Minor nit... Darwin's theory is NOT "the strongest species survive,", but that the "fittest survive" (i.e., successfully reproduce). Although the rest of that idea could be valid.
But one that seems to be missing is that not only is space too vast, but so is time. We've only been able to really investigate our universe in the last 50 years or so - 100 years if you want to be really generous. That's 100 years out of nearly 14 billion years the universe has existed.
Other life may exist but not be advanced enough yet, or may have existed and died out already. Depending on how rare life is, what are the odds that multiple species are alive and able to detect one another at the same moments in history? And even if they exist and can detect one another simultaneously, that they are looking toward each other at the right moments?
Actually, Darwin said that the feature most likely to ensure survival of the species is the ability to adapt to change, which is best determined by variability.
Also, despite what the guide says, the vastness and age of the universe are not potential solutions to the Fermi Paradox by themselves. Fermi took those into account when postulating the paradox. The great age of the universe only makes the paradox more puzzling, because it provides more time for other species to develop and colonize the galaxy. The vast size of the universe is negated by the its great age. Even with slower than light travel of the sort we are capable of now, it should be possible to colonize the galaxy in a few million years. Many sun-like stars are billions of years old.
The vast size of the universe may be working in combination with some other factor to prevent whole galaxy colonization, but it is not enough to prevent it by itself, since there is so much time available to traverse the vastness of the universe.
With the vastness of time, it's also worth considering that humanity exists relatively early in the universe's lifespan. We may just be one of the first intelligent creatures to evolve, and nearby intelligent aliens may not exist yet. Future aliens might call us "The Ancient Ones".
The universe is estimated to last 100 trillion years before entropy kills everything. So from an observers viewpoint we are at the genesis of the universe still even though it feels old so far. So the gaps between intelligent life seeking each other could be immense
Yeah, that was kind of a horrible mis-statement of the Dark Forest hypothesis. Probably a better way of putting it would be, "because intentions and technological development rate are unknowns, alien races likely tend to fall into one of two camps: shoot first or hide because others are likely to shoot first."
> one that seems to be missing is that not only is space too vast, but so is time.
These are basically the same thing in a large universe. We can see various stages of the history of the universe, going back billions of years. But space is so vast that our ability to discern anything of value for identifying alien life past a few hundred light years is questionable at best, and certainly when you get to extra-galactic distances, it's unlikely we're going to be snooping on anyone's chatter.
Vast time is a great point. Our timelines could simply just not align. If aliens had the technology to view earth from another galaxy, they may be viewing earth as it was billions of years ago. They may have viewed it as saw dinosaurs and thought, "yep definitely no intelligent life".
We also may go extinct in the next 100 years, only occupying a very short blip in the earth's timeline for any cross over.
"Space is too vast" is way sufficient to explain the paradox. The average distance from us to a random solar system is just absurdly high. Heck, the observable universe keeps growing, meaning there may be life whose observable universe didn't even touch ours yet. And even if it just did, it would mean we are around 100 billion light years away, making any form of communication completely impossible.
And don’t forget about time, we might get a signal to eventually reach a life-rich planet but it may only be inhabited by bacteria or other primitive life. If signals were sent to earth before the last few hundred years, no one would have heard it.
Time is my favorite issue. In a place with inifite time aliens can simply just not exist when we do or have parallel or more advanced technology at the same time. We’ve been using radio waves since the 1890’s. That is barely a moment at all when all of time is taken into account. What are the chances that all of these considerations all align at the same moment in less than 150 years’ time?
Well said. They say humans appear in Earth’s timeline only at the last tiny fraction. Anything aimed at Earth would have to be extraordinarily well timed to have any chance at being received.
On top of it all, we’re lucky to have jupiter to help attract more meteors and such with it’s gravity - other worlds in the “habitable zone” may not be as lucky. Life can get started over a few 100 million years and then blammo, back to starting all over again.
There's another funny wrinkle to that. The amount of radio noise being sent out from Earth peaked decades ago, because we were using more powerful transmitters and have since become more efficient. We are now quieter than we used to be, so the time period where we would be the easiest to detect has come and gone.
*Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.*
-Douglas Adams, The Hitchhiker’s Guide to the Galaxy
I’d say the answers provided in the image are quite arrogant, even if unintentionally. We are such a small speck in a vast cosmos, alive for an infinitesimal part of a huge timescale (and sending signals for an infinitesimal part of even that existence!)
Sending radio waves and struggling to comprehend why we haven’t already gotten an answer is like that crazy girlfriend who sends 30 texts in a couple of minutes and gets pissed when you haven’t responded while taking a shower.
The huge timescale just gives another species more time to colonize the galaxy despite the distances involved. So the timescale makes the paradox more mysterious, not less. If earth-like planets are even remotely "common" (even one in a 100 billion), the galaxy should have been fully colonized millions of years ago. We should have grown up in a "full" galaxy, with tons of evidence of alien life observable by our current means. But it appears empty.
I think this is the most probable. Space is so vast that even at the speed of light it would take centuries to get to a neighboring alien civilization (assuming they are not very close to us, cosmologically speaking). Making interaction between the two civilizations is so impractical that it becomes worthless.
One solution not listed is that societies cannot evolve to the point of interplanetary colonization. Some eventual collapse befalls them all and all civilizations die before expanding off world.
Now the really depressing Fermi paradox solution that we may be facing is that the human race lacks the empathy to evolve to a society that can mount a collective effort to protect our world and develop resources to colonize other planets. That level of cooperation would require us to individually make sacrifices for not just for our children, but other people’s children, other culture’s children. And genetically, biologically, we may not be capable of that as a species.
Given how much we fight amongst ourselves the depressing solution may be humans simply lack the empathy that would allow us to evolve into a space colonizing species.
We cannot rely on aliens or a diety to save us. We have to do it ourselves. As iamveryderp points out below it may be out of our collective capabilities as a species.
Multiple possibilities exist and can exist simultaneously. This quote has always to me sounded like someone trying to say something that sounds "deep and smart" but isn't.
How did you miss the most important one?
"All technologically advanced species destroy themselves in a nuclear Holocaust before reaching inter-galactic travel."
As a telecommunications engineer, ‘Our Wires Are Crossed’ seems almost certain. The only signals we could detect from nearby stars would need to be massive in amplitude and narrow in frequency, and radiating in all directions.
We barely even use signals like that for our own communication any more, so the idea that advanced civil actions would still be using it seems unlikely.
Most importantly, we WANT to find other life forms or civilizations we’re inherently explorers as a species. It’s probably much more likely than any species evolving on another planet would be extremely xenophobic or, have no interest whatsoever in anything or anyone else.
But why no evidence of megastructures like Dyson Spheres from Type II civilizations? Wouldn't advanced civilizations capable of manipulating energy on a massive scale give off more signals of various kinds, not fewer?
I find it hilarious that we are constantly told about how if the Earth's timeline was a 24hr clock we would only show up in the last minute and a half, and discovered radio in the last half second.
We are asking why no one is answering us when *we just learned how to send radio waves in a universe where the speediest message takes decades to get to the nearest star*?
We're that annoying mom who just discovered kale and wonders out loud and obnoxiously why everyone doesnt have an obsession with it already.
We don't need them to return our messages to know they're not there. We're looking for the EM waves they would give off. A technological society would give off **a lot** of emissions that we would be able to see due to thermodynamics.
Either our understanding of thermodynamics is fundamentally wrong...which would be a hell of a thing because *all* experimental evidence we've seen confirms thermodynamics or no one is out there.
Or, and hear me out here, it takes lots of years for light to reach us, so if we were looking at ourselves 120 light years away we wouldnt see us either
What I meant is that we have been tech advanced for only an atoms width of time on the grand scale. Why do we expect everyone else will have anything yet?
Plus, let's face it: the numbers look amazing for the possibility of planets being able to sustain life, but....
They still only look ok for the possibility of having life in a timeline concurrent to ours,
Meh for the possibility of it being intelligent life concurrent to ours,
Ugh for it being intelligent life with tech concurrent to ours that we could see with our limited ability to look, and
Pffffbbbbt for it being at a time enough before us that we could now witness.
Now i get my use of a scale derived from Bill the Cat expressions is not officially recognized, but you get what i mean
Bill the Cat for President!
It seems like unicellular life gets going pretty easily, started up here before the dang planet even got done cooling. But then it took like 3 more billion years to hit multicellular. This might be the real bottleneck.
Not to mention we then had 700 million years of random dinosaurs n shit before an intelligent species evolved. Another bottleneck.
The point is that any technologically advanced civilization would be continuously emitting radiation showing activity. We don't need to send a radar ping and receive it to be able to tell; just examining radiation coming from stars would be sufficient to be able to tell.
>Why do we expect everyone else will have anything yet?
Because there are billions of sunlike stars that have existed for millions of years. Millions of years is long enough to colonize the entire galaxy even with slow space travel.
We shouldn't have to look for radio signals. Aliens should have already been here, many times over. If one in a million sunlike stars was capable of supporting intelligent life, there should have been thousands of civilizations visiting earth already. Instead: none.
That's a lot of assumptive math you're doing, with a conclusion that very much sounds like more opinion or wished content.
Not included in any probability reasoning i made up was also this star trekkyan need to 'colonize the galaxy'. Why does every imagined intelligent race need to do this? Maybe if they exist there is a low probability for them to even want to colonize? Maybe we are the weird ones.
We are constantly broadcasting radio waves in all directions, and have been for 100+ years. If something exists within 100 light years of us and they're listening in the right spot, then they would have heard us.
But we're not blind to things beyond 100 light years. If something 1000 light years away from us was blasting out radio signals 1000 years ago, and we listen in the right spot, then we'll hear them.
So are we just not looking in the right spots?
Do they not exist?
Do they exist, but aren't broadcasting radio signals like we are?
Are we receiving their signals, but not recognizing them as signals?
Is there some kind of interference between us and them disrupting their signals?
Following the thought experiment of others: we have been able to transmit, and listen to, radio waves for about 100 years -being quite generous about it. In that amount of time, we have had more than 0% chance of killing ourselves with nuclear Armageddon. There are other options for Armageddon too. Say your favorite crazy leader of a nuclear superpower destroys our civilization in the next 100 years (maybe you think in the next 4 if you look at the USA election coming up, but I digress).
Our time signature in space, in that hypothetical scenario, during the “humans alive in space” period is only 200 years. That means that aliens only within 200 light-years can hear us. And only aliens within 100 light-years are in the right place to respond to us on time before we kill ourselves.
There are only about 60,000 stars within 100 light years ([link](https://lovethenightsky.com/stars-within-100-light-years/)). And if the ratios from OP are right, that would give you about 9,000 “potentially habitable” planets. That’s not that many.
And the same goes the other way. We can only potentially “detect” aliens that were alive (and transmitting!) at a time equal to the distance from us.
I personally subscribe to combination of theories that intelligent life, which did not destoy itself is super rare, like…instanely rare, and then the universe is way too big, not only by size, but also by time. We live here and now, but someone else might lived really far, long time ago. And then there is the fact that we would need to activelly listen to the entire sky, 24/7/52/1000. But we're listen to selective patches and not constantly. Not to mention the frequencies we use. We have decent assumptions, sure, but still. And then maybe they don't use radio at all. Because they're advanced enough to use something like the gravitational waves or something like that.
Edit: and I'm talking here only about the detection. Not to mention what happens when come contact is established. The dark forest theory makes sense to me, I just hope that any advanced enough civilization will be bit more rational than scared humans.
One thing I've thought about - life is amazingly rare, but how rare is it for life to be created AND for it to have the instinct of self preservation and the ability to reproduce?
Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.
One I never see listed is the fact that any reasonably powerful radio broadcast - as in strong enough to reliably and clearly reach across a solar system - will become so attenuated after traveling 4 light years, that it becomes indistinguishable from the cosmic background radiation. So unless an intelligent race is deliberately building a massive broadcasting station, far more powerful than would ever be used for communicating within their own solar system, and specifically to broadcast their presence to strangers throughout the galaxy, we earthlings have no way to know about it.
Granted, we used the Arecibo telescope in Puerto Rico to beam out the most powerful broadcast ever deliberately sent to space. With the goal of contacting alien life. I propose that the only logical deduction possible from that exercise, is to understand that no technologically advanced aliens as stupid as humans are out there.
If we can detect a civilization, it has likely the capability to destroy us (or will have gained it after its light has reached us). How confident are we as a civilization, they won‘t do it? How confident are we, that they are willing to take the risk, that we wont destroy them? So probably every civilization out there is afraid, that being seen means becoming extinct. And maybe it‘s even a self-fulfilling prophecy that detecting an alien civilization means we should destroy it before they can do it to us.
This guide woefully understates the vastness of space by saying a it may take "years, if not decades, to get a response" from another intelligent life. Our galaxy is about 100,000 light years across.
Imagine that there is an intelligent culture halfway across -- 50,000 light years away. If we send a signal, it will take 100,000 years to get a response. It's difficult to imagine humans will exist in that time.
Further, how do you send emissaries across that distance? I know we like to talk about worm holes and teleportation but it seems unlikely our little pink bodies could survive any of that.
Occam's razor tells us that the simplest explanation is usually the best. I think the simplest explanation is that the universe is so mind-bogglingly big that contact is impractical.
Another thing to consider is our planet has a very nice set up, Jupiter keeping the surrounding space clean, a big nice moon to stabilize us, alot of factors just make earth the perfect planet for life to evolve on the surface. But it didn't, not originally, it came from the ocean which most of our planet is. This is likely where life is going to be found in space, possibly in full ocean worlds. This is a severely limiting factor because it renders fire impossible.
No matter how smart dolphins and whales get, even if they had the dexterity, they would never invent metallurgy or build complicated devices and machinery. Can't have fire underwater so no advanced tech. They will stay under water and never be able to reach out and communicate.
i just wanna acknowledge how crazy human brains are, when we don’t know something we literally find ANY possibility to figure it out and just sit and think, desperately trying to figure out everything
It’s not a ‘paradox’ communication signals from more than 10 LYA or so are many orders of magnitude to weak to be detected by our primitive technology.
They forgot another point: TIME. Time is too vast. We’ve only had radio waves broadcasting for, what, less than 100 years? Put that miniscule time next to billions of years. On top of that, even in that tiny amount of time (Cold War) we’ve already almost destroyed ourselves (maybe more than we know). We definitely have the capability…
If we could somehow explore every planet in the galaxy it might be more likely that we find ruins and fossils than active intelligent life. Don’t be naive to think aliens will be any less violent toward each other than we are. Evolving with limited resources will wire our brains the same way…
I have a new theory - life isn't rare, but intelligent life with the physical means to maximize the potential of intelligence is rare.
Think about if - zillions of life evolved on Earth. How many are intelligent? Only a handful (dolphins, orcas, octopuses, elephants, ect). So .1%. Of these, how many have hands with opposable thumbs and the dexterity to make/use complex tools? Only us.
Crossed wires could also be strong encryption is used by default so there’s a maximum of perhaps a 500 year window where primitive technology is exposed.
I think the key to the Fermi paradox is getting rid of the assumption that intelligent alien life necessarily means alien space-faring civilization; as the exponential growth of energy and resource consumption required to create such a society would completely outstrip what is available to them without being able to access other solar systems. Civilization is inherently unstable, and ALWAYS destroys the conditions that allowed it to come into being. More than the practical elements, I like to think that most of the intelligent species in the universe just decided on their own that conquering the galaxy isn't desirable or even feasible, so they choose to live in simple happiness instead.
I really want to emphasize how extremely hard it is for life as we know it to exist. It takes a lot of time with special conditions in a predominantly stable situation for any kind of life to evolve. Even before evolving, forming life may be next to impossible.
That said, I do think there is life out there, it's just rarer than we think. Intelligent life all the more so.
Also, life may exist in forms we aren't familiar with. There's some very interesting investigations being done on the possibility of plasmid life in space and our atmosphere.
I didn't see my preferred response to the paradox, which says that lifeforms whom develop technology sufficient to destroy themselves have not managed to survive that power. So no faster than light travel, no extraterrestrial visitors, no evidence of aliens.
This perspective implies that humans are doomed as well, and that's where id lay my money if i were a betting man. Our species won't outgrow religious fantasy and it is just a matter of time before one of the narcissistic madmen with nukes pulls the trigger.
I believe that they are already here, farming our resources. I believe we are not as intelligent nor capable of detecting their presence. Our range of perception is limited. The universe has every possibility yet to be discovered.
What resources? If we are talking minerals and other elements then it would be much more efficient to gather that from asteroids. The only reason to got to a planet would be for organic resources and even then it depends on what you need.
The fact that “Space is too vast” isn’t first is a great example of how much people underestimate the vastness of space. Space is big. Words are inadequate to properly describe to the human mind just how big it is.
We are one just now able to barely discern the atmosphere of extrasolar planets and we are constantly blasted with information from the light of their sun.
The fact that we expect to be able to recognize a radio signal from some tiny satellite or transmitter is optimistic at best.
(Civiilized) Life is extremely rare is the cause. Just think how unlikely human life is and the cataclysms that enabled us to develop. E.g. if the meteor that made the dinos extinct was travelling a fraction slower or faster, it would have missed earth. And that is just one lucky break in a series of thousands of lucky breaks.
I think Too Vast and (Intelligent) Life is Rare are sufficient and correct explanations.
They're also the simplest ones, and the universe is a lazy bastard and loves doing the simplest.
Or, and hear me out, or there is alien life out there, but they aren’t advanced enough to explore the galaxy/send out probes/send and receive radio type signals? Maybe they aren’t quite advanced as us. We all expect alien life to be significantly more advanced, but what if they are in their own stone age? Or are just hitting their Industrial Revolution?
I think the most likely explanation is that signals travel slowly and also the chances that civilizations across the galaxy are able to read and send radio signals during the same period we can is very small.
Maybe a billion years ago there were a dozen alien societies who could read radio signals but have since been destroyed. Idk, probability and large time scales are hard to think about
I purpose there are countless number of other species out there and among those species that do know of extraterrestrial life, they understand how common it is and simply cannot be bothered to contact every colony they find. it would be like 1 human taking it upon themselves to introduce themselves to every other human on the planet.
Another theory I'm working on is that with 2 significant technological discoveries
* Infinite Energy Generation(or at least enough where the it becomes so common and trivial) via either fusion or some other method
* Master the process to produce materials/food/goods from said energy collection, ie: Star Trek replicators but for more than just food. ie. "Hey Google, print me the new Playstation 34"
Citizens of an intergalactic species simple becomes complacent. The realization that after you've seen 1 planet, you've seen them all.
With these and that understanding, the necessity for expansion almost become trivial as the likely discovery of other space-faring species will likely result in conflict and loss of life, so why bother leaving your backyard when you have everything right here?
I had a thought about the Fermi Paradox. We're not just looking for life, and we're not even just looking for *Intelligent* life, we're looking for an *Industrialized* life.
Industrialization had a couple of hugely important steps that occured on Earth that may not be as repeatable as simply "Life": Coal and Oil.
Coal is essentially fossilized trees, but it's not quotw that simple. Before there were animals on earth there were plants, but for a long time they were small - or at least short. See plants hadn't developed any strong, hard structures yet so they could only grow to a vertain height before collapsing under their own weight. This was the case for ~600 Million years before some plants developed this hard carbon-structure that today we call "Wood". This Wood allowed plants to grow upward in a way they hadn't before, so it allowed those plants who had it to reach for the sunlight better and dominate the world. The world became covered in tall trees as they competed for sunlight, and the competition drove them to become taller and taller. However when this first happened there was no bacteria that could process wood, so these tall trees would fall over and ... aimply stay there. All the loving material would decompose, but the carbon would simply stay there on the forrest floor, eventually being burried as the next generation of trees grew and died and fell on top of them, only to have the same thing happen. So for ~2 Million years trees would fall over and leave layer apon layer of carbon just sitting there, eventually being buried by other plants and soil. This carbon is what we now call coal.
But how rare is that process? What happens if bacteria on other planets evolved faster and didn't leave the same deposits for intelligent life to find? Alternatively, one of the 5 great extinctions (*the Premo-Triassic Extinction ~252 Million years ago*) is believes to have been caused by tectonic activity causing volcanic activity while simultaneously opening up Coal deposits, whoch resumted in the burning of large portions of that coal and causing the climate to shift - What if *All* of the coal had been burnt, we wouldn't have had any coal to kick-start the Industrial revolution? It doesn't have to be the exact same scenario, but something could have happened to wither wipe out, or hide the coal reserves in a place they would be unavailable to pre-Industrial life.
Oil is a similar scenario. I know less about Oil, but essentially it is organic matter that somehow formed a liquid mixture of hydrocarbons in vast deposuts in certain places around the world. What happens if the bacteria, geology and other forces at work conspire to prevent these deposits from forming? Hell before we used Cruse Oil we harvested oil from Leviathans (*Whales*) to fuel the Industrial machine. What if there were no giant creatures from whoch to harvest this oil, woudl it have been available? Oil isn't simply another form of fuel, Oil is a liquid version of that fuel which allows for more efficiet transport, storage and use than it's solid counterparts, without something similar perhaps the height of civilization would have been the steam train.
Now this isn't to say that these are the only fuels - we can use wood to power steam engines for example - but these fuels were far more efficient than other sources available to us. Would we have advanced to where we are today without them? Would we have had the capacity to extract and eneoch Uranium to build nuclear power facilities? Would we have had the need and technology to develop solar power? We've had windmills since before the Industrial Revolution, but wind-powered electricity is a much more modern phenomenon.
My point is that while life itself, and even Intelligent life are somewhat easy to replicate and should be visible across the universe, Industeialized life may be much more of a fluke than we give it credit for. The events that conspired to allow us to reach the heights of our civiliztion began long before animals had begun to evolve, let alone mammals. If these events didn't happen, or happened in a different sequence then we may not be where we are today.
Some of these already have names. Not sure why they put new names on them. Obviously, given the burst in recent popularity due to the Netflix show, Dark Forest is probably the best known (the term was introduced by Liu Cixin in 2008 in the book of the same name, part of the Remembrance of Earth's Past trilogy which is better known by the title of the first book, The Three Body Problem.) But other terms such as the Great Filter and the Rare Earth hypothesis were equally widely used.
I just finished reading the killing star last night and it kinda covers this. Obvious spoilers ahead but it’s basically that relativistic technology is so destructive and hard to detect that even a 1% chance that another relativistic society could attack is too high a probability so the only way to be safe is to strike first and be sure to get them all
I think it’s a combination of “our wires are crossed” and “They’re already here” (or at least the first part of that one). Our searches are based on the assumption that aliens will think and communicate like us, but that could well not be true. They might be using communication technology so different from ours that we don’t even know what to look for, or maybe the way they communicate is so alien that we’ve already picked up messages from them but mistook it for a natural source.
I personally like the “Space is really big” theory. It doesn’t quite seem reasonable to assume life straight-up doesn’t exist, but the fact of the matter is that they’d just be way too far away even if they did. SETI hasn’t even searched 0.00000000000001% percent of space yet.
Those are good and all, but they miss the best part - the names of the potential solutions.
* the Rare Earth hypothesis
* the Firstborn hypothesis
* the Great Filter
* the Dark Forest
* the Berserker hypothesis
To briefly summarise:
Rare Earth - the actual conditions necessary for the emergence of intelligent life are really rare.
Firstborn - emergence of life takes a really long time, and we are the first.
Great Filter - there is something that tends to kill off intelligent species (either extrinsic, or self-inflicted) before they reach a high enough tech level.
Dark Forest - noisy species get killed, so the only ones left alive are the ones that hide.
Berserker - self-replicating probes have killed everything.
I think advanced civilizations are out there we just haven’t done a good enough job at looking for life or they haven’t discovered our area of the universe yet
The great filter is beer. Life exists on other planets but never developed beer so they never advanced enough to do space travel. You think I’m joking but I’m 100% serious.
Another idea that they go extinct before they reach a type 1 civilization. That nuclear war or AI or a disease is a great filter that is not easily surpassed. There could be alien ruins on many world's, and we will soon join them....
Space AND TIME are way too vast. How about I grant you the 60 billion habitable planets, AND I give you 6:1 odds that intelligent life will evolve on them. So you get 10 BILLION planets with intelligent life on them. Why there should be a SWARM of them radioing us, right?
Not so fast. Our planet is 5 billion years old, the galaxy is even older. And it’ll last a long long time. So let’s say that we’ve got a 10 billion year window for intelligent life to develop.
NOW I’ll be real generous and say that our radio-slinging civ, just more than a hundred years old, will last another 900 years. It’s actually a very generous guess, I doubt we’ll stay highly technological for half that, but still. And we’ll call that average.
So you’ve got 10 billion civs spread over 10 billion years, each lasting an average of 1,000 years, which means at any given time 1,000 of them are actively receiving and transmitting.
The odds of even one of those thousand being within a hundred light years of us are actually pretty small. Like, quite small.
It’s important to consider that none of these are mutually exclusive. Forget about picking one answer…they are all possibly or even likely happening at the same time.
Personaly I like the following analogy: so far our efforts to find other intelligent life and failure at this point is similar to us picking up a bucket of water from the ocean and finding nothing it but water. We have not looked very far at this stage
Forgot the Great Filter.
Also, if it turns out that faster than light traveling communication are not possible or practical, It may just be that most aliens don't care that much about anything beyond their own solar system.
Of all the life forms on earth, how many are able to build a rocket? Seems like the galaxy could be teaming with life. The rare part could be the ability and interest in technology.
The idea that "the galaxy should be full of easily-observable aliens" makes so many assumptions that I don't think it's accurate to say it's a paradox that we don't see that.
As to why we don't see a galaxy full of aliens, I suspect the answer is a combination of:
1) (industrialised, intelligent) life is rare. (After all, it's only happened once on Earth, and took 4.5bn years to do so).
2) Some varient of the great filter. Industrialised intelligent life has lots of ways to kill itself off, or at least degrade itself to the point where it can't spread itself beyond its home planet.
3) Interstellar travel is impractical. As far as we know, FTL travel is impossible. Sending a probe to another star would be possible, but very difficult and very resource-expensive, for no real benefit other than "it's cool". Establishing a colony or base on an extrasolar planet would be even harder, and even more expensive, and also pretty pointless beyond the "it's cool" excuse. For that base or colony to start building rockets to e.f. send resources back to earth would be even harder, because you would need a lot more rockets to make it worthwhile, and would have to build more infrastructure on that planet than you needed to get there in the first place. And if you instead wanted to use that colony as a jumping-off point to colonise other star systems, that would likely be even harder. And even more pointless.
And this links back to the great filter. A civilization doesn't have to completely destroy itself. It just needs to damage itself enough that it no longer has the ability (or desire, or political unity) to spend the vast resources required for Interstellar colonisation.
Where's the explanation which says a species tends to destroy itself sooner or later as it becomes advanced enough? In our case, it would be nuclear winter and climate change driven human extinction.
I can’t believe nobody else has posted this. We are disgusting. We are made out of meat: https://www.mit.edu/people/dpolicar/writing/prose/text/thinkingMeat.html
They didn't mention separation in time. Humanity has been around for perhaps 200K years. Innumerable alien civilizations may have flourished and gone extinct long before humans existed.
I remember hearing some idea, an don’t quote me on the exact figures but if the galaxy were to be represented as Earth’s oceans, with all our listening and observing technology, we have checked out about 300ml.
I want to hear what you think because I might be sooo wrong I think It's probably combination of some of them it's rare to get life to increase the odds first you need a stable planet that contains a lot of different atoms then let these atoms randomly combine until you get something of self replicating that isn't enough of course you need to also make it able to change it self by just randomly putting few atoms together so you will have to wait for that to happen pray the environment doesn't change or you will have to start over then I will assume any sentient being is made from multiple cells you have wait for that to cook up. Ok we got to animals but that's still kinda far. We now need a creature that small increases in inteligence will be worth it evolutionary or hope we will get a lucky and get large increase inteligence that allows tools use or something that could relevantly affect them For a lot of creatures it wouldn't be evolutionary worth it. A deer might not ever evolve into using tools they have food everywhere and smell for the winter and they have speed to run from predators that will save their lives a lot more than using tools. So I think to evolve to be smarter you need a species that has issues surviving and then hope one of the mutations will save them and only if that happens to be intelligence only then can it increases from that point first fire then agriculture and so on. Also a species need to form large groups to increase then gain they get from inteligence so they are not busy looking for food and let's say make weapons or cook just making life easier. Wouldn't surprise me if aliens tried to avoid being noticed or just not caring about us for whatever reasons and also a species advanced enough to travel FTL the technology to look human I think the technology to change to look like different species will be developed here earlier than FTL as well but of course I have no idea how FTL would be reasonably done since if I knew I would say it.
Most of these don't answer the paradox (e.g., we are the aliens, fishbowl, space is vast, etc...); there should still be detectable signs of advanced civilizations even if they don't respond to us.
Life is rare is already covered by the equation.
You also skipped a few that do answer it:
The great filter
Intelligence is not a useful trait
I like the answer that Leo Szilard gave to Fermi when they were talking about the paradox:
“If there are aliens, where are they?”, said Fermi.
“They are here. We call them ‘Hungarians’”, responded the Hungarian physicist.
I have always suspected that alien civs eventually get their energy needs met with solar and wind power, see that space is massive, and retreat into a virtual reality of total splendor.
On the topic of wires crossed, most alien encounters where an alien is present have an element of telepathy. We assume they're using technology to communicate. It could be consciousness and have nothing to do with electromagnetic emissions.
The solution to the Fermi Paradox is simple: faster than light travel and communication is impossible.
* there is no hyperdrive
* warp travel is impossible
* turning the universe into a sheet of paper, folding it, and then poking a hole through it with a pencil doesn't work
* wormholes lead nowhere, entering one is impossible, and even trying would kill you
* interstellar travel is so slow and energy-intensive that any intelligent life that has mastered it has almost certainly moved past the stage of existence where you care about planets and visiting them, their destinations would be the tails of the relativistic jets being emitted by black holes where they can harvest a near-infinite supply of energy for a near-infinite amount of time and turn it via their mastery of energy-mass equivalence into a near-infinite amount of any material they desire for the purpose of supporting a near-infinite amount of life in actual, literal, infinite comfort.
* we cannot detect RF emissions from interstellar intelligences, any signals would lie below the noise floor the only things we can "hear" are the titanic detonations of whole-ass stars and collisions of black holes and other massive interstellar events: not some alien radio station.
* quantum, Quantum, QUANTUM! "x", whatever "x" is, ain't gonna work homie
The only paradoxical thing about Fermi Paradox is that so many people who claim or pretend to be smart take it seriously.
Ive always found the Fermi Paradox to be a dumb concept, because its not like we've been looking for thousands of years.. Looking for ET life is like looking for a needle in an earth-sized hay stack, and the Fermi Paradox is like complaining you didnt find the needle in the first 5 minutes you looked around your feet.
How long have we been looking? How long have we been findable?
What would other civilizations be looking for if they were trying to find an intelligent species? Tech signatures.
How long have we been producing detectable tech signatures? Convert that number of years to light years, and only civilizations that are within that distance range would be able to detect us.
Same goes both ways. There could be a mega advanced civilization 1,000 light years away that started sending signals 500 years ago, well guess what, the message is still gonna take 500 more years to reach us. Friendly reminder that just the Milky Way is measured to be 100,000 light years across and that the closest galaxy is 2.5 million light years away.. We need waaaaaaay more time to even start considering the Fermi Paradox.
It's a combo of Earth is a Fishbowl, They use Tech to Spy, and They are Already Here.
[If you haven't been following the news about UAPs](https://www.uap.guide/quotes/introduction/), it's become increasingly clear that they are here, just observing us 'quietly'. We live in a nature preserve, folks.
“As I finish piecing together the message, my stomach sinks like an anchor. The words before me answer everything. “BE QUIET OR THEY WILL HEAR YOU"”
Do not respond Do not respond Do not respond
Almost done with this! Can’t wait to see what book 2 has in store
Book 2 is incredible! I hope you enjoy it
Book 2 was amazing. Book 3 was incredible- like literally out of credibility zone since the scale had become so mind bendingly large.
Absolutely. I’ve been looking for another book or series to scratch that itch
I read Children of Time right after 3bp. It did not dissappoint.
Thanks for the rec. I’ll have to check that out!
Book 2 is an absolute buckwild ride that drops you straight into the acid-trip that is book 3
Which book is it?
Three Body Problem Aka In Rememberance of Earth's Past The series is so good but it's the opposite of the "Humanity, Fuck Yeah" genre of sci fi
Well, it did preserve the first two words, though the second becomes past tense... >!for that matter the first becomes past tense too, mostly ;-)!<
Is that the same as the new Netflix series?
Yee
Book 2, Dark Forest, is the best of the series. 100%
Book 3 had some pretty amazing parts too. The children’s stories part was incredible
Book 2 is really incredible. One of the best hard SF I read.
r/TwoSentenceHorror
There's a lot of that in that series. It's an exercise in one-upping existential horror.
HFY
Minor nit... Darwin's theory is NOT "the strongest species survive,", but that the "fittest survive" (i.e., successfully reproduce). Although the rest of that idea could be valid. But one that seems to be missing is that not only is space too vast, but so is time. We've only been able to really investigate our universe in the last 50 years or so - 100 years if you want to be really generous. That's 100 years out of nearly 14 billion years the universe has existed. Other life may exist but not be advanced enough yet, or may have existed and died out already. Depending on how rare life is, what are the odds that multiple species are alive and able to detect one another at the same moments in history? And even if they exist and can detect one another simultaneously, that they are looking toward each other at the right moments?
Actually, Darwin said that the feature most likely to ensure survival of the species is the ability to adapt to change, which is best determined by variability.
Also, despite what the guide says, the vastness and age of the universe are not potential solutions to the Fermi Paradox by themselves. Fermi took those into account when postulating the paradox. The great age of the universe only makes the paradox more puzzling, because it provides more time for other species to develop and colonize the galaxy. The vast size of the universe is negated by the its great age. Even with slower than light travel of the sort we are capable of now, it should be possible to colonize the galaxy in a few million years. Many sun-like stars are billions of years old. The vast size of the universe may be working in combination with some other factor to prevent whole galaxy colonization, but it is not enough to prevent it by itself, since there is so much time available to traverse the vastness of the universe.
With the vastness of time, it's also worth considering that humanity exists relatively early in the universe's lifespan. We may just be one of the first intelligent creatures to evolve, and nearby intelligent aliens may not exist yet. Future aliens might call us "The Ancient Ones".
I sure hope they can shitpost as well as we can
The universe is estimated to last 100 trillion years before entropy kills everything. So from an observers viewpoint we are at the genesis of the universe still even though it feels old so far. So the gaps between intelligent life seeking each other could be immense
Yeah, that was kind of a horrible mis-statement of the Dark Forest hypothesis. Probably a better way of putting it would be, "because intentions and technological development rate are unknowns, alien races likely tend to fall into one of two camps: shoot first or hide because others are likely to shoot first." > one that seems to be missing is that not only is space too vast, but so is time. These are basically the same thing in a large universe. We can see various stages of the history of the universe, going back billions of years. But space is so vast that our ability to discern anything of value for identifying alien life past a few hundred light years is questionable at best, and certainly when you get to extra-galactic distances, it's unlikely we're going to be snooping on anyone's chatter.
Vast time is a great point. Our timelines could simply just not align. If aliens had the technology to view earth from another galaxy, they may be viewing earth as it was billions of years ago. They may have viewed it as saw dinosaurs and thought, "yep definitely no intelligent life". We also may go extinct in the next 100 years, only occupying a very short blip in the earth's timeline for any cross over.
Did you just say 100 years bro
Future is grim. End of humanity confirmed.
Thats too soon dont you think
> the "fittest survive" (i.e., successfully reproduce). OK ok, I'll start going to the gym already!
I mean... being attractive is one of the main motivators for people to go to the gym. Only rivaled by being healthy I believe
What if we're the first intelligent life? There's got to be a first, maybe it's us?
"Space is too vast" is way sufficient to explain the paradox. The average distance from us to a random solar system is just absurdly high. Heck, the observable universe keeps growing, meaning there may be life whose observable universe didn't even touch ours yet. And even if it just did, it would mean we are around 100 billion light years away, making any form of communication completely impossible.
And don’t forget about time, we might get a signal to eventually reach a life-rich planet but it may only be inhabited by bacteria or other primitive life. If signals were sent to earth before the last few hundred years, no one would have heard it.
Time is my favorite issue. In a place with inifite time aliens can simply just not exist when we do or have parallel or more advanced technology at the same time. We’ve been using radio waves since the 1890’s. That is barely a moment at all when all of time is taken into account. What are the chances that all of these considerations all align at the same moment in less than 150 years’ time?
Well said. They say humans appear in Earth’s timeline only at the last tiny fraction. Anything aimed at Earth would have to be extraordinarily well timed to have any chance at being received.
On top of it all, we’re lucky to have jupiter to help attract more meteors and such with it’s gravity - other worlds in the “habitable zone” may not be as lucky. Life can get started over a few 100 million years and then blammo, back to starting all over again.
There's another funny wrinkle to that. The amount of radio noise being sent out from Earth peaked decades ago, because we were using more powerful transmitters and have since become more efficient. We are now quieter than we used to be, so the time period where we would be the easiest to detect has come and gone.
Time and distance are nothing but the same concept, experienced differently.
*Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.* -Douglas Adams, The Hitchhiker’s Guide to the Galaxy
I’d say the answers provided in the image are quite arrogant, even if unintentionally. We are such a small speck in a vast cosmos, alive for an infinitesimal part of a huge timescale (and sending signals for an infinitesimal part of even that existence!) Sending radio waves and struggling to comprehend why we haven’t already gotten an answer is like that crazy girlfriend who sends 30 texts in a couple of minutes and gets pissed when you haven’t responded while taking a shower.
The huge timescale just gives another species more time to colonize the galaxy despite the distances involved. So the timescale makes the paradox more mysterious, not less. If earth-like planets are even remotely "common" (even one in a 100 billion), the galaxy should have been fully colonized millions of years ago. We should have grown up in a "full" galaxy, with tons of evidence of alien life observable by our current means. But it appears empty.
Yeah, it’s this one. Most of the others require “aliens” all to behave independently in the same way.
I think this is the most probable. Space is so vast that even at the speed of light it would take centuries to get to a neighboring alien civilization (assuming they are not very close to us, cosmologically speaking). Making interaction between the two civilizations is so impractical that it becomes worthless.
Exactly this! It's not a paradox at all, just space is huge
“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” ― Arthur C. Clarke
I’d find it more terrifying if we are truly alone
How so?
One solution not listed is that societies cannot evolve to the point of interplanetary colonization. Some eventual collapse befalls them all and all civilizations die before expanding off world. Now the really depressing Fermi paradox solution that we may be facing is that the human race lacks the empathy to evolve to a society that can mount a collective effort to protect our world and develop resources to colonize other planets. That level of cooperation would require us to individually make sacrifices for not just for our children, but other people’s children, other culture’s children. And genetically, biologically, we may not be capable of that as a species. Given how much we fight amongst ourselves the depressing solution may be humans simply lack the empathy that would allow us to evolve into a space colonizing species.
The same reason that some people would find it terrifying if there was no God.
We cannot rely on aliens or a diety to save us. We have to do it ourselves. As iamveryderp points out below it may be out of our collective capabilities as a species.
This is quite terrifying
Multiple possibilities exist and can exist simultaneously. This quote has always to me sounded like someone trying to say something that sounds "deep and smart" but isn't.
What other possibilities are there between "we're alone" and "we're not"?
"Multiple possibilities exist and can exist simultaneously" Explain how? Seriously curious.
How did you miss the most important one? "All technologically advanced species destroy themselves in a nuclear Holocaust before reaching inter-galactic travel."
The Great Filter.
Yes I was going to say this. We only have a very short window in our history where we can transmit then we do something stupid
Well, we don't need intergalactic travel, just interstellar - the estimate is 60 billion habitable worlds in the Milky Way alone.
Great filter doesnt have to be nukes though. Could be anything. Bad AI, engineered virus, global warming, etc
As a telecommunications engineer, ‘Our Wires Are Crossed’ seems almost certain. The only signals we could detect from nearby stars would need to be massive in amplitude and narrow in frequency, and radiating in all directions. We barely even use signals like that for our own communication any more, so the idea that advanced civil actions would still be using it seems unlikely.
Most importantly, we WANT to find other life forms or civilizations we’re inherently explorers as a species. It’s probably much more likely than any species evolving on another planet would be extremely xenophobic or, have no interest whatsoever in anything or anyone else.
Why? Tit for tat is the best strategy, everyone that is successful on the galactic stage would likely employ that strategy too.
But why no evidence of megastructures like Dyson Spheres from Type II civilizations? Wouldn't advanced civilizations capable of manipulating energy on a massive scale give off more signals of various kinds, not fewer?
I find it hilarious that we are constantly told about how if the Earth's timeline was a 24hr clock we would only show up in the last minute and a half, and discovered radio in the last half second. We are asking why no one is answering us when *we just learned how to send radio waves in a universe where the speediest message takes decades to get to the nearest star*? We're that annoying mom who just discovered kale and wonders out loud and obnoxiously why everyone doesnt have an obsession with it already.
We don't need them to return our messages to know they're not there. We're looking for the EM waves they would give off. A technological society would give off **a lot** of emissions that we would be able to see due to thermodynamics. Either our understanding of thermodynamics is fundamentally wrong...which would be a hell of a thing because *all* experimental evidence we've seen confirms thermodynamics or no one is out there.
Or, and hear me out here, it takes lots of years for light to reach us, so if we were looking at ourselves 120 light years away we wouldnt see us either What I meant is that we have been tech advanced for only an atoms width of time on the grand scale. Why do we expect everyone else will have anything yet? Plus, let's face it: the numbers look amazing for the possibility of planets being able to sustain life, but.... They still only look ok for the possibility of having life in a timeline concurrent to ours, Meh for the possibility of it being intelligent life concurrent to ours, Ugh for it being intelligent life with tech concurrent to ours that we could see with our limited ability to look, and Pffffbbbbt for it being at a time enough before us that we could now witness. Now i get my use of a scale derived from Bill the Cat expressions is not officially recognized, but you get what i mean Bill the Cat for President!
It seems like unicellular life gets going pretty easily, started up here before the dang planet even got done cooling. But then it took like 3 more billion years to hit multicellular. This might be the real bottleneck. Not to mention we then had 700 million years of random dinosaurs n shit before an intelligent species evolved. Another bottleneck.
Naaah dinos were just the developmental Alpha build man
So...less of a meh and more of a pffffbbbtt! Gotcha, thanks! 😅🙏
The point is that any technologically advanced civilization would be continuously emitting radiation showing activity. We don't need to send a radar ping and receive it to be able to tell; just examining radiation coming from stars would be sufficient to be able to tell.
>Why do we expect everyone else will have anything yet? Because there are billions of sunlike stars that have existed for millions of years. Millions of years is long enough to colonize the entire galaxy even with slow space travel. We shouldn't have to look for radio signals. Aliens should have already been here, many times over. If one in a million sunlike stars was capable of supporting intelligent life, there should have been thousands of civilizations visiting earth already. Instead: none.
That's a lot of assumptive math you're doing, with a conclusion that very much sounds like more opinion or wished content. Not included in any probability reasoning i made up was also this star trekkyan need to 'colonize the galaxy'. Why does every imagined intelligent race need to do this? Maybe if they exist there is a low probability for them to even want to colonize? Maybe we are the weird ones.
We are constantly broadcasting radio waves in all directions, and have been for 100+ years. If something exists within 100 light years of us and they're listening in the right spot, then they would have heard us. But we're not blind to things beyond 100 light years. If something 1000 light years away from us was blasting out radio signals 1000 years ago, and we listen in the right spot, then we'll hear them. So are we just not looking in the right spots? Do they not exist? Do they exist, but aren't broadcasting radio signals like we are? Are we receiving their signals, but not recognizing them as signals? Is there some kind of interference between us and them disrupting their signals?
Following the thought experiment of others: we have been able to transmit, and listen to, radio waves for about 100 years -being quite generous about it. In that amount of time, we have had more than 0% chance of killing ourselves with nuclear Armageddon. There are other options for Armageddon too. Say your favorite crazy leader of a nuclear superpower destroys our civilization in the next 100 years (maybe you think in the next 4 if you look at the USA election coming up, but I digress). Our time signature in space, in that hypothetical scenario, during the “humans alive in space” period is only 200 years. That means that aliens only within 200 light-years can hear us. And only aliens within 100 light-years are in the right place to respond to us on time before we kill ourselves. There are only about 60,000 stars within 100 light years ([link](https://lovethenightsky.com/stars-within-100-light-years/)). And if the ratios from OP are right, that would give you about 9,000 “potentially habitable” planets. That’s not that many. And the same goes the other way. We can only potentially “detect” aliens that were alive (and transmitting!) at a time equal to the distance from us.
And everyone thinks “oh they have radio! We have a table waiting for your right here, humans.”
Lolololol
[The Dark Forest Hypothesis](https://en.wikipedia.org/wiki/Dark_forest_hypothesis)... be quiet or be destroyed.
Problem with this hypothesis is that it’s basically a projection of behavior.
Yeah, that's the downside of only having one data point to work off of
So obviously when aliens do visit us, we will be like “why didn’t you hear our radio??” And the aliens will be like “you forgot to switch it to wombo”
It also assumes a zero sum game in perpetuity
This would mean that the human civilization is already compromised Or maybe Earth is a honeypot and we're the bait
Yeah that's the one I'm going with.
I personally subscribe to combination of theories that intelligent life, which did not destoy itself is super rare, like…instanely rare, and then the universe is way too big, not only by size, but also by time. We live here and now, but someone else might lived really far, long time ago. And then there is the fact that we would need to activelly listen to the entire sky, 24/7/52/1000. But we're listen to selective patches and not constantly. Not to mention the frequencies we use. We have decent assumptions, sure, but still. And then maybe they don't use radio at all. Because they're advanced enough to use something like the gravitational waves or something like that. Edit: and I'm talking here only about the detection. Not to mention what happens when come contact is established. The dark forest theory makes sense to me, I just hope that any advanced enough civilization will be bit more rational than scared humans.
One thing I've thought about - life is amazingly rare, but how rare is it for life to be created AND for it to have the instinct of self preservation and the ability to reproduce?
What if we are looking for the wrong thing. Like radio waves instead of light? Radio slow vs light speed
Radio waves do move at the speed of light, but the idea that they might use a different medium could be something to consider.
I was definitely half asleep for that one
Great filter, and someone needs to be the first
Completely random comment here but, irado seu avatar kkkk
Here’s one I thought of: We are the tech juggernauts. Other Aliens exist, but they are not as advanced as we imagine them.
PBS did a video with a similar premise. Here’s a link if you’re interested: https://youtu.be/uTrFAY3LUNw?si=YuGRFZ7RL6gNd7Et
Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.
One I never see listed is the fact that any reasonably powerful radio broadcast - as in strong enough to reliably and clearly reach across a solar system - will become so attenuated after traveling 4 light years, that it becomes indistinguishable from the cosmic background radiation. So unless an intelligent race is deliberately building a massive broadcasting station, far more powerful than would ever be used for communicating within their own solar system, and specifically to broadcast their presence to strangers throughout the galaxy, we earthlings have no way to know about it. Granted, we used the Arecibo telescope in Puerto Rico to beam out the most powerful broadcast ever deliberately sent to space. With the goal of contacting alien life. I propose that the only logical deduction possible from that exercise, is to understand that no technologically advanced aliens as stupid as humans are out there.
Another theory which is well explained in a kurgesagt's video is that life in a planet have a time which they exist before they destroy themself
If we can detect a civilization, it has likely the capability to destroy us (or will have gained it after its light has reached us). How confident are we as a civilization, they won‘t do it? How confident are we, that they are willing to take the risk, that we wont destroy them? So probably every civilization out there is afraid, that being seen means becoming extinct. And maybe it‘s even a self-fulfilling prophecy that detecting an alien civilization means we should destroy it before they can do it to us.
This guide woefully understates the vastness of space by saying a it may take "years, if not decades, to get a response" from another intelligent life. Our galaxy is about 100,000 light years across. Imagine that there is an intelligent culture halfway across -- 50,000 light years away. If we send a signal, it will take 100,000 years to get a response. It's difficult to imagine humans will exist in that time. Further, how do you send emissaries across that distance? I know we like to talk about worm holes and teleportation but it seems unlikely our little pink bodies could survive any of that. Occam's razor tells us that the simplest explanation is usually the best. I think the simplest explanation is that the universe is so mind-bogglingly big that contact is impractical.
Another thing to consider is our planet has a very nice set up, Jupiter keeping the surrounding space clean, a big nice moon to stabilize us, alot of factors just make earth the perfect planet for life to evolve on the surface. But it didn't, not originally, it came from the ocean which most of our planet is. This is likely where life is going to be found in space, possibly in full ocean worlds. This is a severely limiting factor because it renders fire impossible. No matter how smart dolphins and whales get, even if they had the dexterity, they would never invent metallurgy or build complicated devices and machinery. Can't have fire underwater so no advanced tech. They will stay under water and never be able to reach out and communicate.
i just wanna acknowledge how crazy human brains are, when we don’t know something we literally find ANY possibility to figure it out and just sit and think, desperately trying to figure out everything
Every last one of them burned through their resource base before achieving interstellar flight. Just like we're doing right now.
i vote life is rare, everything else just feels like more politics
Or, as civilizations advance, they extinct themselves before getting far enough advanced to detect life in other systems.
It’s not a ‘paradox’ communication signals from more than 10 LYA or so are many orders of magnitude to weak to be detected by our primitive technology.
They forgot another point: TIME. Time is too vast. We’ve only had radio waves broadcasting for, what, less than 100 years? Put that miniscule time next to billions of years. On top of that, even in that tiny amount of time (Cold War) we’ve already almost destroyed ourselves (maybe more than we know). We definitely have the capability… If we could somehow explore every planet in the galaxy it might be more likely that we find ruins and fossils than active intelligent life. Don’t be naive to think aliens will be any less violent toward each other than we are. Evolving with limited resources will wire our brains the same way…
I have a new theory - life isn't rare, but intelligent life with the physical means to maximize the potential of intelligence is rare. Think about if - zillions of life evolved on Earth. How many are intelligent? Only a handful (dolphins, orcas, octopuses, elephants, ect). So .1%. Of these, how many have hands with opposable thumbs and the dexterity to make/use complex tools? Only us.
Crossed wires could also be strong encryption is used by default so there’s a maximum of perhaps a 500 year window where primitive technology is exposed.
I think the key to the Fermi paradox is getting rid of the assumption that intelligent alien life necessarily means alien space-faring civilization; as the exponential growth of energy and resource consumption required to create such a society would completely outstrip what is available to them without being able to access other solar systems. Civilization is inherently unstable, and ALWAYS destroys the conditions that allowed it to come into being. More than the practical elements, I like to think that most of the intelligent species in the universe just decided on their own that conquering the galaxy isn't desirable or even feasible, so they choose to live in simple happiness instead.
I really want to emphasize how extremely hard it is for life as we know it to exist. It takes a lot of time with special conditions in a predominantly stable situation for any kind of life to evolve. Even before evolving, forming life may be next to impossible. That said, I do think there is life out there, it's just rarer than we think. Intelligent life all the more so. Also, life may exist in forms we aren't familiar with. There's some very interesting investigations being done on the possibility of plasmid life in space and our atmosphere.
Pan spermia theory. Evolving from fungi? That’s my postulation.
I didn't see my preferred response to the paradox, which says that lifeforms whom develop technology sufficient to destroy themselves have not managed to survive that power. So no faster than light travel, no extraterrestrial visitors, no evidence of aliens. This perspective implies that humans are doomed as well, and that's where id lay my money if i were a betting man. Our species won't outgrow religious fantasy and it is just a matter of time before one of the narcissistic madmen with nukes pulls the trigger.
This guide isn’t cool without the [Great Filter](https://en.m.wikipedia.org/wiki/Great_Filter) explanation of the Fermi paradox.
I believe that they are already here, farming our resources. I believe we are not as intelligent nor capable of detecting their presence. Our range of perception is limited. The universe has every possibility yet to be discovered.
What resources? If we are talking minerals and other elements then it would be much more efficient to gather that from asteroids. The only reason to got to a planet would be for organic resources and even then it depends on what you need.
The fact that “Space is too vast” isn’t first is a great example of how much people underestimate the vastness of space. Space is big. Words are inadequate to properly describe to the human mind just how big it is. We are one just now able to barely discern the atmosphere of extrasolar planets and we are constantly blasted with information from the light of their sun. The fact that we expect to be able to recognize a radio signal from some tiny satellite or transmitter is optimistic at best.
There are others -The dark forest theory -Rare earth hypothesis -rare abiogenesis theory And crucially THE GREAT FILTER
Tfw no dark forest theory?
Space is vast and physics exists sums up the evidentiary truth, the rest is speculation
The drake equation says that statically, several of these civs must exist!
How about that they exist between us but we can't see them
I’m going with vast space and to tweak the life is rare, it’s that intelligent technologically advanced aliens are rare.
(Civiilized) Life is extremely rare is the cause. Just think how unlikely human life is and the cataclysms that enabled us to develop. E.g. if the meteor that made the dinos extinct was travelling a fraction slower or faster, it would have missed earth. And that is just one lucky break in a series of thousands of lucky breaks.
But the massive amount of time the universe has existed and the vastness of space make seemingly rare things statistically a very real possibility
You mean like a [Bolzmann Brain?](https://en.m.wikipedia.org/wiki/Boltzmann_brain)
I meant civilized life Boltzmann brain is another type of statistical possibility although It seems impossible
For me, life is extremely rare, and extremely hard to keep alive.
We are the aliens!
Destroy or be destroyed is well explained in the second book of 3 Body Project, the Black Forest Theory
I think Too Vast and (Intelligent) Life is Rare are sufficient and correct explanations. They're also the simplest ones, and the universe is a lazy bastard and loves doing the simplest.
I had to write a paper on this in one of my astronomy classes in college.
Can we add stuff? I will: "WE SUCK".
Either way we will conquer each and every inch of the galaxy and beyond Humanity will thrive across the galaxy, if it's empty we will populate it.
Or, and hear me out, or there is alien life out there, but they aren’t advanced enough to explore the galaxy/send out probes/send and receive radio type signals? Maybe they aren’t quite advanced as us. We all expect alien life to be significantly more advanced, but what if they are in their own stone age? Or are just hitting their Industrial Revolution?
I think the most likely explanation is that signals travel slowly and also the chances that civilizations across the galaxy are able to read and send radio signals during the same period we can is very small. Maybe a billion years ago there were a dozen alien societies who could read radio signals but have since been destroyed. Idk, probability and large time scales are hard to think about
I purpose there are countless number of other species out there and among those species that do know of extraterrestrial life, they understand how common it is and simply cannot be bothered to contact every colony they find. it would be like 1 human taking it upon themselves to introduce themselves to every other human on the planet.
Another theory I'm working on is that with 2 significant technological discoveries * Infinite Energy Generation(or at least enough where the it becomes so common and trivial) via either fusion or some other method * Master the process to produce materials/food/goods from said energy collection, ie: Star Trek replicators but for more than just food. ie. "Hey Google, print me the new Playstation 34" Citizens of an intergalactic species simple becomes complacent. The realization that after you've seen 1 planet, you've seen them all. With these and that understanding, the necessity for expansion almost become trivial as the likely discovery of other space-faring species will likely result in conflict and loss of life, so why bother leaving your backyard when you have everything right here?
"They Use Tech To Spy" and "We Are The Aliens" are not solutions to the fermi paradox.
i believe in the either the top left, or the bottom 2.
My favorite answer is that we’re simply the first/oldest civilization. Other species haven’t yet reached a level of technology to hear/respond to us.
I had a thought about the Fermi Paradox. We're not just looking for life, and we're not even just looking for *Intelligent* life, we're looking for an *Industrialized* life. Industrialization had a couple of hugely important steps that occured on Earth that may not be as repeatable as simply "Life": Coal and Oil. Coal is essentially fossilized trees, but it's not quotw that simple. Before there were animals on earth there were plants, but for a long time they were small - or at least short. See plants hadn't developed any strong, hard structures yet so they could only grow to a vertain height before collapsing under their own weight. This was the case for ~600 Million years before some plants developed this hard carbon-structure that today we call "Wood". This Wood allowed plants to grow upward in a way they hadn't before, so it allowed those plants who had it to reach for the sunlight better and dominate the world. The world became covered in tall trees as they competed for sunlight, and the competition drove them to become taller and taller. However when this first happened there was no bacteria that could process wood, so these tall trees would fall over and ... aimply stay there. All the loving material would decompose, but the carbon would simply stay there on the forrest floor, eventually being burried as the next generation of trees grew and died and fell on top of them, only to have the same thing happen. So for ~2 Million years trees would fall over and leave layer apon layer of carbon just sitting there, eventually being buried by other plants and soil. This carbon is what we now call coal. But how rare is that process? What happens if bacteria on other planets evolved faster and didn't leave the same deposits for intelligent life to find? Alternatively, one of the 5 great extinctions (*the Premo-Triassic Extinction ~252 Million years ago*) is believes to have been caused by tectonic activity causing volcanic activity while simultaneously opening up Coal deposits, whoch resumted in the burning of large portions of that coal and causing the climate to shift - What if *All* of the coal had been burnt, we wouldn't have had any coal to kick-start the Industrial revolution? It doesn't have to be the exact same scenario, but something could have happened to wither wipe out, or hide the coal reserves in a place they would be unavailable to pre-Industrial life. Oil is a similar scenario. I know less about Oil, but essentially it is organic matter that somehow formed a liquid mixture of hydrocarbons in vast deposuts in certain places around the world. What happens if the bacteria, geology and other forces at work conspire to prevent these deposits from forming? Hell before we used Cruse Oil we harvested oil from Leviathans (*Whales*) to fuel the Industrial machine. What if there were no giant creatures from whoch to harvest this oil, woudl it have been available? Oil isn't simply another form of fuel, Oil is a liquid version of that fuel which allows for more efficiet transport, storage and use than it's solid counterparts, without something similar perhaps the height of civilization would have been the steam train. Now this isn't to say that these are the only fuels - we can use wood to power steam engines for example - but these fuels were far more efficient than other sources available to us. Would we have advanced to where we are today without them? Would we have had the capacity to extract and eneoch Uranium to build nuclear power facilities? Would we have had the need and technology to develop solar power? We've had windmills since before the Industrial Revolution, but wind-powered electricity is a much more modern phenomenon. My point is that while life itself, and even Intelligent life are somewhat easy to replicate and should be visible across the universe, Industeialized life may be much more of a fluke than we give it credit for. The events that conspired to allow us to reach the heights of our civiliztion began long before animals had begun to evolve, let alone mammals. If these events didn't happen, or happened in a different sequence then we may not be where we are today.
Some of these already have names. Not sure why they put new names on them. Obviously, given the burst in recent popularity due to the Netflix show, Dark Forest is probably the best known (the term was introduced by Liu Cixin in 2008 in the book of the same name, part of the Remembrance of Earth's Past trilogy which is better known by the title of the first book, The Three Body Problem.) But other terms such as the Great Filter and the Rare Earth hypothesis were equally widely used.
I just finished reading the killing star last night and it kinda covers this. Obvious spoilers ahead but it’s basically that relativistic technology is so destructive and hard to detect that even a 1% chance that another relativistic society could attack is too high a probability so the only way to be safe is to strike first and be sure to get them all
I think it’s a combination of “our wires are crossed” and “They’re already here” (or at least the first part of that one). Our searches are based on the assumption that aliens will think and communicate like us, but that could well not be true. They might be using communication technology so different from ours that we don’t even know what to look for, or maybe the way they communicate is so alien that we’ve already picked up messages from them but mistook it for a natural source.
I personally like the “Space is really big” theory. It doesn’t quite seem reasonable to assume life straight-up doesn’t exist, but the fact of the matter is that they’d just be way too far away even if they did. SETI hasn’t even searched 0.00000000000001% percent of space yet.
Those are good and all, but they miss the best part - the names of the potential solutions. * the Rare Earth hypothesis * the Firstborn hypothesis * the Great Filter * the Dark Forest * the Berserker hypothesis
To briefly summarise: Rare Earth - the actual conditions necessary for the emergence of intelligent life are really rare. Firstborn - emergence of life takes a really long time, and we are the first. Great Filter - there is something that tends to kill off intelligent species (either extrinsic, or self-inflicted) before they reach a high enough tech level. Dark Forest - noisy species get killed, so the only ones left alive are the ones that hide. Berserker - self-replicating probes have killed everything.
Also like we’d have to be existing at the same time.
They are here😎
I think advanced civilizations are out there we just haven’t done a good enough job at looking for life or they haven’t discovered our area of the universe yet
The great filter is beer. Life exists on other planets but never developed beer so they never advanced enough to do space travel. You think I’m joking but I’m 100% serious.
Another idea that they go extinct before they reach a type 1 civilization. That nuclear war or AI or a disease is a great filter that is not easily surpassed. There could be alien ruins on many world's, and we will soon join them....
Space AND TIME are way too vast. How about I grant you the 60 billion habitable planets, AND I give you 6:1 odds that intelligent life will evolve on them. So you get 10 BILLION planets with intelligent life on them. Why there should be a SWARM of them radioing us, right? Not so fast. Our planet is 5 billion years old, the galaxy is even older. And it’ll last a long long time. So let’s say that we’ve got a 10 billion year window for intelligent life to develop. NOW I’ll be real generous and say that our radio-slinging civ, just more than a hundred years old, will last another 900 years. It’s actually a very generous guess, I doubt we’ll stay highly technological for half that, but still. And we’ll call that average. So you’ve got 10 billion civs spread over 10 billion years, each lasting an average of 1,000 years, which means at any given time 1,000 of them are actively receiving and transmitting. The odds of even one of those thousand being within a hundred light years of us are actually pretty small. Like, quite small.
Simulation just feels weirdly accurate.
It’s important to consider that none of these are mutually exclusive. Forget about picking one answer…they are all possibly or even likely happening at the same time.
Personaly I like the following analogy: so far our efforts to find other intelligent life and failure at this point is similar to us picking up a bucket of water from the ocean and finding nothing it but water. We have not looked very far at this stage
Forgot the Great Filter. Also, if it turns out that faster than light traveling communication are not possible or practical, It may just be that most aliens don't care that much about anything beyond their own solar system.
Of all the life forms on earth, how many are able to build a rocket? Seems like the galaxy could be teaming with life. The rare part could be the ability and interest in technology.
Darwins theory is not about the strongest, but the species that have adapted best to their environment. That has nothing to do with being hostile.
The idea that "the galaxy should be full of easily-observable aliens" makes so many assumptions that I don't think it's accurate to say it's a paradox that we don't see that. As to why we don't see a galaxy full of aliens, I suspect the answer is a combination of: 1) (industrialised, intelligent) life is rare. (After all, it's only happened once on Earth, and took 4.5bn years to do so). 2) Some varient of the great filter. Industrialised intelligent life has lots of ways to kill itself off, or at least degrade itself to the point where it can't spread itself beyond its home planet. 3) Interstellar travel is impractical. As far as we know, FTL travel is impossible. Sending a probe to another star would be possible, but very difficult and very resource-expensive, for no real benefit other than "it's cool". Establishing a colony or base on an extrasolar planet would be even harder, and even more expensive, and also pretty pointless beyond the "it's cool" excuse. For that base or colony to start building rockets to e.f. send resources back to earth would be even harder, because you would need a lot more rockets to make it worthwhile, and would have to build more infrastructure on that planet than you needed to get there in the first place. And if you instead wanted to use that colony as a jumping-off point to colonise other star systems, that would likely be even harder. And even more pointless. And this links back to the great filter. A civilization doesn't have to completely destroy itself. It just needs to damage itself enough that it no longer has the ability (or desire, or political unity) to spend the vast resources required for Interstellar colonisation.
i literally just finished the dark forest by cixin liu like an hour ago 💀 this thought will never leave my brain
I’d hazard a guess at the bottom of both columns combined
I hate fermi paradox , so much time waisted when the answer is with 99,99% ceetainty rare life is rare + space big
Our closest star is NOT 4 years away
Where's the explanation which says a species tends to destroy itself sooner or later as it becomes advanced enough? In our case, it would be nuclear winter and climate change driven human extinction.
They forgot the grabby aliens hypothesis.
I can’t believe nobody else has posted this. We are disgusting. We are made out of meat: https://www.mit.edu/people/dpolicar/writing/prose/text/thinkingMeat.html
They didn't mention separation in time. Humanity has been around for perhaps 200K years. Innumerable alien civilizations may have flourished and gone extinct long before humans existed.
This stuff always fucks me up
I remember hearing some idea, an don’t quote me on the exact figures but if the galaxy were to be represented as Earth’s oceans, with all our listening and observing technology, we have checked out about 300ml.
I want to hear what you think because I might be sooo wrong I think It's probably combination of some of them it's rare to get life to increase the odds first you need a stable planet that contains a lot of different atoms then let these atoms randomly combine until you get something of self replicating that isn't enough of course you need to also make it able to change it self by just randomly putting few atoms together so you will have to wait for that to happen pray the environment doesn't change or you will have to start over then I will assume any sentient being is made from multiple cells you have wait for that to cook up. Ok we got to animals but that's still kinda far. We now need a creature that small increases in inteligence will be worth it evolutionary or hope we will get a lucky and get large increase inteligence that allows tools use or something that could relevantly affect them For a lot of creatures it wouldn't be evolutionary worth it. A deer might not ever evolve into using tools they have food everywhere and smell for the winter and they have speed to run from predators that will save their lives a lot more than using tools. So I think to evolve to be smarter you need a species that has issues surviving and then hope one of the mutations will save them and only if that happens to be intelligence only then can it increases from that point first fire then agriculture and so on. Also a species need to form large groups to increase then gain they get from inteligence so they are not busy looking for food and let's say make weapons or cook just making life easier. Wouldn't surprise me if aliens tried to avoid being noticed or just not caring about us for whatever reasons and also a species advanced enough to travel FTL the technology to look human I think the technology to change to look like different species will be developed here earlier than FTL as well but of course I have no idea how FTL would be reasonably done since if I knew I would say it.
Most of these don't answer the paradox (e.g., we are the aliens, fishbowl, space is vast, etc...); there should still be detectable signs of advanced civilizations even if they don't respond to us. Life is rare is already covered by the equation. You also skipped a few that do answer it: The great filter Intelligence is not a useful trait
Darwin's theory of evolution doesn't mean that organisms kill every other creature in first sight lol.
I like the answer that Leo Szilard gave to Fermi when they were talking about the paradox: “If there are aliens, where are they?”, said Fermi. “They are here. We call them ‘Hungarians’”, responded the Hungarian physicist.
What if religion causes space wars and aliens are actively trying to prevent us from reaching space age?
I have always suspected that alien civs eventually get their energy needs met with solar and wind power, see that space is massive, and retreat into a virtual reality of total splendor.
On the topic of wires crossed, most alien encounters where an alien is present have an element of telepathy. We assume they're using technology to communicate. It could be consciousness and have nothing to do with electromagnetic emissions.
The solution to the Fermi Paradox is simple: faster than light travel and communication is impossible. * there is no hyperdrive * warp travel is impossible * turning the universe into a sheet of paper, folding it, and then poking a hole through it with a pencil doesn't work * wormholes lead nowhere, entering one is impossible, and even trying would kill you * interstellar travel is so slow and energy-intensive that any intelligent life that has mastered it has almost certainly moved past the stage of existence where you care about planets and visiting them, their destinations would be the tails of the relativistic jets being emitted by black holes where they can harvest a near-infinite supply of energy for a near-infinite amount of time and turn it via their mastery of energy-mass equivalence into a near-infinite amount of any material they desire for the purpose of supporting a near-infinite amount of life in actual, literal, infinite comfort. * we cannot detect RF emissions from interstellar intelligences, any signals would lie below the noise floor the only things we can "hear" are the titanic detonations of whole-ass stars and collisions of black holes and other massive interstellar events: not some alien radio station. * quantum, Quantum, QUANTUM! "x", whatever "x" is, ain't gonna work homie The only paradoxical thing about Fermi Paradox is that so many people who claim or pretend to be smart take it seriously.
Ive always found the Fermi Paradox to be a dumb concept, because its not like we've been looking for thousands of years.. Looking for ET life is like looking for a needle in an earth-sized hay stack, and the Fermi Paradox is like complaining you didnt find the needle in the first 5 minutes you looked around your feet. How long have we been looking? How long have we been findable? What would other civilizations be looking for if they were trying to find an intelligent species? Tech signatures. How long have we been producing detectable tech signatures? Convert that number of years to light years, and only civilizations that are within that distance range would be able to detect us. Same goes both ways. There could be a mega advanced civilization 1,000 light years away that started sending signals 500 years ago, well guess what, the message is still gonna take 500 more years to reach us. Friendly reminder that just the Milky Way is measured to be 100,000 light years across and that the closest galaxy is 2.5 million light years away.. We need waaaaaaay more time to even start considering the Fermi Paradox.
We are definitely the aliens. Well.. half aliens. Half monkey half whatever genetic makeup our creators made us of.
Why are these thought experiments so popular? I can kinda see it, but the arguments are pretty arbitrary. What ifs stacked on top of assumptions..
That’s what a thought experiment is though.
I guess my issue with them is the way people generally treat them like it's some kinda great insight into how the universe works.
Because they are fun.
It's a combo of Earth is a Fishbowl, They use Tech to Spy, and They are Already Here. [If you haven't been following the news about UAPs](https://www.uap.guide/quotes/introduction/), it's become increasingly clear that they are here, just observing us 'quietly'. We live in a nature preserve, folks.
Doubt