How can a star-faring race get extinct?

[frogcurry]

- Skynet style annihilation.
- Technological singularity resulting in ceasation of biological existence.
- Out of control technology, i.e. nanotechnology which either purposefully or accidentally begins functioning in a bad way, say disassembling all DNA it encounters.

[Rye]

They could become extinct by settling down with some post scarcity technology that looks after them and then eventually just genetically diverging from the race that initially invented the technology. Imagine if we spread about the universe with replicators and teleporters and the like, then after ten million years, had long since stopped seeing the point in anything but total dependence on the technology. Then perhaps the power source failed.

Perhaps a species could suffer genetic damage that led to it becoming more stupid over time and eventually they became just another animal on the planets or orbitals they'd seeded. Perhaps the technology they depended on got ideas of its own on how to best care for them and gradually engineered them to be more compliant and simplistic.

[Lord of the Abyss]

Perhaps a species could suffer genetic damage that led to it becoming more stupid over time and eventually they became just another animal on the planets or orbitals they'd seeded. Perhaps the technology they depended on got ideas of its own on how to best care for them and gradually engineered them to be more compliant and simplistic.

I recall two stories like that offhand. An old one called "something Orchid" ( only recall part of the title ), where the race in question became more and more self indulgent, eventually turning into wireheads dependent on direct stimulation of the pleasure center, and eventually devolved onto what amounted to a pleasure center and some support organs. Kept alive by their sentient machines the whole time.

Another is The Hunted Earth duology, where a race sent seeder probes with it's DNA and computers programmed to adjust the race's DNA to match the planet. The was some sort of error, and the computers turned the "colonists" it grew into extensions of itself. The computers then set out to do what they were designed to do, produce more colonies. The result was a "Von Neumann Cyborg Cluster", a part organic, part mechanical "race" that had little in common with the originals. And it killed off it's creators along with just about everybody else; it's the solution to the Fermi Paradox. We hear no aliens because they all got eaten.

Other means of extinction :

From Acts of Conscience, superweapons that can kill instananeously over intergalactic distances. The ancients had a cold war, that turned into a hot war, and * BOOM *, in a few seconds nearly every sentient species in the universe is killed.

From the Draco Tavern universe, a species investigates the afterlife, has a breakthough - and everyone kills themselves. Anyone who studies what they are doing too much also kill themselves. Eventually the records are destroyed.

I've read several books where the galactic core sterilizes large swathes of space, or the whole galaxy.

[CaptainChewbacca]

Actually, they last from milliseconds to a few minutes, and they do not "devastate anything in its path." Earth was hit at least once, and it did not even stelizie the planet (although it did cause a mass extinction event, probably due to damage to the ozone layer). GRBs are not some uber cosmic ray of doom.

Have a very nice day.
-fgalkin

The 'front' of a GRB lasts from miliseconds to seconds, but the 'tail' of a GRB can take several weeks to pass a given body, which is why GRBs are often observed over a period of days or even months. I believe the longest recorded was around 78 days. The GRB which hit earth originated from several thousand light-years away, but a GRB from 1000 Ly or less will definitely devastate a planet.

Sikon, a GRB is not solely caused by neutron star collision, it can also be the result of a metal-poor collapsar going supernova.

[fnord]

What about the old classic of internecine(?) civil war? Self-annihilation writ very large.

In the Traveller setting, one species (the Ancients) pulled it off, and another (Humaniti) gave it a damn good shake.

[Junghalli]

Killing an interstellar civilization would probably be a lot easier than killing an interstellar species. SF tends to use the two terms as synonymous, but they really aren't.

An organized interstellar civilization falling isn't particularly difficult to imagine - it could fall prey to the same things that brought down dead civilizations on Earth. It could fall to external enemies, disintegrate due to internal conflicts, just sort of fall apart under its own weight like the early Caliphate did, or some combination of the above.

Wiping out the entire species is a much more challenging proposition. Most of the above calamities could be expected to leave survivors. The most straightforward way to do it would be to have the species be completely wiped out by an external enemy that was for some reason determined to kill every last one of them. Alternatively, you could go with a fast-spreading plague with a long incubation period and a 100% mortality rate, such as happened to the Fourth Imperium in the Empire From the Ashes series.

Of course, the question is, for story purposes is it really necessary that the entire species die? You could have the ancient civilization leave behind survivors, but they all got knocked back into the Middle Ages when the civilization collapsed. The civilization would be gone, in the same way the Classical Greeks are gone. Depending on how long ago it was and how bad the collapse was the survivors could easily have lost all memory of it, save for vague myths.

This would also answer the question of "if they got wiped out, what happened to the guys who wiped them out?" Species A wiped out Species B, then Species A's civilization collapsed later.

[Junghalli]

Would it be a reasonable assumptions that the race that could build a ring the size of a small planet's fucking orbit could have some basic knowledge and technology for medicine?

It's also rather stupid, because actually trying to keep any disease causing bacteria off a world would be pretty close to impossible, since every normal person has billions of parasitic and symbiotic microbes living on and in him. Any one of them has the potential to become a disease with the odd mutation, and there are lots of them that would be diseases if the person's immune system wasn't keeping them in check.

As I remember the whole thing was just random hypothesizing by Louis Wu, before he found out what actually happened (it was a bacteria that ate superconductors).

[Oni Koneko Damien]

But, if we are realistic for a second, how could this happen? How would it be possible for a race to die out altogether and leave entire solar systems empty?

One possibility is just the general degeneration of culture and technology. Perhaps at one point the race had galaxy-dominating power, but then it went past its zenith. Things degraded, records weren't kept as well as they should as corruption grows, eventually technologies are lost. Perhaps at some point they lose their FTL capabilities and lack the records and technology to rebuild.

Granted, actually killing off everything by this method is highly unlikely, an interstellar civilization is statistically much more likely to have certain pockets that don't degrade as much as everything else. And if FTL is generally lost, survival would probably become even more likely as however many thousands of now isolated systems each go off on their own, essentially forming thousands of individual cultures, each with some chance of survival.

H.P. Lovecraft's Elder Things are a good example of the cultural degradation. They came to earth about two billion years or so ago, inadvertently created life on earth from the random bits of protoplasm that fell off their slave-race, and established a planet-dominating civilization. Over the eons, a few other races come in, they have a few nasty wars, and eventually settle for owning the oceans and the southern hemisphere minus Australia.

After that, things just went downhill for them. Their culture degraded, they lost their FTL technology, and as the climate cooled, they were forced into a smaller and smaller area. When the Shoggoths finally rose against them the second time, they were wiped out, though all their ruins remained.

Would it be a reasonable assumptions that the race that could build a ring the size of a small planet's fucking orbit could have some basic knowledge and technology for medicine?

Medicine, maybe, but not necessarily against certain disease-causing agents. If a species has little to no contact with, say, bacteria, it 1) Won't evolve any biological counters to it, and 2) develop any technological counters to it because it's not even a known possibility to them, much less a worrisome threat. Aliens who have no experience whatsoever with bacteria wouldn't develop any defense against them the same way humans haven't developed any defense against...as, gamma-ray spitting, parasitic mind-leeches.

[eyl]

Killing an interstellar civilization would probably be a lot easier than killing an interstellar species. SF tends to use the two terms as synonymous, but they really aren't.

An organized interstellar civilization falling isn't particularly difficult to imagine - it could fall prey to the same things that brought down dead civilizations on Earth. It could fall to external enemies, disintegrate due to internal conflicts, just sort of fall apart under its own weight like the early Caliphate did, or some combination of the above.

Wiping out the entire species is a much more challenging proposition. Most of the above calamities could be expected to leave survivors. The most straightforward way to do it would be to have the species be completely wiped out by an external enemy that was for some reason determined to kill every last one of them. Alternatively, you could go with a fast-spreading plague with a long incubation period and a 100% mortality rate, such as happened to the Fourth Imperium in the Empire From the Ashes series.

Of course, the question is, for story purposes is it really necessary that the entire species die? You could have the ancient civilization leave behind survivors, but they all got knocked back into the Middle Ages when the civilization collapsed. The civilization would be gone, in the same way the Classical Greeks are gone. Depending on how long ago it was and how bad the collapse was the survivors could easily have lost all memory of it, save for vague myths.

This would also answer the question of "if they got wiped out, what happened to the guys who wiped them out?" Species A wiped out Species B, then Species A's civilization collapsed later.

Species extinction could also be a two-step event, with the civilization's fall occuring as you described it, leaving technologically retarded survivors, and then some centuries later, those survivors dying out because of other unconnected events (e.g. plague, civil war) which their original civilization could have easily dealt with (such a scenario might also imply that civilizations surviving to starfaring status is a fairly rare event).

[Admiral Valdemar]

You could easily have a species that has fractured into groups that vary in their scale of civilisation too. For the Amarantin in Revelation Space, a religious sect was, unsurprisingly, a powerful Luddite movement that caused a scientific, more progressive splinter group to breakaway and form their own nation. In time, the two groups diverged to the point that one was toying with genetic engineering and rocket science, while the other was building ziggurats and performing sacrificial ceremonies.

Eventually, the atheistic sub-species, by this point, left the planet, but in their error, alerted the Inhibitors to their new-found ability to leave their planet and solar system. That resulted in the religious sub-species, who as far as they were concerned now saw the scientific version of their race as gods, being wiped out by an induced solar flare. The space-farers then went into hiding, not so much extinction, though they couldn't settle and form society again and remained on the run or hiding.

Incidentally, apart from flares, the Inhibitors also produced GRBs and the like by shifting neutron stars to collide and other such stellar engineering. It won't kill everyone they want unless still stuck in a select area in their solar system (which goes against their mission to stop only extra-solar flight capable species), but it does tend to deal with those that haven't considered such events a threat for the reasons Sikon stated. The next step would be orbital bombardment or, in extreme cases, killing their star (and if massove enough to be capable, maybe a supernova).

A species on the run, without a home world or any major base of operations to sustain itself indefinitely, is far easier prey to add to the extinction list than one that isn't.

[Ryan Thunder]

In Ringworld, by Larry Niven, didn't the Engineers eventually succumb to the common flu? They built the Ringworld without any form of disease, so their immune systems atrophied. One of their ships brought back some plague from a world it visited, and with no defense...

I thought they turned their worlds into junkyards after building the Rings, then the junkyards inadvertently bred some organism that ate superconductors. Then it stowed away on board ships and the ships spread it around. So it destroyed their technology and they reverted to a pre-industrial state.

Least, that's what I remember from the original book...

[Junghalli]

Species extinction could also be a two-step event, with the civilization's fall occuring as you described it, leaving technologically retarded survivors, and then some centuries later, those survivors dying out because of other unconnected events (e.g. plague, civil war) which their original civilization could have easily dealt with (such a scenario might also imply that civilizations surviving to starfaring status is a fairly rare event).

The question there is, if they've lost FTL, what could reach all their worlds and kill them all? A plague couldn't spread beyond one planet, ditto for a civil war (which would be expected to leave survivors anyway). I suppose an external enemy is one possibility. Another might be a gamma ray burst.

Alternately, it could be that once they lost FTL most of the colonies died. Once an FTL civilization collapses a lot of colonies would probably die. Any colony dependent on the homeworld for resources vital to survival would be totally fucked. Most colonies that regressed below agricultural level would probably be fucked; alien biochemistries make it rather unlikely that hunter-gatherers could survive on a planet they didn't originate on (or that hadn't been extensively seeded with their kind of life).

I thought they turned their worlds into junkyards after building the Rings, then the junkyards inadvertently bred some organism that ate superconductors. Then it stowed away on board ships and the ships spread it around. So it destroyed their technology and they reverted to a pre-industrial state.

You got it about right. Except that it was revealed in a later book that the bacteria had actually been deliberately created and introduced by the Puppeteers.

[AMX]

First-world countries tend to have negative population growth.
Any species exhibiting the same tendency, and unwilling to maintain their numbers artificially, would eventually dwindle away.

[eyl]

The question there is, if they've lost FTL, what could reach all their worlds and kill them all? A plague couldn't spread beyond one planet, ditto for a civil war (which would be expected to leave survivors anyway). I suppose an external enemy is one possibility. Another might be a gamma ray burst.

And it could be both. Over time, all the worlds may be devastated by different and unconnected events. Or, as you pointed out, overreliance on technology or trade for vital resources can destroy a lot of them.

[Junghalli]

First-world countries tend to have negative population growth.
Any species exhibiting the same tendency, and unwilling to maintain their numbers artificially, would eventually dwindle away.

IIRC they have negative population growth because they're basically stabilizing after a population explosion. And it's not all that hard to encourage people to have babies; the instinct to reproduce is pretty strong. Granted we're talking about aliens, but the same should be true for them.

[AMX]

First-world countries tend to have negative population growth.
Any species exhibiting the same tendency, and unwilling to maintain their numbers artificially, would eventually dwindle away.

IIRC they have negative population growth because they're basically stabilizing after a population explosion.

I seem to remember differently.

And it's not all that hard to encourage people to have babies; the instinct to reproduce is pretty strong.

Actually, it's easy to encourage people to have sex; producing offspring is a slightly different matter.

[Genii Lodus]

First-world countries tend to have negative population growth.
Any species exhibiting the same tendency, and unwilling to maintain their numbers artificially, would eventually dwindle away.

IIRC they have negative population growth because they're basically stabilizing after a population explosion. And it's not all that hard to encourage people to have babies; the instinct to reproduce is pretty strong. Granted we're talking about aliens, but the same should be true for them.

I would expect most FTL-capable species to have access to sufficiently advanced life-extension and medical technologies giving a reduced death rate which reduces the birth rate needed to maintain a stable population. This would stave off democide.

• - Disease -I'm unconvinced that any FTL-capable interstellar civilisation will have advanced to that point but still remain vulnerable to disease to the extent that it would collapse because of it. Even in a mono-species civilisation you're not going to get collapse because of a disease let alone extinction.
  - Natural Disaster/External Aggressor - If FTL-technology is sufficiently available I think it would be close to impossible for anything to wipe out an entire species in a short period. It's a big universe and there's a lot of places to hide if someone's hunting you. If FTL scanning/communication is available it would be possible to outrun any natural event. That said if the civilisation(s) a species is part of is effectively destroyed to the degree of the 12 Colonies of Kobol the extinction of the species would follow in a few generations. Depends on what a viable breeding population would be and whether the survivors have the infrastructure to resettle.
  - Ascending/Singularity - The civilisation might go but not all the species would. It would seem unlikely to me that every member of a civilisation reaching singularity/whatever would partake as there's always going to be some troglodytes with their primitive attachment to biological existence. Coercion is possible but unlikely given the above assumed ease of hiding.
  - Technological disaster - maybe, it depends on the laws of physics in this FTL universe as to what kinds of freaky stuff is possible.
  - Internal Conflict - don't think there's ever been a civil war fought which left no survivors. Again civilisation might collapse but it's unlikely the species would be extinct.

In summary I think any species robust able to achieve an interstellar FTL civilisation will be robust enough to avoid their (quick) extinction. Long-term survival is not so assured and depends on the number and state of the survivors.[/b]

[Teleros]

Had a similar problem trying to wipe out a couple of civilisations in my own sci-fi setting. Pretty much had to resort to a nice big war they lose horribly, plus a lack of outside help - everything else seemed / seems avoidable to some degree.

[Ender]

In Ringworld, by Larry Niven, didn't the Engineers eventually succumb to the common flu? They built the Ringworld without any form of disease, so their immune systems atrophied. One of their ships brought back some plague from a world it visited, and with no defense...

not quite - a ship brought back a fungus that had evolved on one of their old city planets, and it ate the superconducting material they used. Once their tech started failing they were screwed because they were in a hydraulic situation and needed it to stay alive. And the size of ringworld worked against them - without their tech they were limited in how fast they could warn others and work together to find a solution, and the fungus spread faster then they could pass along word.

[Ender]

Without FTL travel then standing too close to a supernova could do it, if the star in question is big enough it could take out everyone for more than a hundred lightyears all around it (if I remember correctly).

Once you've got FTL travel effective enough for a civilisation to move out of the way in time that becomes less likely. You could have a war where the enemy blows up all their victims colonies then releases a plague on the homeworld, or releases a plague onto all of their planets. Most effective would be the type where, as someone already suggested, you don't know it exists until it's too late. There's also weird esoteric quasi-sci-fi things like mass telepathy induced suicide.

No, even with FTL you will still be screwed - you will have the bottleneck of how fast you can move the population off the planet. Iron Sunrise covers this pretty well, though R-bombs are the threat, not a supernova.


Honestly, the best explanation is that they just kept evolving and the old original species went extinct. Though on that time frame you won't have artifacts left behind, but you wouldn't have that in any realistic scenario anyways.

[Shrykull]

I remember in reading Michio Kaku's hyperspace, a way for a type 2 civilization in real life to die would be a nearby supernova (say within a 100 light years) this is what happened to the T'kon empire (though the non-canon Q continuum novels tell the story of how)

Though, yes I'd imagine if they were exterminated by another race, that race was annex their planets, not leave them there.

Also, in sci-fi, the TNG episode The Survivors, the dowd destroys the entire husnock race with a thought.

[Darth Ruinus]

I remember in reading Michio Kaku's hyperspace, a way for a type 2 civilization in real life to die would be a nearby supernova (say within a 100 light years) this is what happened to the T'kon empire (though the non-canon Q continuum novels tell the story of how)

Though, yes I'd imagine if they were exterminated by another race, that race was annex their planets, not leave them there.

Also, in sci-fi, the TNG episode The Survivors, the dowd destroys the entire husnock race with a thought.

Not to go off topic, but, how are we sure that he killed all of them?

[Sikon]

Without FTL travel then standing too close to a supernova could do it, if the star in question is big enough it could take out everyone for more than a hundred lightyears all around it (if I remember correctly).

Once you've got FTL travel effective enough for a civilisation to move out of the way in time that becomes less likely. You could have a war where the enemy blows up all their victims colonies then releases a plague on the homeworld, or releases a plague onto all of their planets. Most effective would be the type where, as someone already suggested, you don't know it exists until it's too late. There's also weird esoteric quasi-sci-fi things like mass telepathy induced suicide.

No, even with FTL you will still be screwed - you will have the bottleneck of how fast you can move the population off the planet. Iron Sunrise covers this pretty well, though R-bombs are the threat, not a supernova.

A star at risk for a near-future supernova may be identified likely millions of years before supernova. Whether with STL or imaginary FTL transport, a technological civilization operates on orders of magnitude faster time scales than geological or rather astronomical timeframes like the typical remaining lifespan of stars (millions to billions of years). If it is expansionary, it will tend to expand orders of magnitude beyond the destruction radius of an individual supernova in a tiny portion of the first million years of its existence.

Keep in mind that supernova are rare events. While a supernova occurs every few decades or so somewhere in the galaxy with its large fraction of a trillion stars, the chance of a truly nearby supernova in a given century or even a given million-year period is tiny.