Humanity isn't likely to extinguish itself, writes SETI scientist

This book covers the topic more extensively:

It claims a 19% chance of extinction by 2100.

(Personally, I think we’re beyond the great filter [which I think was the formation of complex animal cells; something which, as far as we know, only ever happened once])

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Perhaps they are taking into account the human inability to complete any collective action competently.


GRBs are a statistically negligible certainty. The odds of one wrecking the biosphere before we do are basically of interest only to astrophysicists. We are far more a danger to ourselves than the universe is.

And if we do somehow survive the next century, let alone the subsequent epoch, the universe probably has more to fear from us, or at least from our reckless disregard for consequences.


There is a finite possibility of a galactic version of “the world is so big, and we are so small, surely nothing we could do would impact it in any significant way!” If we survive the next (?) century or so that possibility rises to where any SETI-relevant civilizations out there should probably take notice.


An important thing to remember right now:

There is urgency, but we have agency.
—Dr. Mann

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All in all, a GRB within a few kiloparsecs, with its energy directed towards Earth, will mostly damage life by raising the UV levels during the burst itself and for a few years thereafter. Models show that the destructive effects of this increase can cause up to 16 times the normal levels of DNA damage. It has proved difficult to assess a reliable evaluation of the consequences of this on the terrestrial ecosystem, because of the uncertainty in biological field and laboratory data.[120][121]

I’ve read elsewhere that there aren’t any nearby stars of the types that could cause GRBs.


I was thinking more along the lines of us loosing unrestrained Von Neumann probes on an expanding sublight sphere of of space - or some similarly catastrophically stupid act - and quite possibly in the process being the extinction event of non-engineering life that can’t defend itself, that is to say “primitive” life.

In the decreasingly likely event that there are civilizations such as we think of them in reach of such a sphere, they’ve probably been around a lot longer than we have, or at least will have been when that hypothetical extinction sphere reaches them, and therefore have taken or will take precautions against that eventuality. But to be clear, I don’t believe humans as we are will populate the universe in any significant presence. As we’ve amply demonstrated with Earth’s oceans though, we don’t need to be able to live somewhere to royally fuck it up.

We’re a pathogen, and if we want to keep our civilization and not be laid low, we have to find a way to stop being a pathogen. I have no idea if we’re up to the task. I hope so, but the current outlook is not good.


it’s unfortunate that some people actually use this language, making it something considered legitimate to argue about, but of course “not literally extinguishing humanity” is a ludicrously low bar to meet and should never have been the point of the global warming debate


That we know of, but we’re not certain what all the causes of GRBs are. What we do have a good idea of is how often the occur in a given volume of the observable universe, and therefore the statistically improbability of one threatening us.

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Miracles are believed to have happened by people who take third party accounts of anecdotal evidence seriously and then destroy surprising phenomena that exist quite naturally, however improbable.


On that note: I really, really hope we never find life, especially multicellular life, anywhere else in this solar system.

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Do NOT effing let the current US President hear ANYTHING about this. His takeaway will be that it’s fine to press the effing button.

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Well, there are probably a lot of filters really…

But realistically let’s call “intelligent life”: something which is able to achieve space travel. Let’s also say that life requires (outside of wild speculation for which we have no scientific evidence) conditions just like this planet: just enough water (not too much), just the right size, just the right distance, just the right generation of star, with a planetary body like Jupiter (which is unusual in it’s positioning). It’s a chaotic formula and as a result likely infrequent.

I postulate that this exists very infrequently. We’ve learned a lot about other stars in this galaxy and so far we found ourselves to be an outlier in many ways. Even if complex animal cells exist on other planets, they probably exist on a planet larger than ours; probably x1.5-2 so (they’re more common). Any form of life would likely never make it to space as it would require too much resource commitment to even reach low orbit (akin to building the pyramids).

Finding live aliens is fine. Finding ruins is… Not so great.

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This is from Nick Bostrom, a guy who thinks the Terminator movies are documentaries, so take this in consideration.


Live aliens, especially nearby, would suggest intelligent life is even more common than finding less intelligent lifeforms would suggest, while also leaving unsolved the Fermi paradox. I think that would be even worse evidence in terms of whether most of the filter(s) lie in our future or our past. I would much rather find primitive ruins than a modern civilization, and only animals, only single-celled organisms, or no life would be even more promising in regards to our own future prospects.


Environmental degradation will cause the global economy to fail, leading to poverty, starvation and war. In the event nuclear and biological weapons are deployed, the remaining population will gradually resume an agrarian existence.

Given all easily accessible supplies of energy have largely been consumed (i.e. oil), it is unlikely that there will be the capacity to build a second technologically advanced society, though remnants of what is currently available will continue to be used.

Humans would then likely go extinct in the next 100,000 years, however ‘Life on earth’ will continue to evolve and in several hundred thousand years the world will have returned to (more or less) normal.

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survival is setting the bar low.

even a full blown nuclear war between russia and usa would probably not completely eliminate humanity, but we’d be knocked back to pre-agrarian times and billions would die.

but we say it’s not survivable because there’s a certain personality type that if told nuclear war was “survivable” would jones for it

They have to be optimistic.

They spend their time looking for other life. Kind of difficult given the distances, and no idea how prevalent life is.

What will Greta say?

The presence of any life beyond the single-celled on Earth is an anomaly.
I’m not certain what point you think you’re making here unless you’re trying to imply that there’s some “natural” quantity of humans that the Earth should host.