recent answer: 01/01/2016
Q:
Could life exist in forms that we cannot even imagine? Are there any laws of physics that prohibit that? We're looking for microbes or microbe-like things on other planets and moons, but could life be much more ubiquitous than we ever thought?
- Andrew C Llewellyn (age 23)
Adelaide, Australia
A:

That's a bit of a trick question, since our knowledge of things we can't imagine is limited. Still, we know that our imagination isn't good enough for many tasks. Who could have imagined quantum mechanics if they weren't pressed into it by data? There's no reason to rule out the possibility of life forms of types we haven't yet imagined.

So far we've only poked around looking for life on Mars, which is not as different from Earth as most places are. It makes sense to look for some thing vaguely like life here. That's especially true since there have been enough pieces of space junk traveling between here and there that life in one place could have spread to the other.

Still, it's fun to think about different possibilities. There's strong evidence that early life here had a lot of horizontal gene transfer. In more familiar terms, that means it wasn't nearly as much organized into separate cell lines as we are now. (By "we" I mean us, plants, bacteria,...) Perhaps early on you could imagine some evolving chemistry without any cells, perhaps confined to little cracks in rocks. (There is a fundamental physics problem for that sort of diffuse life in a fully three-dimensional bath, in that things diffuse away without enough chance of returning for repeat interactions.) So maybe there could be something we'd call life that wouldn't have cells. And maybe there could be even weirder things that we haven't imagined.

Mike W.


(published on 01/01/2016)

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