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Interstellar Extinction Event


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I've always wondered this, what would an extinction look like for an interstellar species? How would they all die out, how would any life they brought to their colonies survive, and could new intelligence evolve from the ashes? It seems almost impossible a species could go extinct if they can achieve interstellar travel, but things can happen.

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If they bored into another dimension for energy and the beings that lived there altered physical constants in our universe to extinguish their consciousness they could certainly go extinct regardless of how far they'd spread

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War comes to mind. Or terrorism. Most natural causes could be excluded on their own since they can't (reliably/targeted) hop star systems, but with human/alien help they could of course. Those would be my top 'most likely' options. Grey goo and/or rogue Von Neumann probes could be a less evil/intentional but still intelligence-caused option. Related to that, evil AI could do the trick (Roko's Basilisk?).

For purely natural causes anything that could wipe out an entire multi-stellar civilization is liable to destroy the entire universe. There's Strange Matter/Strangelets for example (think cosmic Ice-9). Then there's False Vacuum Decay (or a 'Vacuum Metastability Event'), basically a phase transition of the entire universe to a more stable quantum state.

There's the geometric cut-off suggested by eternal inflation theories, this gets a bit above my pay-grade in maths and statistics but basically, in order to make the probability calculations in quantum physics work physicists have to use some boundaries because in an infinite universe/multi-verse with infinite space-time every event happens an infinite number of times and therefor the probability of any event happening is equal to the probability of all other events happening, throwing sand in the quantum probability machinery. It has been suggested that these boundaries may actually be real rather than just a mathematical tool which would mean time would simply end some time in the coming 5 billion years.

Some people might suggest a galaxy collision/merger but the reality is that these events rarely involve actual stellar collisions, it would definitely change the night sky but it's unlikely it would wipe out an entire civilization assuming they are somewhat spread throughout their home galaxy.

Of course universe ending catastrophes aren't all that interesting to explore because there'll be nobody around to talk about it around the water cooler anyway. Besides the water has probably turned to ice because of the Ice-9. So my vote for the most likely cause would go to some form of sabotage/war/terrorism on an interstellar scale.

Assuming such a cause, some pockets would be likely to survive due to isolation, and although rebuilding might take a long time, that's only 'long' on human scales, not on cosmic scales. The science has all been done, it's mostly a matter of building back up to whatever level of development allows you to produce the presumably exotic materials needed for your interstellar engine magic before the whole story starts over again. This time with even more motivation to eliminate everyone else!

 

Edited by Beamer
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8 hours ago, Kerbalsaurus said:

I've always wondered this, what would an extinction look like for an interstellar species? How would they all die out, how would any life they brought to their colonies survive, and could new intelligence evolve from the ashes? It seems almost impossible a species could go extinct if they can achieve interstellar travel, but things can happen.

 

Have you heard of Krypton and Superman.

 

Fabulously smart and stupid Kryptonians were.

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Inbreeding depression/genetic bottleneck.

Or outbreeding depression.

I am skeptical any intelligent species-caused event could bring about true extinction. Just as nuclear war never posed a threat to humanity as a whole ‘cuz South America, Africa, and Australia, the likelihood of an extinction event would be even lower once planetary/stellar dispersal occurs.

The inbreeding/outbreeding depression would take a very, very, long time to manifest itself.

It’s such a huge timeframe that the other more likely possibility is that the species evolves into a new one.

9 hours ago, Kerbalsaurus said:

how would any life they brought to their colonies survive

Depends on to what extent these populations were introduced to the new lands. Are they roaming free in their own new ecosystem like Hawaiian hamsters or are they dependent upon care from the intelligent species?

9 hours ago, Kerbalsaurus said:

could new intelligence evolve from the ashes?

Unlikely. Intelligence needs very specific circumstances to occur.

9 hours ago, Kerbalsaurus said:

It seems almost impossible a species could go extinct if they can achieve interstellar travel, but things can happen.

Agreed, if an extinction event has to happen I would think it would be the genetic events I mentioned but I think it is unlikely.

That said, a species becoming a new one would technically qualify as “extinction” too.

Disclaimer: I am by no means a genetics expert, if there are any here please enlighten us further!

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Sounds a lot like a global extinction of specific species not related to a climate event.  In other words, wouldn't happen naturally.  A separate species hunting them all down across multiple star systems (like multiple continents) on Earth might be possible.  See the extinction of small pox on Earth.  Typically, if humans do manage to extinctify all members of a species on multiple continents, I suspect that only the last few were known historically, and some effort is involved for the last.

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2 hours ago, SunlitZelkova said:

Inbreeding depression/genetic bottleneck.

Or outbreeding depression.

I am skeptical any intelligent species-caused event could bring about true extinction. Just as nuclear war never posed a threat to humanity as a whole ‘cuz South America, Africa, and Australia, the likelihood of an extinction event would be even lower once planetary/stellar dispersal occurs.

The inbreeding/outbreeding depression would take a very, very, long time to manifest itself.

It’s such a huge timeframe that the other more likely possibility is that the species evolves into a new one.

Depends on to what extent these populations were introduced to the new lands. Are they roaming free in their own new ecosystem like Hawaiian hamsters or are they dependent upon care from the intelligent species?

Unlikely. Intelligence needs very specific circumstances to occur.

Agreed, if an extinction event has to happen I would think it would be the genetic events I mentioned but I think it is unlikely.

That said, a species becoming a new one would technically qualify as “extinction” too.

Disclaimer: I am by no means a genetics expert, if there are any here please enlighten us further!

I like what you've said. Of course, it's unlikely and intelligent species would evolve into another species, especially if they've achieved interstellar travel. Think of it like Humans. You need to protect the brain? Instead of evolving a harder skull, which could take thousands of year,s you could just make a helmet, something that could only take a few days. Of course, this doesn't prevent hard heads from appearing in our society, but that's a whole other conversation. Point is, unless genetic mutations are artificial, they most likely won't evolve out of existence. But that does give enough time for inbreeding, like you said. Also, if they can travel the stars *snap*, like that, than that could also lead to interplanetary superpandemic. Just coined that phrase. It'd be hard to treat this if it's on such a large scale, and could collapse society in a flash on cosmic time scales. There are a variety of things that can go wrong, and the scary thing is all that can happen to us one day, if we're not careful.

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3 hours ago, Kerbalsaurus said:

Of course, it's unlikely and intelligent species would evolve into another species, especially if they've achieved interstellar travel.

Exactly to achieve the interstellar capability, they should evolve into an advanced semi-biological species.

The human body itself is a colony of symbiotic monocellular species.
Not only because it can't live without the symbiotic bacteria in the intestines, but because the human cell is a chimera of a big stupid procariotic anaerobic protobacteria (the cell itself) and a whole bunch of its degenerated parasites like mitochondria and other its "organellas" (probably even the nucleus which makes it eucariotic) which are in fact parasitic intruders which had lost their other abilities and formed a symbiosis inside  the owner's body.
The owner cell life itself is probably just emulated by these symbionts. and it can't even breathe, the michodria are doing this for it. And they have their own genetic line totally separated from the cell genes.

So, the body itself is just a randomly formed and adaptively shaped piece of matter, and its optimization is inevitable for an advanced civilisation, because it doesn't need to climb on branches and gather bananas, as its body was designed for.

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3 hours ago, Kerbalsaurus said:

Of course, it's unlikely and intelligent species would evolve into another species, especially if they've achieved interstellar travel. Think of it like Humans. You need to protect the brain? Instead of evolving a harder skull, which could take thousands of year,s you could just make a helmet, something that could only take a few days. Of course, this doesn't prevent hard heads from appearing in our society, but that's a whole other conversation. Point is, unless genetic mutations are artificial, they most likely won't evolve out of existence. But that does give enough time for inbreeding, like you said.

My thing with evolving into a new species was more akin to how we are not Permian cynodonts anymore: so much time has passed humans* will not be humans anymore naturally. This would take millions of years. It isn’t something done to a species, it just happens.

My inbreeding depression scenario assumes that eventually there won’t be enough genetic diversity to sustain a healthy population and that it will wither and die. This would also take millions of years.

3 hours ago, Kerbalsaurus said:

Also, if they can travel the stars *snap*, like that, than that could also lead to interplanetary superpandemic. Just coined that phrase. It'd be hard to treat this if it's on such a large scale, and could collapse society in a flash on cosmic time scales. There are a variety of things that can go wrong, and the scary thing is all that can happen to us one day, if we're not careful.

Disease is a reasonable possibility, more so than destructive war alone I think.

Disease did contribute to the collapse of Native American tribes after all. I could see a “superpandemic” killing say, at least 50% of the population, plus another 25% killed in the ensuing chaos and conflict, which in turn paves the way for an inbreeding depression thousands of years later.

That’s not an arbitrary number, that’s roughly the degree of population loss experienced by the Coast Tsimshian Native Americans in British Columbia upon European contact and the ensuing epidemic (57%). Germany lost 15% of its population in the rather politically motivated WWI, if a pandemic disrupted food and other material supply chains and triggers wars for survival how many more might die? Meanwhile despite intermarrying with Europeans Native American populations still have lower genetic diversity compared to others. There isn’t any problem at the moment but what about 10,000 years from now? Perhaps there wouldn’t be such issues in real life for Native Americans via further intermarrying, but our scenario has humans/an intelligent species on its own with no outlet for an increase in genetic diversity.

As you say, scary stuff.

*Just using them as an example but this could apply to any intelligent interstellar species.

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4 hours ago, SunlitZelkova said:

My thing with evolving into a new species was more akin to how we are not Permian cynodonts anymore: so much time has passed humans* will not be humans anymore naturally. This would take millions of years. It isn’t something done to a species, it just happens.

My inbreeding depression scenario assumes that eventually there won’t be enough genetic diversity to sustain a healthy population and that it will wither and die. This would also take millions of years.

Disease is a reasonable possibility, more so than destructive war alone I think.

Disease did contribute to the collapse of Native American tribes after all. I could see a “superpandemic” killing say, at least 50% of the population, plus another 25% killed in the ensuing chaos and conflict, which in turn paves the way for an inbreeding depression thousands of years later.

That’s not an arbitrary number, that’s roughly the degree of population loss experienced by the Coast Tsimshian Native Americans in British Columbia upon European contact and the ensuing epidemic (57%). Germany lost 15% of its population in the rather politically motivated WWI, if a pandemic disrupted food and other material supply chains and triggers wars for survival how many more might die? Meanwhile despite intermarrying with Europeans Native American populations still have lower genetic diversity compared to others. There isn’t any problem at the moment but what about 10,000 years from now? Perhaps there wouldn’t be such issues in real life for Native Americans via further intermarrying, but our scenario has humans/an intelligent species on its own with no outlet for an increase in genetic diversity.

As you say, scary stuff.

*Just using them as an example but this could apply to any intelligent interstellar species.

Inbreeding is caused by an very limited gene pool, not something who is much of an overall problem if you are an interstellar empire. 

The Native Americans was hit by an group of diseases: all the ones who had came or changed significant in basically the rest of the world since their last contact before the end of the ice age as in over 10.000 years. 
Result was as you say that most died, this happened multiple times on contact with peoples who had been isolated for an long time. Native Australian might be harder hit as population was smaller. 

Now this is not something I expect will come up again unless an colony has been out of contact with the main civilization for a long time and it will just hit the colony. 
But the will have much better medicine than us and space is very good for quarantine. Not an extinction event. Even if faster than light travel is common you will have large space stations. 

Some alien kills you off in an war of extinction is one way but that would be hard. 
Cosmic events are more likely, if you have colonized say 5 stars within 10 lightyear an supernova and similar would be bad news.  
Merging of two neutron star is more energic.  A black hole eating an massive star?  In short events who are lethal over many lightyears. 

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A swatted cockroach on the floor is a whole Universe for the bacteria spreading inside.

It's amazing, amusing, kind, and beautiful.
It gives all elements necessary for life, it gives home, it's full of mysteries, galactic arms (six legs and a pair of antennas), recurring structures, strange voids and walls.

And look at those two globular clusters consisting of thousands of lenses.
They are unbearably perfect themselves!
And even more, the ancient travellers tell us that if you can reach the center of such cluster, you can see thousand times farther through these lenses, and see strange moving pictures beyond the Universe limits.
Sometimes even captions in strange unknown letters like "Made in China. 9.5 US".

Nobody knows how did this beautiful world appear, but the scientists believe that there was a Big Bang! a thousand of generations ago.

Remember this watching the Laniakeia.

***

1 hour ago, magnemoe said:

Some alien kills you off in an war of extinction is one way but that would be hard. 
Cosmic events are more likely, if you have colonized say 5 stars within 10 lightyear an supernova and similar would be bad news.  
Merging of two neutron star is more energic.  A black hole eating an massive star?  In short events who are lethal over many lightyears. 

A pack of strangelets thrown into the closest pulsar to spread them around.

A modulated supernova explosion of the opponent neighboring blue giant.

Awaken Cthulhu or another form of destructive solipsism.

A multiverse where all of them are left on the alternative branch of existence.

Edited by kerbiloid
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If you can travel between the stars, killing off a planet is child's play. You simply don't flip&burn halfway through. Bye bye planet. And that's not even considering biological or chemical methods, which presumably would be far in advance of ours for a star faring civilization. Also consider time span, we managed to make our planet unlivable in a few hundred years, and we weren't even trying. For an interstellar war time scales would be much greater than a planetary war, so a few hundred years to mess up a planet's atmosphere wouldn't seem that big of an investment.

A supernova might seem dangerous but you only need to be around 50 light year away (at current estimates) to survive it, assuming an earth-like magnetic field and atmosphere. There's only going to be a very small window for a star faring civilization where they are interstellar, but haven't spread beyond 50 light years from their homeworld yet. If that window will exist at all, it's not unlikely there is no colonizable target within 50 light years from your home world. And they would see it coming millions of years ahead, plenty of time to vacate the premises.

No, I'm pretty sure there is no known localized cosmic event that would wipe out an interstellar civilization. A blazar jet might kill over longer distances than a supernova but is highly directional, it will only hit some of your star systems. And again, this would be predictable far in advance if it was going to happen close enough to kill you. It's really going to take an active agent to get it done.

Well, maybe there is one localized cosmic event that could do it. If we assume interstellar travel is limited to the home galaxy because intergalactic distances are simply too great, your galaxy could run out of material to form new stars. Old stars would die and you'd have nowhere to run to. It's a long trip to the next squashed cockroach.

 

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1 hour ago, Beamer said:

If you can travel between the stars, killing off a planet is child's play. You simply don't flip&burn halfway through. Bye bye planet. And that's not even considering biological or chemical methods, which presumably would be far in advance of ours for a star faring civilization. Also consider time span, we managed to make our planet unlivable in a few hundred years, and we weren't even trying. For an interstellar war time scales would be much greater than a planetary war, so a few hundred years to mess up a planet's atmosphere wouldn't seem that big of an investment.

A supernova might seem dangerous but you only need to be around 50 light year away (at current estimates) to survive it, assuming an earth-like magnetic field and atmosphere. There's only going to be a very small window for a star faring civilization where they are interstellar, but haven't spread beyond 50 light years from their homeworld yet. If that window will exist at all, it's not unlikely there is no colonizable target within 50 light years from your home world. And they would see it coming millions of years ahead, plenty of time to vacate the premises.

No, I'm pretty sure there is no known localized cosmic event that would wipe out an interstellar civilization. A blazar jet might kill over longer distances than a supernova but is highly directional, it will only hit some of your star systems. And again, this would be predictable far in advance if it was going to happen close enough to kill you. It's really going to take an active agent to get it done.

Well, maybe there is one localized cosmic event that could do it. If we assume interstellar travel is limited to the home galaxy because intergalactic distances are simply too great, your galaxy could run out of material to form new stars. Old stars would die and you'd have nowhere to run to. It's a long trip to the next squashed cockroach.

Using an starship for this has some downsides like its very obvious if some point an telescope towards the star. Second you will be limited in your max velocity to 20-30% of lightspeed unless you  use laser pumped solar sails who will be even more obvious, as you trust for over a year an survey will likely catch it. And remember you are not at .99 c but .3-.6 something so you will need something huge to do planet killing damage. So very obvious and pretty easy to intercept. Now you could make it harder dropping stealthy cool slugs hitting an planet like an shotgun shell. 
But I could just intercept it with an solar sail and they are not stealthy anymore :) 

More so if you are interstellar you will have lots of people living in space everywhere from Mercury orbit solar farms powering the pusher lasers to the belt, most of the industry will be in space to, killing the planet will just make them very liquided up and can use all the resources used to  provide heavy industry to the planet to military use. 
So you build the robots who build the robots who build the dyson swarm who power your weapon systems. 

Yes its some proof of aliens you don't want to see, the stars going out as we watch is one. 
Now if it happens over hundreds of years its not as worrying, but in decades and they are mobilizing hard. 
http://freefall.purrsia.com/ff1200/fv01163.htm

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1 hour ago, magnemoe said:

Using an starship for this has some downsides like its very obvious if some point an telescope towards the star. Second you will be limited in your max velocity to 20-30% of lightspeed unless you  use laser pumped solar sails who will be even more obvious, as you trust for over a year an survey will likely catch it.

Light sails (or anything else we have cooked up so far that isn't entirely theoretical) are not going to build an 'interstellar civilization'. Although technically you could claim a species is interstellar as soon as they colonize their second star, that does not quite make it a civilization yet. I'm thinking Kardashev type 3 or close to it here, which is pretty much where you'd have to be to be considered an interstellar civilization to me. After all the concept of a 'civilization' implies that you have some sort of organization that ties all these stars together under a single (or shared) authority, just letting some seeds blow along on the wind isn't quite enough. And then to kill all of that, well that would probably require an even higher level of advancement, right?

At that point, you don't stop at 0.2-0.3 c, you just power prograde all the way and how fast you end up going depends on how far away it is and how big a mass you're pushing. Still, assuming that the people on the receiving end are at a similarly high level of tech from our point of view, I certainly concede they might be able to detect it before it hit. Stopping it is another matter altogether though. And of course you don't use a 'star ship' for this, you just strap a tug to an asteroid or moonlet, no need to waste refined metals when any old mass will do.

People living in space are a good point though (although depending on the layout of the local system they might have to be extremely lucky to survive the shattering of a planet). Still there are plenty of options for that, a 'shotgun blast' as you mentioned could do some damage, or you might be able to mess with their star and swamp the system with radiation. At the K-III scale the more frightening options are probably the ones we couldn't even imagine yet, just like our iron age ancestors couldn't possibly have imagined all the inventive ways their descendants would develop to kill one another.

I don't pretend I can predict what our far removed descendants or a sufficiently advanced alien race could do (other than that, as good old Clarke would say, it would be indistinguishable from magic to us), I am just convinced that that's what it would take to make an interstellar civilization go extinct. Natural causes just aren't that far reaching on the galactic scale. It would require some form of agency to get to all of them.

 

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Meanwhile somewhere of space, a civilization that has developed beyond our imagination, who can spy on our internet:

image.png

My guess is that when a civilization is advanced enough to colonize an alien planet, unless the virus or whatever in the place it colonizes is strong enough, incredibly strong, then only a particularly bloody war between the civilization itself or a civilization similar to it would make extinction a possibility.

Edited by steve9728
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Posted (edited)

Everyone is saying war, because natural causes can’t do anything. But, what is they die out to natural causes we haven’t discovered yet? What if that’s the great filter? You can make it interstellar, but that unnamed phenomenon is what’d kill you. Quite literally, there’s a whole universe of possibilities. 

Edited by Kerbalsaurus
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https://www.scientificamerican.com/article/scientists-spot-the-biggest-known-explosion-in-the-universe/#:~:text=The energy released by the,the cluster MS 0735.6%2B7421.

Quote

"In some ways, this blast is similar to how the eruption of Mt. St. Helens in 1980 ripped off the top of the mountain," study lead author Simona Giacintucci, of the Naval Research Laboratory in Washington, D.C., said in a statement. "A key difference is that you could fit 15 Milky Way galaxies in a row into the crater this eruption punched into the cluster’s hot gas."

The explosion occurred in the Ophiuchus cluster, which lies about 390 million light-years from Earth. Giacintucci and her colleagues think the source was a supermassive black hole in one of the cluster’s constituent galaxies—specifically, jets of radiation and material spewing from the light-gobbling monster, which are powered by inflowing gas and dust.

 

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4 hours ago, Kerbalsaurus said:

Everyone is saying war, because natural causes can’t do anything. But, what is they die out to natural causes we haven’t discovered yet? What if that’s the great filter? You can make it interstellar, but that unnamed phenomenon is what’d kill you. Quite literally, there’s a whole universe of possibilities. 

I don’t think this is likely in *the physical world*, because there would be past evidence of it. If there was something out there, even if we didn’t know what caused it we would see signs of it.

I would be more concerned about biological and sociological factors. What happens when a technologically advanced species marks 10,000 years? Or 1,000,000 years? Are intelligent species capable of surviving for that long, or will some behavioral or other mental effect begin to take hold after time and doom the species?

One somewhat unrelated example of this is the possibility that no intelligent species whatsoever is fit for interstellar space travel. Sooner or later fighting breaks out on the ship just as it does sooner or later on the home planet and it is destroyed before it can reach the destination.

On the other hand, rats or mice with robotic caretakers would have no problems because their behavior is well understood and they don’t freak out like humans can.

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4 hours ago, Kerbalsaurus said:

But, what is they die out to natural causes we haven’t discovered yet? What if that’s the great filter? You can make it interstellar, but that unnamed phenomenon is what’d kill you. Quite literally, there’s a whole universe of possibilities. 

Gamma Ray Burst. Cook'em all!

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Once we pass on and our consciousness is no longer bound to this universe's physics then we can leave the black hole our known universe is in then all answers will come .

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Ah, I suddenly remembered a novel: The Wandering Earth. It is by the same author as the novel Three Body. If I remember correctly, I think I've seen both of them in English version of these novel in the UK.

It's okay if you can't find the novel, there is a film adaptation of the novel. And its available on Netflix with English subtitles:D

Apart from war and pestilence, if this colonization is the "last hope" for this civilization, there are still many things that can destroy them all at once on the way.

Edited by steve9728
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On 10/3/2022 at 8:00 PM, kerbiloid said:

Wow that might be the biggest bang since the big one. It sounds like it was powerful enough to destroy whole galaxies. Even a galaxy spanning civilization may not be entirely safe.

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1 hour ago, tomf said:

the biggest bang since the big one

I'll borrow this phrase.

Anyway, seems like natural causes can wipe out galaxies. Well, I hope it's natural, because the alternative is terrifying.

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