Ask HN: Why isn't anyone else bothered by the fact that life is only on Earth?

I am aware of the aestivation hypothesis (counter to Fermi’s Paradox), and I am also aware of the Rare Earth Hypothesis. What I am trying to understand is why more effort isn’t expended to determine the state of other life in the universe? Consider that the building blocks of life are biological molecules, which have been found in asteroids [1]. What bothers me is that we know that older Earth-like planets exist in habitable zones, or once had conditions which were habitable. But where are the microfossils, like we find on Earth [2], let along anything more complex, like unicellular organisms, or multicellular organisms? Even if you hypothesize some intelligent life form devastated the entire planet and its ecosystem, where is its fossil record? Ruins and garbage record? Or space garbage?

I am bothered by how improbable it is that even simple life forms have not been discovered anywhere else in the universe. The most reasonable explanation after you exclude something artificially forcing life to exist on Earth, or preventing it from existing anywhere else, is that we just need to explore the universe more, and grab samples from other planets in habitable zones. I really hope that more efforts are expended towards finding simple life forms on other Earth-like planets as the fact that life seems to be found just here in a place as big and wide as our entire system (the Universe) is really hard to believe, and keeps me up at night because it’s just so weird. From what I can tell, we need deep space autonomous exploration asap.

[1] https://scitechdaily.com/nasa-uncovers-lifes-building-blocks-in-asteroid-bennus-pristine-sample/

[2] https://www.science.org/doi/10.1126/sciadv.adk3208

How many other planets do we have the capacity to examine microfossils from? Being able to check out asteroids (qua bits of fragmented planets) for a very short time.

> I am bothered by how improbable it is that even simple life forms have not been discovered anywhere else in the universe.

The obvious reason is that our ability to look is extremely limited.

Could there be subterranean life surviving deep in Martian rock? We don't know, we haven't looked yet there yet.

Could there be life sustained by thermal vents in Europa's subterranean ocean? We don't know, we haven't looked there yet.

We've identified some habitable zone exoplanets. Do any of them have life? We don't know, we don't have the technology to tell. If we are talking about Earth-like multicellular life, you'd expect there would be some atmospheric changes, which we'd eventually be able to detect remotely via space telescopes (even if the current generation of space telescopes can't yet). But if we are talking about subterranean microscopic life – how could we tell without physically sending a probe there? So I don't think we'll know this century.

And surely there's many more habitable zone exoplanets out there we haven't identified yet, because our telescopes aren't good enough. And eventually we'll get better telescopes, and we'll identify more of them. But even then there will be many more that even those telescopes aren't powerful enough to identify.

There is life everywhere in the universe. Just because we haven’t find evidence doesn’t mean there isn’t life elsewhere in the universe. Till recently we didn’t even know that life exists in the depths of oceans near volcanic vents. We can’t even see astronauta footprints on the moon. How can we ‘see’ life on far away planets or astroids or whatever we haven’t discovered yet.

How would we discover simple life forms elsewhere in the universe? It's not impossible the Mars rovers could have have found fossils, but it's not like we've been to the 100 million other stars in this galaxy, never mind any other galaxy.

Our radio and other telescopes aren't good enough to detect life on other solar systems unless we get really lucky, though if we manage to get 1000 au out we could use the sun's gravitational lens to magnify other planets enough that would see continents, detect artifical radio sources, etc.

Interstellar travel is hard, maybe not even practical. It's one thing to travel to another star, it's another thing to travel to another star, create an industrial base, then travel to another star. And why would you be motivated? You might be alive, just barely, to get the news from the next star over, but not much longer than that.

The space colonization project that makes the most sense in this solar system (read it carefully to see why it strictly dominates everything that's been proposed) is

https://arxiv.org/pdf/2011.07487

I'd assume anyone who develops interstellar travel would develop that first, it would be suicide to plan to colonize an Earth-like world on the other end (might face severe biological incompatibility) but it seems a realistic plan to build something like that Ceres megastructure on the far side. In fact, if somebody developed D-D fusion they could exploit similar objects that are scattered throughout interstellar space which makes the hops between stars shorter but might mean they'd be indifferent to stars and dry Earth-like planets completely when they could, instead, gravitationally disrupt generic outer solar system/interstellar bodies (like Pluto) and make a number of small ringworlds or other megastructures.

If there's any evidence they haven't been here it's that Ceres is still there.