[thaumasiotes]

> We will then need to figure out how to sequence the chemistry of of these lifeforms which may require us to redefine the definition of "life" altogether.

I don't see how; we don't have a definition of "life" to redefine. We basically operate on the simpler system of having a big list of things that are life -- everything is categorized as "alive" or "not alive" without reference to a general definition of the category.

[mcbits]

Currently the broadest definition of life would be something like: A self-replicating cellular structure having a metabolism to organize resource input and waste. "Cellular" lets us rule out things like fire and crystals, but viruses and RNA soup are also swept away.

I think if we found a population of some kind of self-replicating RNA analogues on another planet, it would be significant enough to revisit that "cellular" constraint. On the other hand, that definition is already so broad that we could conceivably build self-replicating 3D printers that would qualify as life.

We might also take a top-down approach and come up with a good definition of "ecosystem", and then define living things in terms of their role in an ecosystem.

[blacksmith_tb]

Well, we typically operate from general principles[1] which don't require any particular biology. But of course it could turn out that the biology was similar (if panspermia-style theories are correct, or even just convergent evolution).

1: https://en.wikipedia.org/wiki/Life#Biology

[anonymfus]

Everything we consider life now had a common ancestor, and this is de facto definition.