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.
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.
But surely generational ships would get us over that?
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.
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.
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
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.
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
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.
No. At best maybe a few reach the nearest inhabitable solar system.
Information can travel at light speed. So, I think there’s more to it personally
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.
Light speed is very slow
That is very sad.
Boy, Lemmy sucks donkey dick. For every one legitimate answer there are two or three edgelord answers like “capitalism” and “the internet”.
Here’s an answer that hasn’t come up yet: cooperation among mono cellular organisms. I don’t mean the development of polyp analogues or colonies of single celled organisms; I mean getting down to mitochondria. Brace for wild oversimplification.
Before mitochondria, life had a hard time creating enough energy to do much more than barely stay alive. The current line of thinking is that one organism ate another and didn’t digest it. The two organisms worked symbiotically, one handled energy production and the other handled getting food and staying alive.
Just about every living thing utilizes mitochondria and if the current idea that mitochondria were actually symbiotic organisms is true, that means that what was likely a chance “sparing” of prey is the underpinning of all complex life.
The odds of that happening are ridiculously low. There could be simple life in tons of places even within our own star system, but if the mitochondria-like symbiotic capture never happens for those extraterrestrial organisms, then complex life is probably unlikely to develop.
Edgelord teenagers are a plague on lemmy
A - fucking - men
Still not as bad as reddit though
Good answer. This seemed relevant enough to share, it’s certainly interesting. https://newatlas.com/biology/life-merger-evolution-symbiosis-organelle/
your paragraphs complaining about it are a lot more annoying than the people who might not be being totally serious on the internet for a minute.
If by “paragraphs” you mean two sentences, sure.
If you’d bothered to read past those two sentences you’d see that I was making an offhand comment before answering the question.
nah if you open up just insulting all the people around you, I don’t owe you reading the rest of your post.
Case in point for Lemmy being a shit hole.
Maybe cooperation is hard wired just like competition. It might be less likely but hardly impossible.
I’d hardly describe it that way. It took untold trillions of predator/prey interactions over the hundreds of millions of years that single celled life existed for it to happen. That’s more or less brute forcing the problem and it took geologic timescales to happen.
If you ask me to point at a hurdle stopping civilizations from developing that looks awfully reasonable.
Ultimately we don’t know much about that era of time, but I suspect it was less like fumbling around for millions of years looking for a light switch, and more like the gradual warming of the planet with warmer and cooler seasons/years.
Iirc at least one of the other things related to development of eukaryotes was that atmospheric oxygen had to first be generated by early cyanobacteria.
So maybe that proverbial light switch was being flipped millions of times through random encounters but only became more viable after the voltage (atmospheric oxygen levels) became high enough. Maybe that’s the reason it took hundreds of millions of years, because transforming by bacteria just takes that long.
We just don’t know unfortunately. However, we DO know about species getting wiped out by asteroids or human cultures getting wiped out by disease or conflict with superior cultures. Any of these filters seems more of a hurdle to me than the development of eukaryotes.
I think that the great filter/fermi paradox is a combination of two facts,
- 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.
- 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.
Accidentally replied instead of editing to fix a mistake. Disregard comment.
An alternative is we are among the first. Third generation stars are the ones that have planets with enough heavy elements to allow for complex chemistry. Sol (our star) is thought to be among the first batch of third generation stars in our gallexy.
Light speed does seem to be the upper speed limit for the universe. Talking that into account we probably haven’t had a chance to see other early life as it would likely be spread pretty thin right now.
This is my favorite, mainly because it’s been well argued by some respectable scientists.
Another is that we’re in a simulation, and aliens aren’t part of it. There are also some very good statistics pointing to the simulation theory, from just sheer scale.
Yeah, I have a gut feeling that a lot of the variables in the Fermi equation are a little too generous.
I do agree that in the grand scale of things we’re actually very early. That alone would explain a lot.
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.
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.
Thanks, I’ll check it out!
Throwing in another similar YouTube suggestion of John Michael Godier
It may very well be republicans
Everyone is talking about society or physiology stuff. That is just things that might get humans.
Stars going super-nova is the real great filter. Our sun is 4.6 billion years old. Life started 4 billion years ago. In 4 billion years, the sun goes supernova. We are halfway to the end of the earth.
Smaller stars last longer, but have smaller ranges that life can exist in - and planets tend to move in or out in their orbits. Bigger stars have giant habitable zones - but some large stars born when humans took their first steps are in their last decades of life. You couldn’t get from the pyramids to NASA in that time, never mind the 4 billion years it took to get to humans.
I think it’s supposed to actually less than that, the sun’s luminescence will increase over the next 1 billion years to the point that it will boil off the earth’s oceans. No life will be able to exist past that, and earth will just be a barren rock in orbit for the next 3 billion years.
Well I’m doing my part to make sure the oceans are full of Arctic ice for the great boil off
When they do boil off they need to make sure to have a hell of a lot of cocktail sauce and melted butter on hand.
While that is true I would counter point that humans have a bit of a handicap as earth got hit by a big astroid that killed just about everything on it making terran life have to start all over again but at the other hand I saw someone else on here mentioned that oil has given us a head start at space ferrang advancement and oil is made from dead life so granted I haven’t done much reacerch on how oil forms naturally but I do wonder if we would have oil if earth never got blown up but on top of all that there are theorys that mars used to have life so if astroids haven’t interfered with our solar system intelligent life may have formed faster and maybe twice also there used to be multiple species of humans in the past so maybe 4 or five times in the same solar system
That is an interesting idea that is not typically considered in the drake equation as far as I know. That could significantly reduce the chance of finding intelligent life elsewhere.
I think it is in the drake equation effectively, it factors into the length of time that the civilization might send and receive detectable signals - It doesn’t say why the Civilisation might collapse, but the planet becoming uninhabitable is surely one reason. On wikipedia for Drake Equation the Carl Sagan specification of L is in terms of the “fraction of planetary lifetime”.
I think a missing factor might be how directional transmission and receiving is, if we can’t broadcast to and listen to the whole sky equally then we might have a 1/r-cubed type issue with the chances of both listening and transmitting with enough strength/energy at the same time.
Honesty, I don’t think that there is a Great Filter. The Fermi Paradox strikes me as not very well-reasoned. A whole hell of a lot of things would have to go exactly right for civilizations to make contact, rather than it being the default assumption. There are lots of filters, not just one Great one.
But the closest to a Great Filter is that space is really, really. stupendously big. The chances of even detecting each other across such distances is vanishingly small, much less traversing them. Add in the difficulty of jumping the metabolic energy gap to become complex life, and that could reduce the density of civilizations down to a level that they’re just not close enough to each other in spacetime to admit even the possibility of contact. And we’re hanging our hat on some highly-speculative concepts like alien mega-structures harnessing whole solar systems to allow detection.
I think a lot of persnickety, smaller filters combine to make interstellar contact between civilizations against long odds. Perhaps the best we’ll get is spectral signatures from distant planets that are almost-conclusive proof of some sort of life.
I think you’re probably closest. There aren’t “filters” so much as we live in a universe that can only support life on a highly contingent basis, entirely by accident, at random intervals. It’s filters all the way down, really. None of us are getting out alive, might as well enjoy it while it lasts.
I think at some point, almost certainly not in our lifetimes, we’ll detect the spectroscopic signatures of a planet that has an atmospheric makeup that HAS to be from life, but with no detectable signs of any civilization. Just nonsentient life. And we may never be able to get there.
seriously though, I think life on other planets probably just usually evolves underground, so even if they develop some sort of intelligence they’re not looking up at the sky so they have no motivation to explore beyond their atmosphere no matter how advanced they get.
there was a planet in The hitchhiker’s Guide to the Galaxy universe that had thick cloud cover so that people never even conceived of an existence beyond their planet. when a spaceship crashed there, it never even occurred to them that it might have come from the sky
Howabout a reasonably advanced civilization destroying itself and its homeworld after exploiting and then running out of petroleum?
Oil has a bad reputation but how lucky we are to have it. How does a civilization on a planet without hydrocarbons make the leap to a technological species?
It’s not impossible, but it’s got to be a lot harder.
Kelp farms? Domesticated bamboo? We need large areas of land to grow food anyway, we just skipped the charcoal agriculture step. Lathes and the three plate method are the real heroes of industry any way.
A slower ascension into the computing age could mean a more stable set of cultures and a more uniform global situation to avoid anthropogenic filters. Bright candles and all that.
I think it’s a fair thought that any form of life doesn’t perfectly recycle their resources and all forms of life give off waste for other life to utilize. That said, a reasonably advanced civilization might just inevitably grow to the size where the waste they put off makes their planet unlivable for them before they can take action to control it.
For us, it’s carbon dioxide.
Don’t forget plastics and pesticides! Those get everywhere, and many are bioavailable by design.
Even if you had a super intelligent species that can make Dyson spheres and travel at the speed of light the observable universe is beyond vast. I don’t know much about cosmology or our ability to detect light but given humans have only been looking into the sky for a couple centuries, not being able to see a thimble in the ocean seems like a non issue. I think if you scale the observable universe down to the size of earth the speed of light becomes 0.05 mph.
We’re currently in it. Failing to create a clean, renewable, and scalable energy source powerful enough to run a society that is ever increasing in both population and technology without destroying their only inhabited planet has got to be the most common great filter.
Asteroids strikes, super volcanoes, solar CMEs, and other planetary or cosmetic phenomena that exactly line up in both severity and timing are too rare IMO.
Every society that attempts to progress from Type 1 to Type 2 has to deal with energy production. Most will fail and they will either regress/stagnate or destroy themselves. Very few will successfully solve the energy problem before it is too late.
A filter for sure, but not a great one. Call me optimistic, but I don’t think that will set us back more than 10.000 years. If humanity can survive, society will re-emerge, and we are back here 2-3000 years into the future.
Is +5°C Earth a good place to be? No. Will the majority of humans die? Absolutely. Will the descendants get to try this society thing again? I believe so.
On a cosmic scale 10.000 years is just a setback, and cannot be considered a great filter.
Unfortunately we’ve pretty much used up all easily available resources. Anyone ‘starting over’ would have a much harder time getting the things they need to really get the ball rolling again.
When humans first discovered gold they practically only had to scoop it out of rivers. You’ll be hard pressed to find any streams with such appreciable production anywhere in the world today.
I think that is thinking a bit too narrow. A lot of the stuff we use today might just be our bronze to our successors iron - you can build an unstable society on either. And what we do use up today could still work if used more efficiently - we might not have enough rare metals to give everyone a smartphone in the post-post-apocalypse, but I could see us still launching satellites if only big governments had computers - because they did.
We’ve already discovered fission and photocells. We’re past the point of needing fossil fuels for a new civilization (or existing civilization). Fossil fuels are only hanging around for economic reasons.
Assuming that knowledge and resource locations are retained. Roman’s had great concrete. Took a long time to reestablish what Humans already had and mixing raw materials is not complicated.
After the Roman Empire, the use of burned lime and pozzolana was greatly reduced. Low kiln temperatures in the burning of lime, lack of pozzolana, and poor mixing all contributed to a decline in the quality of concrete and mortar
We need a Foundation project to restart society If we want to avoid this. Worst case solar cells becomes myth like Greek fire.
evidence of human existence has only gotten what, 150 lightyears out into space?
Eh. The amount of oxygen in out atmosphere is pretty much impossible by non-living processes alone iirc. Anyone who can do astro-spectroscopy can probably tell there’s life here, from thousands of light years away.
and if life is as abundant as we think, how are they going to tell the difference between intelligent and non-intelligent life
Life is so rare, finding ANY life is worth investigation
that has nothing to do with why I asked that question lol. if you have to investigate every single one that shows signs of life, that would mean investigating a lot of worlds before you find any with intelligence.
By the color of their hats /jk
My thought is the evolution of intelligent life itself. If you think about it, intelligence is contrary to most of the principles of evolution. You spend a shit ton of energy to think, and you don’t really get much back for that investment until you start building a civilization.
As far as we can tell, sufficient intelligence to build technological civilizations has only evolved once in the entire history of the Earth, and even then humans almost went extinct
I would say it’s the size of the universe and the fact that it is still expanding at an accelerated rate.
If the speed of light is really the “top speed” of the universe, it is inadequate for interstellar travel. It is barely good enough for timely communication, and not really even that.
Life can be as likely as it wants to be, but it seems to me that we’re all quite divided, to the point of not being able to communicate at all with other potential intelligent species.
Isn’t the fermi paradox specifically dealing with detection tho? Not just travel or communication.
I suppose I was focusing on detecting some sort of communications. It still matters that when we see objects at great distance in space, it’s the objects in the distant past
This universe being unfriendly to interstellar and especially intergalactic travel would seriously hamper a galactic civilization, and thus be less likely for us to notice them.
There might be hundreds of civilizations out there, each having only expanded to a few dozen stars, not caring to go further. Even the makeup of the interstellar medium might be incredibly dangerous, basically necessitating generation ships to cross. Large scale expansion might simply be too hard.
That expansion at an accelerated rate - that’s just so eerie when you think about it. The furthest objects we can see right now will slip away out of reach forever for the next generation, and so on. It’s crazy to think that as time goes on, there will be less and less universe to observe.
That’s something really interesting, though. When we look at distant objects, we aren’t limited by the distance they’re at right now. We’re limited by the distance they were at when they emitted the light.
So the observable universe is still growing because the edge of that bubble is such a long time ago that everything was still much closer together.
But the light that reaches us is constantly getting stretched (red-shifted), so I’m not sure that our bubble is growing. Instead when they’re stretched too thin, we won’t be able to see it. I’m not 100% sure on the expansion rate of the universe and the pace of red shifting. Also, eventually all the galaxies are expected to be pushed so far away from each other due to the pressures exerted by Dark Energy, that soon we’ll only be able to see just the stars of our Milky Way.
One of the weirdest facts. One that really makes you feel so small.
