What type of natural or artificial disaster could devastate a multi galactic civilization?

Question

There is an advanced civilization that spans multiple galaxies. The civilization has learned to tap every available source of energy within the volume that it has colonized. The civilization flourishes, expands, and advances in knowledge and technology for billions of years, before experiencing a disaster that is so devastating that it takes them more than 2 billion years for them to fully recover.

What type of natural or artificial disaster could cause such devastation to a multi galactic civilization?

Answer 1

Ennui.

The disaster is millions of years in the making, but for a civilization that has lived billions, it's as nothing. People have conquered every challenge available. They turn inward. Population growth is negative because nobody cares to do anything about it. War spreads as a means of entertainment. Even that grows old and the survivors give up. They carry on their extraordinarily-long lives in mechanistic fashion until literally dying of boredom. There is no joie de vivre.

The civilization dwindles to practically nothing. The remnants live bitter lives. They pass this condition on to the few children born to deviants who backslide. It is millions of years before one newborn deviant breaks the mold. She is the start of a new subculture that clings tenaciously to ambition. These youngsters spread slowly back amongst the stars. Over two billion years, they recolonise all the old worlds, relearn all the old tech, and displace all the old farts.

Answer 2

Computer virus

Any civilization close to or above K1 is going to be heavily automated. Your administrators are computers, your farmers, doctors and technicians are robots. Everything is networked for most efficient operations.

If a virus, or a bug takes out 10% of your infrastructure for couple of months you may experience total collapse of stargate/wormhole network, heavy disruption of energy production, etc.

Significant fraction of your population lives in megastructures that require huge amount of energy for life support or maybe even structural support. Disruption of energy production makes your people literally suffocate in their beds, and the cities physically collapse. Your databanks, communication arrays, and command centers get buried under kilometers or rubble for centuries.

50-90% of population is dead. The rest lives in isolated pockets, the civilisation collapses.

Answer 3

Reality rift.

My answer from this question: Speculative weapon of mass destruction

Someone in your civilization, possibly as an art project, starts unravelling God's stitches. The barriers between dimensions and alternate forms of reality get shaky and loose. Monsters, gods, different physics, strange weeds. Angels and bugs and angels with bugs and all of that. Stuff gets unpredictable, to say the least.

The artist is pretty stoked though.

Answer 4

Civil war of some kind is the usual answer. The enemy will have the same level of technology and access so being advanced or large does not protect.

The civil war could be ethnic. Many science fiction universes include past empires that end with a revolt by subject species. The rebels usually have less advanced technology and fewer resources but have the huge advantage of it not being their empire that gets wrecked by the conflict. This might feasibly lead to burned Earth tactics and genocide.

Rebellions by AI or artificial or artificially modified lifeforms are a common trope. AIs can make the advanced technology turn against its creators. This naturally leads to much of the infrastructure being destroyed and the population turning away from science and technology.

Artificial life is generally something that has insane adaptability and biological war forms. This typically has the horror aspect of being able to assimilate defeated enemies or civilians who get in the way. A variant of this is technological life that assimilates our hardware. A cyborg variant like the Borg from Star Trek is also possible. Such war will directly destroy thru assimilation much of population or hardware which will result large scale devastation. In effect the empire will get eaten from the inside.

A variant of this is religious or ideological collapse. An idea spreads among the population and makes it turn away from the empire, which then collapses. People might abandon physical existence for spiritual or virtual one. People might reject advanced technology. People might reject sentience itself. This type of conflict might be largely peaceful without any actual fighting. Or it might involve lots very intense fighting and brutality. In any case, the empire will go away and its works will be largely erased or hidden to avoid unfortunate accidents when somebody stumbles on the "pocket size supernova catalyzer" without knowing that the pushing the red button will destroy the entire solar system.

Answer 5

A multi-galactic civilization is pretty well impervious to any conceivable NATURAL disaster. Nothing short of the complete collapse of spacetime throughout the universe is going to have effects on that scale.

However.

Civilization is always built on social and technological structures that make it possible, and the easiest way to create the kind of chaos that you're talking about is to kick one of them over. Make your civilization completely dependent on a particular technological tool or process, and then have it stop working for some reason.

The best example of this I can think of offhand is from the Hyperion novels by Dan Simmons. In this case it's just a single-galaxy civilization, but the principle is the same. The civilization has spread and built its entire social and economic infrastructure on a technology that allows instant teleportation anywhere in the galaxy. It's so cheap and easy that nobody travels or moves goods any other way. It's been like this for so long that nobody CAN travel or move goods any other way. Then it stops working. All communication between planets and even cities is cut off. Nobody can move food.

It's not even that far Out There as far as Science Fiction is concerned. IN 1859 the Earth was hit with a massive solar flareenter link description here. This caused aurorae to be visible as far south as the tropics, and so bright that people in temperate latitudes could read by its light. Telegraph wires were collecting so much eccess current that they were starting fires.

A similar event occuring today would be MASSIVELY disruptive, because modern society is completely dependent on electricity and wireless communication. A solar event of this magnitude would knock out GPS and satellite communications entirely, potentially to the point of destroying the satellites themselves. Power grids worldwide would go down, potentially for months due to widespread damage to transformers. Distribution of food and fuel would be severely impacted. Depending on the time of year, loss of power would cause significant loss of life due to the sudden loss of the ability to heat homes. And that's not even taking into account the damage that humans might start doing themselves at that point just out of panic.

So, TLDR. Destroy your multi-galactic civilization with panic.

Answer 6

Collapse of the social order

There aren't many natural events that can affect multiple galaxies, but a civilisation that size will struggle with one of two key aspects. It's either centralised, in which case a little corruption at the heart will go a long way to causing a breakdown or decentralised, in which case the regions may feel disconnected from the civilisation as a whole.

Either way the peripheries may err towards claiming independence after some real or perceived slight from central government and the whole system breaks down.

Stagnation with lack of budget to expand to new galaxies

They've tapped every energy source and they're using it all, but the push to expand to a new galaxy to get more resources is greater than the budget the politicians are willing or able to put into it, trapping the civilisation under current energy constraints and causing inevitable collapse as consumption continues to increase.

Note that I don't have much faith in politicians, incompetence and failure to plan for the future over surviving the next election cycle are the most likely causes for collapse.

Answer 7

A variation in the value of one or more fundamental constants

The universe is defined by a set of fundamental constants (the best known ones being the speed of light, the gravitational constant and the Planck constant). If the value of one of them was even slightly different, the life as we know couldn't exist.

The problem is that the idea that these values are immutable is just an assumption. In truth, nothing assures us that their values are really constant: they could be different in some zones of the universe, or could change through the eons.

So, in case the gravitational constant or the speed of light abruptly changed, it would have unpredictable effects on everything in the universe, included the multigalactic empire: for instance, if the gravity abruptly became too weak to keep the planets together, the empire could cease to exist in less than one femtosecond (together with all life in the universe).
Other changes in the constant values would have very disruptive effects altogether, for instance rendering impossible all the biochemistry, or (in case of a more limited impact) rendering useless all the exotic technologies that allow the empire to exist.

Answer 8

Understand that we would need very hypothetical science to make it work, but here are a couple of idea:

1. Scientists create a baby universe in a lab, but rather than expanding in a separate universe, it expands inside our own, engulfing or pushing aside stars and galaxies as it expands at the speed of light (or possibly faster). After a billion years or so, this new universe reaches its apex and begins to collapse again, and after another billion years or so, it is gone. As it collapses, it draws galaxies into the void it leaves, and the civilization may start over.
2. The civilization is based on a network of wormholes, which collapses, suddenly or fairly quickly. All planets are left on their own, with the closest being able to maintain some contact with slower-than-light communication ad possibly spaceships. After two billion years, a new network of wormholes is born, and intergalactic civilization can start again. Possibly, some smaller, pocket wormhole networks survived the collapse, and these start growing slowly and ultimately reconnect. John Scalzi's novel The Collapsing Empire deals with such a situation on a much smaller scale.

Answer 9

One amazing example of an interstellar civilization brought to it's knees by natural causes is in the transformers lore. It was called the Age of Rust, and it was devastating. It was an incredibly virulent and incurable plague that spread rapidly and almost lead to the collapse, only being stopped by complete quarantine. Have something like this, but with a longer incubation period. Many people will die, and those that don't will close themselves off completely. While you can read more about it in the linked wiki, it is a really great chapter in a book called Covenant of Primus. While it involves robots in the book, you can easily transfer it to humans.

It could go something like this.

From a far distant world, your homeworld gets a distress call. Garbled by the distance, they can only hear short snippets, but those that they hear are disturbing. Horrible... falling apart... close ports. Shaken, they issue orders to quarantine that planet, but it has only begun. Messages start pouring in. Refugees from infected planet coming in droves. The disease popping up seemingly at random throughout the systems. And all through it, the terrifying march of an incurable disease. It spreads through touch and air and water. It lies quiet, asymptomatic for days. And then all at once it starts to steadily turn the infected person into virulent spores. They dissolve into a fine dust, bit by bit. And the plague is coming. The next day, the infected number in the hundreds. The next, the tens of thousands. High command order to close off all planets, ships, but those on infected worlds are already fleeing. They desperately try to make it through blockades, and the whole system watches in sickened disbelief as battlecruisers are forced to fire on unprotected civilian ships. And it isn't working. And so the people of the homeworld rise to a civilization with trillions of people infected, and on the news they hear the impossible. All across the galaxies spaceflight has stopped, as a small bomb inserted in every engine capable of spaceflight ever made detonates. The stargates, the only thing capable of bridging the gap between the galaxies are destroyed and the plans burned. And now all they can do is watch. Watch and realize that they are the only planet left unscathed. Watch as all that they have achieved over billions of years, the progress of their species... turns to dust.

Thanks for reading, hope you enjoyed the OC.

Answer 10

Ever played a video game in God mode? You would probably stop after a few hours cause it's just NOT FUN anymore.

A society with BILLIONS of years worth of technological advance would be a disease to itself. It would know everything, experienced everything and be almost God-like. There's no more challenges. You know how people hunt for fun instead of for food now? Why? Because we crave the challenge (I am not defending trophy hunting, just stating why) and not just the result. So in a society where everything is easily achieved, people will get bored and tired of living. Eventually, a splinter group will understand that only way to be happy again is to destroy everything they built. They basically destroy all the technology until it goes back to a time where living is a challenge and "fun".

Answer 11

Didn't yet see aliens which are on a similar level and which may be strong enough to cause a lot of troubles.

Also, what would happen if the species overused a resource and it eventually became unavailable? Fissionable material, an element used (up) in some technology, stellar objects suitable for slingshotting becoming unstable through too many space ships, and so on.

If the galaxies were very close together and there were a few very large black holes in the center of that cluster, an unexpected collision might be able to damage the technology they use. Which might cause a chain reaction of resource issues, resource fights, civil war and collapse.