Comment by fnordpiglet | Hacker News Reader

Comment by fnordpiglet | Hacker News Reader

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Scientifically the only life I can prove exists is on earth. We have found no evidence of life in any form anywhere. It’s totally reasonable to believe that may in fact be the case. The statement that it’s geocentrism makes the supposition that it’s ego that drives assumption of life only on earth. However if life only exists on earth, we would necessarily be the ones observing the empty universe.

A distinct possibility is that it takes a long time and very unique situations for life to evolve. The first life in the universe would look out at a lifeless universe. Life may later develop, and we are the first. Maybe life develops here first, and ejecta from our atmosphere seeding the space we travel through spreads it through the galaxy and the universe.

Maybe life existed everywhere during the Goldilocks period of the universe and has died out almost everywhere and we are the last ember.

But the only evidence we have for any of these theories - literally the only evidence - is that we are alone.

But I am glad we keep looking to prove that wrong.

Just a few decades ago it was absolutely correct to state that:

    Scientifically the only planets I can prove exists are here in this solar system. We have found no evidence of planets anywhere else.

I question whether it was then totally reasonable to claim that it was likely there were no other planets anywhere.

Today, of course, we are over run with evidence for exo planets.

There is a pretty significant gap in the implications of the existence of exoplanets and in the implications of the existence of exobiology.

Prior to the detection of exoplanets, there was likely still a general consensus that they probably exist, because that didn't really have any implications for our model of the universe. It was understandable that the technology of the time was just not capable of detecting things that small.

The question of life becomes more complicated because what it means in terms of detectability is completely different depending on the conditions. Depending on how common it is, things range from it being weird we haven't detected any yet to it being so rare that our existence is indeed special.

> to it being so rare that our existence is indeed special.

Which is possible but hardly reasonable . . .

Many in STEM would argue that it's reasonable to assume we're not at all special.

Life may not be "special", but we (our lineage) has gone through a few demonstrably evolutionarily rare events to get to the point we are.

The question is whether there is life elsewhere, not whether we have replicants "out there".

That said, the entire universe as is appears to be in incredibly rare event, moreso than mere evolution.

I kind of meant "we" as "intelligent life" capable of astronomical science.

We have no idea how rare the universe is because we can't compare it to anything. We can compare terrestrial species to all of the other terrestrial species we know of. This shows that some evolutionary trajectories and forms appear to be more or less frequent outcomes.

> We have no idea how rare the universe is because we can't compare it to anything.

Good luck floating that past your typical theoretical astrophysicist, there are several quite different approaches to taking a stab at that one - all fall into can't be resolved either way basket though, I see your point.

fnordpiglet mentions the rare earth notion, I first came across that in the mid 70's reading an Asimov non fiction essay collection The Tragedy of the Moon which raised the importance(??) of having a moon to create tides to create intertidal zones to nudge life from water to land.

https://en.wikipedia.org/wiki/The_Tragedy_of_the_Moon

There's a long chain of chance that lies behind ourselves arriving where we are ... the argument can still be made (as it was by Douglas Adams) that "The universe is big. Really Big."

The latest JWT images convey just a smidgeon of how big with high res images of tiny arc areas of the night sky packed with tiny lights that are each galaxies the size of the milky way and more.

That's a lot of rolls of the dice out there.

The space is big, but time is vast too. There was a time in the universe when the entire universe averaged a temperature conducive to life and there was oxygen, carbon, and other crucial elements available (although not as plentiful as now). Life could have formed then, and largely died out. In fact life may only pop up rarely in both space and time, so rarely that it’s unlikely two planets have life within a detectable distance at the same time. In fact it’s even possible a highly advanced civilization formed on the earth many millions of years ago, and at those time scales all detectable traces of its existence would be wiped out. The scales of time and space are so vast we fail to comprehend how infinitesimal our scales are and make huge assumptions about what’s plausible based on our scales projected to universal scales. That’s geocentric!

Also, possible doesn’t mean plausible. Objects can teleport to the moon through quantum principles it’s just so unlikely it’s never actually happens in reality. Life may be such a vastly implausible thing that our existence is a miracle so improbable it beggars the imagination.

In the universe we inhabit, what does rare mean? I think we think it is rare but we have no concept of the scale of the possible interactions.

That's the entire point of the fermi paradox.

The reasonable assumption as with most things is that we aren't special, yet the data increasingly does not appear to reflect that. Unlike with detecting exoplanets, blaming our sensors only makes this discrepancy worse.

Unless you're trying to make the argument that we haven't found life because we're looking for specifically Earth-like life, in which case I'd just say that it's more rational with our current technology to focus on the kind of life we definitely know can exist rather than hypothetical biochemstries we can't realistically test. It isn't even as if the conditions we're setting are especially extreme, a planet in a goldilocks zone of a relatively stable star with an atmosphere and signatures of water and potentially significant amounts of oxygen.

The Fermi paradox assumes detection | communication is desirable | possible | recognisable by us.

It relates to intelligent lifeforms that show themselves in ways we can recognise.

It has little bearing on the question of life elsewhere - a starfish orbiting an exoplanet counts here.

Fermi was a little naive on the "space is big | communication is hard" front - before the James Cook expeditions life existed in Australia and yet the British monarchy hadn't received a single missive by Royal Mail from any of the numerous nations within Australia.

The methods of signalling long distances that we're aware of require focus and|or vast amounts of power and extremely long travel times; focus requires us to be targetted over a staggeringly large number of other solar systems, weilding vast amounts of power requires tech able to do so and not find other more efficient means, etc.

Those communicating across galaxies are doing so in ways we do not yet recognise, those with civilisations that cause their own suns to give them away are yet to be found as we have barely starting looking at a fraction of all the systems there are out there - JWT is good but it's barely been up a day in cosmic terms and there's much left to look at.

The Fermi paradox isn’t what I would point to. It makes a lot of assumptions.

The rare earth hypothesis is much more rooted in first principles. The earth has a very rare combination of factors all of which are crucial to life as we know it, and likely anything we could recognize as life due to the factors life requires for maintaining its complexity and ability to self replicate and perpetuate. These are not limited to the specific nature of carbon, water, and oxygen in the Goldilocks zones, the necessity of a magnetosphere, in a very specific galactic structure in a specific part of such a galactic structure, making the specific envelope of Sol and earth with its unique tectonic geology, etc, all of which are literally necessary to evolve life. Other forms of life are theorized (silicon based, etc) but they have almost impossible requirements to assemble into structures complex enough with enough flow of energy without so much energy they fall apart. Every theorized xenobiology other than the one we have is likely impossible for pretty fundamental reasons. This doesn’t mean we have exhausted all possibilities or that nature won’t surprise us in crazy ways beyond our imagination, it just means life is almost certainly MUCH MUCH more rare than drakes equation lets on.

https://en.m.wikipedia.org/wiki/Rare_Earth_hypothesis

Again, I’m not saying life doesn’t exist outside earth. I’m saying we don’t know and despite really hard efforts to approach extraterrestrial life from every possible angle has been fruitless so far, even to the point we have no theories of life’s origins, how to detect life, and no open avenues that have any hope of such a discovery. At the moment it’s feeling less likely we will discover life outside the earth before we can reverse time (as we have done in simple time crystals). That should be daunting to our blind faith.

To my mind this should weigh on us as a burden. As long as we believe life exists elsewhere the loss of life on earth is sad, but ultimately inconsequential. If we are the seed of life in the practically observable universe, then we are the shepherd of the most amazing thing in all of creation. We have a responsibility to tend it, and IMO, spread it as far and wide as we can such that the universe does team with life and for the rest of all time life never feels alone.

Yet that proves nothing. I’d point out that the fact there are multiple planets around our own star and the theory of how the universe evolved predicted planets around other stars with near certainty, and we even had an idea of how to detect them it was just a matter of a sensitive enough instrument and computational techniques.

We have nothing equivalent for life. But not for trying, we absolutely have, quite a lot with many techniques. But yet, nothing. We don’t even have a theory for how life emerges that’s very advanced or verifiable.

I’m not saying we are alone. But the fact we exist doesn’t prove other life exists, and it doesn’t mean life is plentiful. If there were one person left on earth, they would observe a planet and assume there must be more people because how could they possibly be alone? Yet, by construction, they are. That incredulity doesn’t change anything.

I’m not asserting we are alone, and I believe we aren’t. But just pointing out our belief proves absolutely nothing, and holding the opposite belief doesn’t mean egotism. It’s actually the most rational belief given all evidence that we are alone.

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