IIRC, there are some indications that life on Earth is really, really weird & varied due to the Moon's tide. Which was a lot higher and more frequent back then. Not 'million monkeys accidentally writing great prose' scenario, but a zillion tidal pools 'ringing the changes', rinse & repeat, rinse & repeat, twice a shorter day...
( ~12 hrs when first evidence of life, stuck at ~21 hrs for much of Pre-Cambrian due atmospheric resonance... )
Per multicellularity: Protists, ranging from slime-mould to mega-seaweed, show what can be done without going full-on Eukaryotic...
Tangential, the disconcerting discovery of mega-viruses, some larger and more complex than bacteria, mean definitions of 'Life, even as we know it', gets kinda fuzzy. Once 'obligate parasites' such as, yes, Covid are classed as 'Alive, sorta', they're better seen as honed-down 'spore-kin'...
Here's food for thought:
Chemists at Scripps Research have made a discovery that supports a surprising new view of how life originated on our planet.
phys.org
fair-use quote:
Discovery boosts theory that life on Earth arose from RNA-DNA mix
by The Scripps Research Institute
In a study published in the chemistry journal Angewandte Chemie, they demonstrated that a simple compound called diamidophosphate (DAP), which was plausibly present on Earth before life arose, could have chemically knitted together tiny DNA building blocks called deoxynucleosides into strands of primordial DNA.
The finding is the latest in a series of discoveries, over the past several years, pointing to the possibility that DNA and its close chemical cousin RNA arose together as products of similar chemical reactions, and that the first self-replicating molecules—the first life forms on Earth—were mixes of the two.
/
If I've understood it, they reckon chimeral RNA+DNA combinations hit the 'sweet spot' between function and stability...
This suggests that RNA+DNA+DAP offer a fast-track to recognisable biology. I remember
just enough chemistry to not rule out exotica such as sulphur / ammonia / silicon etc, but I reckon they're rare by comparison...
Doppler and transit surveys suggest there are many 'super-earths' and 'sub-neptunians' in what we call the 'habitable zone' (HZ), while orbital spacing suggests terrestrial-sized planets are far fewer. Given tidal-pool scenario, I'd suggest a plausible common cradle for life would be tidal-stirred mega-moons.
Corollary may be that our solar system does not appear to tick the necessary boxes for life emergence. Our disproportionately large Moon represents a 'limiting case' of such algorithms...
I follow
http://www.recons.org/ as they study local stars, both 'because they're there' and as a population guide to further stuff currently below detection thresholds.
Beyond immediate neighbourhood, 'there is a lot missing'. Not 'Dark-Matter' per-se, just too dim or un-resolved or Sin(i) thwarts doppler.
That aside, I reckon the nearest candidate for tidal-pool life may be tau Ceti. There's a big planet in the HZ, but mass uncertain due poorly constrained Sin(i).
Beyond that ? For every star with a transiting HZ planet, there'll be a dozen without. And of those, most will lack a 'tight' Sin(i) doppler...
Roll on decades of doppler data to figure orbital interactions and progressively constrain masses, until direct-imaging 'Planet Finder' mega-instruments come on-line...
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I'll not dip even a toe into FTL beyond obligate mention of Alcubierre's possible, yet apparently impracticable loop-hole...
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How far to nearest 'life' if none at tau Ceti ?
I reckon 30 ~~ 50 LY.
ET ? 100 ~~ 200 LY, perhaps much, much more...