What do you think the Great Filter is?

The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. The Great Filter is one possible resolution of the Fermi paradox.

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

The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. As a 2015 article put it, "If life is so easy, someone from somewhere must have come calling by now."

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

Personally I think it's photosynthesis. Life itself developed and spread but photosynthesis started an inevitable chain of ever-greater and more-efficient life. I think a random chain of mutations that turns carbon-based proto-life into something that can harvest light energy is wildly unlikely, even after the wildly unlikely event of life beginning in the first place.

I have no data to back that up, just a guess.

Chainweasel , (edited )

I think that the great filter/fermi paradox is a combination of two facts,

  1. Our entire radio output (the only example we have to go by) is pitiful compared to the sun, like a candle in front of a flood light, you'll only be able to see it so far before it's completely drowned out. After a few dozen light years our radio output is less than the margin of error of a stars detectable radio output.
  2. As a civilization advances it must reduce radio leakage. As data gets more important, it gets more important that you're not wasting energy moving it around. Narrow beamed radio transmission becomes the norm and even less radio signals escape the system than when radio was messy and overpowered.

They're not missing or gone, they've just moved beyond messy radio signals. Even we tightened up our radio emissions in a little over a century. Most of what we watch or listen to comes to us via fiber, cable, or short range transmissions like cell phone towers and Wi-Fi.

Unlimited ,

Probably too optimistic and unhinged, but maybe a species advanced enough for interstellar travel, building mega structures etc. are advanced enough to ascend to a higher plane of existence or alternate dimensions or whatever. Maybe there's some alternative to this reality that will be unlocked by advanced technology that made all advanced life prefer that, to here.

Cryophilia OP ,

That's a really neat idea I've never heard before. Like, maybe our entire universe is analogous to the ocean floor sea-vents that life arose out of. Cold, and dead, and boring, and difficult. And one day we'll discover how to ascend.

HaleHirsute ,

I also like this theory. In the Ian Banks Culture series civilizations that get advanced enough head off into the “sublime” they call it. Basically a higher level of existence. In my own more simple version, I’d figure VR and the biological/cyborg mix get so good the powerful can start living kind of forever, so they head for that substrate and don’t need big megastructures for anything, they just need computing power.

jballs ,
@jballs@sh.itjust.works avatar

Yeah, it seems very possible that at one point, civilization will turn inward instead of outward. Why go through the time and effort to colonize the stars when you can just create a cyber-utopia? If you're advanced enough, you could make it feel like an eternity while almost no time passes on the outside.

Sure, your planet might get destroyed by a cataclysmic event in the far future, but if you can make that feel like billions or trillions of years, who really cares?

Cryophilia OP ,

Honorable mention: we haven't detected alien probes, because intelligent alien societies haven't begun consuming the galaxy with exponential numbers of self-replicating robotic probes, because that's just a really bad idea:

Simple workarounds exist to avoid the over-replication scenario. Radio transmitters, or other means of wireless communication, could be used by probes programmed not to replicate beyond a certain density (such as five probes per cubic parsec) or arbitrary limit (such as ten million within one century), analogous to the Hayflick limit in cell reproduction. One problem with this defence against uncontrolled replication is that it would only require a single probe to malfunction and begin unrestricted reproduction for the entire approach to fail – essentially a technological cancer – unless each probe also has the ability to detect such malfunction in its neighbours and implements a seek and destroy protocol (which in turn could lead to probe-on-probe space wars if faulty probes first managed to multiply to high numbers before they were found by sound ones, which could then well have programming to replicate to matching numbers so as to manage the infestation).

grrgyle ,
@grrgyle@slrpnk.net avatar

Oh my god, that's such a stupid and simple way to kill a galaxy, but also what a great plot twist that would make in a story. Like the big reveal over why the galaxy has always been at war with itself. Exactly the kind of nihilism I'd expect from an Altered Carbon or its ilk.

Thanks for sharing!

Cryophilia OP ,

You might like the paperclip maximizer thought experiment

Also an excellent clicker style game called Universal Paperclips

grrgyle ,
@grrgyle@slrpnk.net avatar

Thanks I have heard of this kind of problem before, just not in an adversarial space war context, with like opposing forces

notabot ,

There's an easier and more reliable way to limit replication; don't hive them the means to create a small but essential part, and instead load the first probe woth many copies of it and have each replica take a set percentage.

For instance, have the probe able to replicate everything but its CPU, and just load up a rack of them on probe 0. Every time it replicates itself it passes half of its remaining stock to the replica and they both carry on from there.

CarbonIceDragon ,
@CarbonIceDragon@pawb.social avatar

My suspicion is that it's abiogenesis, but it's only a suspicion that I can't have any certainty of

NeptuneOrbit ,

Definitely the simplest answer and aligns so far with out observations.

Kyrgizion ,

Nah, I'm willing to bet there is actual physical life in our very own solar system (apart from all life on Earth, of course).
Europa's oceans for example have a decently high probability of hosting microbial life.

Of course, discovering primitive life all around us would be a bad sign the great filter is still ahead of us instead of behind us...

yyyesss ,

the internet. or some other mass communication methodology. we have developed it before we're responsible enough to have it. there are too many bad actors ready to take advantage of our innate biological tribalism. we'll kill ourselves before we reach very far into space.

Lupus ,

Erasmus of Rotterdam (1466-1536), Dutch Renaissance humanist:"To what corner of the world do they not fly, these swarms of new books?"

I think people were concerned about that kind of scenario since the invention of the printing press, if not the written word itself.
Not trying to dismiss the destructive potential the Internet can and will have in the future, just pointing out, that this kind of fear is not new.

yyyesss ,

thanks, this actually makes me feel better.

also like an old man yelling at clouds. but better, nonetheless.

Steve ,

Sadly it may be the speed of light.

All these intelligent species are simply trapped in their own solar systems for all eternity by an unbreakable natural law.

Cryophilia OP ,

That is very sad.

Aggravationstation ,

But surely generational ships would get us over that?

robolemmy ,
@robolemmy@lemmy.world avatar

AFAIK there is no known energy source that would keep a generation ship powered for the duration of an interstellar flight.

The person to whom you responded is half right. The speed of light is half of the barrier to interstellar travel. Entropy is the other half.

SkaveRat ,

just reverse entropy

Cryophilia OP ,

INSUFFICIENT DATA FOR A MEANINGFUL ANSWER

rovingnothing29 ,
@rovingnothing29@lemmy.world avatar

import fuckit && !!

groet ,

Would you need a power source? If you aim your ship correctly, then put everything alive into cryo, the ship could go completely dark, vent all heat and become a frozen rock. Then after [very long time] the ship enters the vicinity of a different star and can be reactivated and unfrozen using solar energy.
You dont need energy to maintain cryo if the whole ship is at 1° kelvin.

(Of course that relies on cryo sleep being possible)

Cocodapuf ,

Or synthetic life. (Robots)

groet ,

Only if they can be turned off (same as the cryo sleep). The whole ship either has to have enough energy to last potentially 100000 years (no theoretical power source exists like that) or enter a state of 0 energy consumption. Solar/radiation collectors dont work if you are to far from a star. Synthetic life still needs energy

Cocodapuf ,

The whole ship either has to have enough energy to last potentially 100000 years.

Well, that depends on how far you're going. If you pick a nice close target, let's say 3 light years away, you can potentially get there pretty quickly. With fusion propulsion systems you could make the trip is something like 70 years, coasting most of the way. I'd need to check the math to get exact numbers, but I recall fusion allowing for pretty reasonable trip times.

But if you can survive for hundreds or thousands of years, then solar sails become an option. Then it becomes a materials science problem of how thin can you make a sail that will still hold together. The greater the sail to payload ratio, the faster you go.

ahornsirup ,

Also, you'd need to know for certain that the planet you're sending your generation ship to is habitable for your species. While this may be technologically trivial for a society that can build a functional generation ship, the timescales for such projects (literally hundreds or even thousands of years from the launch of the probe to the yes/no signal) makes it extremely difficult to actually organise.

Cryophilia OP ,

Lol we get to the planet and find it was obliterated by a gamma ray burst 50 years ago

Hugin ,

Or just send a lot of ships and hope one or two find something good.

Cryophilia OP ,

Plus isn't the rate of expansion of the universe increasing? So at some point, even going at light speed, your destination will recede faster than you can travel.

Cocodapuf ,

Not really. Galaxies are pretty stable, stars orbit around the central black hole in the galaxy. You can absolutely travel between stars in the same galaxy, even if it takes a thousand years.

Steve ,

No. At best maybe a few reach the nearest inhabitable solar system.

amorpheus ,

Until we figure out how that is possible outside of theory, it is just that. We have no plans that address actually keeping a spaceship working on such a timescale, and keeping the crew alive on top of it.

Considering we haven't seen any generational alien ships visit, it seems like nobody else has figured it out yet, either.

Perfide , (edited )

Not really, no. Generational ships might make colonizing the nearest star systems possible, but even colonizing our own galaxy would require some kind of suspended animation. The milky way is between 100,000-200,000 light years in diameter so even at the speed of light, you're looking at a travel time that is ~33-66% of the time that humanity has even existed(homo sapiens are currently estimated to have become a distinct species 200,000-300,000 years ago)... just to go to ONE star system out of the hundreds of BILLIONS that exist in our galaxy. You're gonna need generational ships so self-sustaining and capable that the generation that actually arrives at the destination will have long forgotten the point of the trip and might not want to leave the comfort of the ship.

Still, colonizing our own galaxy is at least theoretically possible, given enough time. The real filter is just how unimaginably large the universe is. The vast, VAST majority of the observable universe is FOREVER out of our reach, as it is expanding away from us faster than the speed of light. Then there's the unobservable universe, which could literally be infinitely bigger than the observable universe for all we actually know.

Cryophilia OP ,

That's why faster than light travel is the holy grail. Without it, we're just kind of stuck.

Imagine if wormholes had zero constraints on the physical location of the other side of the wormhole though. We could open a portal to OUTSIDE the observable universe. What a mindfuck. We might even find a false vacuum decay racing towards us at the speed light, or regions of space that are contracting instead of expanding, or initiate a new big bang by opening a wormhole to an area of space where that hasn't happened...we could travel to a point where we can watch the milky way get formed, since the light of its formation is just reaching that region of space. If it turns out the heat death of the universe is just a local phenomenon, we could continue expanding forever beyond it. World without end.

AA5B ,

Generational ships wouldn’t have to reach the edge of the galaxy, just the next planetary system. There’s no reason civilization needs to remain centered on Earth, either. Think of it as a wave traveling outward, where it eventually reaches the edge, by many smaller hops. It will also eventually reach earth, where they might wonder at signs of a prehistoric civilization. Actually, think of it like the Middle East, where empires rise and fall, crusades and jihads burst through, religions rise out of nowhere, people speak many different languages. A galactic civilization could be dynamic and ever changing, distance can make us strangers to each other, the fate of any planet matter only to its inhabitants and neighbors

Perfide ,

Sure, that's an option. It doesn't really change my overall point though that anything beyond galactic colonization is unrealistic on any time scale. Our next nearest neighbor, the Andromeda Galaxy, is over 2.5 MILLION light years away, over 10 times farther than my "crossing the milky way" example, with nothing in-between to make a pit stop if needed, you have to cross the true void of space to get there.

And that's just to get the next nearest galaxy. Current estimates suggest the observable universe contains 2 TRILLION galaxies.

AA5B ,

True, you’re not getting to the next galaxy. However within the galaxy, your generation ships only need to work for a century or two per voyage. That’s at least conceivable

treefrog ,

Information can travel at light speed. So, I think there's more to it personally

Steve ,

Light speed is very slow

Perfide ,

There doesn't need to be more to it than that. The observable universe is over 93 billion light years in diameter. That means even at the speed of light, it would take over 6.5x longer than the universe has even existed for anything to cross that distance... except the universe is expanding faster than the speed of light, so actually you need to go significantly faster than light to make it across. FTL is, sadly, still firmly in the realm of science fiction, so to the best of our current knowledge most of the universe is permanently inaccessible.

Kyrgizion ,

The most boring one: most species off themselves before they fully get off their starting planet. We will go the same way. Take your pick from climate change, war, pandemic, ... or even a combination of several!

nova ,

I agree. The threshold for becoming the "dominant species" of a planet is so low that the species still has its primal wiring for tribalism, competitiveness, etc. by the time it can build rockets. We humans should've had more time in the evolutionary oven to become more empathetic and cooperative for longer-term survival. Instead we have people willing (and able) to literally burn the world down to become richer or more powerful. And we have most of society cheering them on.

We've been on the verge of destroying ourselves for decades now, and humans have just barely started doing space stuff (a blink compared to the life of the universe). How in the world can anyone expect us to get to Dyson sphere levels of progress with how fragile our existence is?

jballs ,
@jballs@sh.itjust.works avatar

Unfortunately, I think this is the most likely scenario. Going from our modern technology levels, which are more than capable of destroying the world, to Dyson spheres is a huge leap that will take who knows how long (decades? centuries? millennia?).

Before that happens, we have to live together on a planet without blowing ourselves up or making the planet uninhabitable. As technology continues to advance, walking that knife edge of survival seems more and more difficult. The pessimist inside of me says that no civilization has been able to accomplish it.

Cryophilia OP ,

I disagree with your last point. I think we'll be at Dyson sphere levels in a thousand years, easily. Maybe two thousand if we an hero ourselves.

bravesilvernest ,

Personally? Nationalism & nation states. The longer they stay around, the more likely everyone is to think they're more deserving of X, and pull the literal and metaphorical trigger that leads to hitting the filter.

I recognize that individuality is very much our thing, but that will literally only take you so far.

janNatan ,

My favorite filter is the amount of phosphorous in the universe. Earth has an unusually high amount, and it's vital for life. I like this one, because as more stars die, the amount of phosphorous goes up, implying we won't be alone forever.

Anyway, look up "Issac Arthur" on YouTube for HOURS of content about the Fermi paradox and potential great filters.

Cryophilia OP ,

Thanks, I'll check it out!

janNatan , (edited )

I'm gonna add to this by saying phosphorus may be my favorite, but I think the most likely filter is just time, twice.

Do you know how unlikely it is that earth has been habitable for so long? Do you know how long life was single-celled? One of the theories for how advanced (eukaryotic) cells formed was the combination of at least three different branches of life into the same cell! Archaea (cell wall), bacteria (mitochondria/chloroplasts), and viruses (nucleus). Do you know how unlikely that sounds? Do you know how long it would take for that to happen randomly? Most planets probably aren't even habitable for that long. Once we became eukaryotic, we started progressing much faster.

Then, keep in mind, the life has to continue to exist for billions of more years while it waits for the advanced life to happen again within the same section of the galaxy. So, time is two filters - both behind us and in front of us.

PrettyLights ,

Throwing in another similar YouTube suggestion of John Michael Godier

https://www.youtube.com/channel/UCEszlI8-W79IsU8LSAiRbDg

JayTreeman ,

Capitalism
I can imagine how capitalism could be inevitable. I can't imagine enough controls on it to make it sustainable

TheBananaKing ,

  • space

  • time

We've been producing noticeable radio waves for a matter of decades. We've been capable of detecting even super-powerful, super-deliberate, super-targeted broadcasts for even less time.

And on top of that, it doesn't look as though our civilisation is going to exist for more than a handful more decades, in any detectable-from-light-years-away form.

The chances of that onionskin-thin slice of lightcone intersecting with that of any other civilisation out there seems ludicrously remote.

bear ,

Life finds a way to end itself. There's an ongoing mass extinction event caused by humans. Completely preventable by the way. But we do not prevent it.

FaceDeer ,
@FaceDeer@fedia.io avatar

We actually spend a great deal of effort preventing it. Environmentalism is a really big thing these days.

But even if we didn't, it's not an extinction event for us. Humans are actually doing extremely well.

whotookkarl ,
@whotookkarl@lemmy.world avatar

There's been at least 5 mass extinction events we are aware of where I think over 80% of all species become extinct. I'd probably guess one or more of those could do the trick.

SeikoAlpinist ,
@SeikoAlpinist@slrpnk.net avatar

We're still new to the game, and we have no idea what we're looking for.

Cryophilia OP ,

Same thing everyone is looking for.

fart_pickle ,

I read an article about Fermi paradox (I cannot find the link) that stated the humans are one of the first intelligent beings in the universe. That's why we haven't encountered any green men so far. We just might came too soon to the party.

Cryophilia OP ,

Definitely possible. I've read that the projected end of our sun is a "black dwarf", and that our sun's generation of stars is so young that there currently aren't any known black dwarf stars anywhere in the universe.

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