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The Milky Way is probably full of dead civilizations
- thomassmith65 11mo agoIt seems equally likely to me that conditions in the Universe just weren't amenable to life until relatively recently. Radio waves take time to travel; there could be many civilisations out there whose signals haven't had time to reach us. If that's the case, we're just the first intelligent civilisation to evolve in our immediate vicinity.
- pols45 11mo agoNot really. Microbes have been around for a long time. And there are more of them today than there are stars in the sky. No intelligence required. Plus they change so fast that what Life looked like yday can look totally different tomorrow. As Lynn Margulis would say the chimps aren't the main show. Intelligence maybe an over rated and very buggy feature of Life. And the bugs get amplified as the minds interact with each other and group size increases. The philosophers have talked about the bugs for a long time (see Plato's chariot, Hobbes passion vs reason, Freuds id-ego-superego, Kahnemann's system 1 vs system 2, Haidt's Elephant Rider). The mind needs stories to handle the bugs. And there is no dearth of stories on Earth to keep the 3 inch chimp brain occupied forever.
- thomassmith65 11mo agoIf that's the case, we're just the first intelligent civilisation or civilisation of radio-wave-emitting bugs to evolve in our immediate vicinity. :)
- nandomrumber 11mo agoNeutrino sources outside of stars / stellar-like objects would be a dead giveaway of either unexplained physics or nuclear fusion / fission technology, and much harder / impossible to hide than EM tech. We should look for those.
- OgsyedIE 11mo agoAll of the evidence we have suggests that the mitochondria-archaea endosymbiosis event that created the eukaryotes has happened only once in our entire history. If there were no eukaryotes, there'd likely be no way of getting past the energy per gene ceiling that constrains the other two domains of life.
- ahazred8ta 11mo ago"The anthropologists got it wrong when they named our species Homo sapiens ... In reality, we are Pan narrans, the storytelling chimpanzee." ― Terry Pratchett
- vikingerik 11mo agoThis isn't likely. The Milky Way is 100k light years in diameter. That's tiny relative to the age of life. Animals comparable to humans in complexity have existed for something like 250 million years on Earth, and could have on planets of stars that formed billions of years before our sun. The possible timespan for signal-emitting life to have developed is many multiples of the timespan that signals take to cross the galaxy. It's far more likely that signal-emitting life is so rare (or short-lived) so that they are separated by distances where their signals weaken to undetectability, than that we are the one fantastically lucky star to be the first among a hundred billion. Star Trek showing all the rival civilizations exploring the galaxy at the same time makes no sense at all. It's far more likely that civilizations would arise separated by time of millions or billions of years, than that they would all be concentrated within a few centuries. (Trek does hint strongly that the explanation is panspermia, that life was seeded everywhere at the same time to account for the time-concentrated development.) What we don't know is what makes signal-emitting civilizations cease to do so. But (if we aren't the fantastically unlikely first one) either something must, or they're so far apart that signals can't be detected between them.
- thomassmith65 11mo agoThe radius of the observable universe is 45.7 billion light-years. The universe is approximately 13.8 billion years old. Primates evolved only six million years ago. So let's be charitable and say it took only 13 billion years for a lifeform capable of transmitting radio waves to evolve. Unless I'm missing something, if we're listening for ETs, we would only have visibility into a sphere with a radius around 1/45th the radius of what is out there? My point is, if the Universe is such that it takes a minimum of, say, 10 billion years for planetary conditions to make evolution possible and evolution to wind up at intelligent life, then there could be hundreds or thousands of civilisations out there, at this very moment, whose earliest signals won't reach us for millions of years.
- vikingerik 11mo agoPrimates evolved six million years ago here. There are plenty of stars billions of years older than our sun (and still sufficiently enriched with heavy elements from prior stellar generations) where they could have, so that their signals would have reached us by now. The past light cone is everything you see in the sky. Even a million light-years from neighboring galaxies is small compared to the time scale of possibilities on the order of multiple billions of years.
- Madmallard 11mo agoIsn’t it likely that radio waves beyond a certain distance will just become indistinguishable from background noise? They’re travelling hundreds of thousands if not more light years
- toast0 11mo agoRadio waves beyond a certain level of sophistication may not be very obvioualy artificial either. AM vs FM vs QAM vs ??? Add spread spectrum and maybe more efficient radiator patterns / beam forming. I suspect we won't be emitting much that would be likely detectable after the end of this century, so maybe a 200 year window. I asusume other radio capable life would perform similarly. If that's the case, chances are slim that their 200 years of detectable emissions overlap our ability to detect the detectable.
- CheeseFromLidl 11mo agoFrom our 1 datapoint set I’m leaning towards the “earth is an aberration” theory. This was a dinosaur planet. There was a reset some time ago that cleared the path for mammals. It’s unlikely that this timing is common.
- Qem 11mo agoIt was recently proposed the hypothesis we suceeded at developing intelligence while dinosaurs failed because humans evolved under the lowest levels of atmospheric CO2 in the entire history of Earth, allowing brain upscaling, at least until we botched it in the last 2 centuries. See https://www.qeios.com/read/IKNUZU https://www.qeios.com/read/IKNUZU
- lm28469 11mo ago> It seems equally likely to me that conditions in the Universe just weren't amenable to life until relatively recently. It's at least 4b years old on earth, that's not "relatively recently" We've been technologically capable for less than 200 years, that's nothing in the grand scheme of things. We could have just missed them by a few millions years and we would have no ideas at all. There might be 10 ancient Egypt tier civilisations out there right now that might develop radio tech by the time we're extinct or back to low tech.
- amanaplanacanal 11mo agoLooks like a bullshit paper. This big question mark is: assuming life evolves on a suitable planet, what are the odds that something like an intelligent technological species would ever evolve? We only have one example: us. You can't extrapolate from that, so they just made up numbers.
- gregbot 11mo agoCorrect. Obviously no honest person can claim to have an objective way to quantify “intelligent creatures' tendency toward self-annihilation”
- kstrauser 11mo agoDefine "technological". We've recently accepted that there are several tool-using species other than us. We have a head start on other apes, but they might catch up if we weren't in the picture. If octopi stopped dying so young, they might give us a run for our money. Orcas have fashion trends ("did you see Becky's dead salmon hat? I'm getting one of those!"). Mess with corvids at your own risk.
- adrian_b 11mo agoFrom a technological point of view, the main distinctive feature of humans has not been the use of tools, which is relatively widespread among animals, but the control of fire. The control of fire is what has enabled humans to produce and use new classes of materials that all other living beings are unable to make, e.g. ceramics, metals, glasses, cements, thermoplastics and thermosets, various kinds of crystals, including semiconductors, etc. These materials have been essential in the development of human technology during the last twenty thousand years. All the other living beings can use only a limited range of materials, consisting of polymers that can be synthesized at ambient temperature and pressure (e.g. wood or horn or chitin), adhesives and the equivalent of sedimentary rocks (in various kinds of skeletons, most commonly made from composites of proteins or chitin with insoluble salts of calcium, strontium or barium, but also including those made of sedimentary glass, i.e. opal, like in sponges and diatoms). (Natural glass is either volcanic, made by rapid cooling, like most artificial glass, or sedimentary, i.e. opal deposited from a solution of silicic acid in water. Living beings can catalyze the latter reaction in order to make siliceous skeletons.) So the myth of Prometheus was actually quite wise in comparison with many later attempts to define essential features of humans. Any living beings that have remained confined to a water environment, like cephalopods, do not have any chance to develop a technology comparable to that of humans, because without being able to use fire they could not make metals and the other materials required for that. Being unable to create an advanced technology is not an obstacle to reaching a high intelligence, as high as that of humans. The humans of fifty thousand years ago were as intelligent as those of today (perhaps on average even more, as all the dumb ones died quickly), even if they did not have yet any technologies that could not have been developed by something like an octopus.
- excalibur 11mo ago(2020)
- sema4hacker 11mo agoIf the Milky Way is "full", imagine how many there are in the universe.
- micahcc 11mo agoWAG in WAG out
- Panzerschrek 11mo agoThis paper doesn't account the possibility of a civilization to spread itself and to fill eventually the whole galaxy. But in such case it's practically impossible for such civilization to extinct. Since we see no intelligent signatures everywhere, it's certain that no such civilization was formed in our galaxy.
- gizajob 11mo agoIt’s not really possible to say that it is certain given we haven’t looked very hard or for very long. We don’t even know if there’s life in nearby places like Enceladus.
- Panzerschrek 11mo agoWe don't need to look hard. If interstellar travel is possible and someone in our Galaxy have developed it in the past, the whole Solar System including Earth should be already colonized.
- gizajob 11mo agoThere are many other answers to why it isn’t outside of “they should have done this but haven’t and therefore cannot exist”.
- inkyoto 11mo agoWhat continues to vex me is the tedious inevitability with which hypothetical extraterrestrial civilisations are assessed through the narrow prism of human failings – namely, self-destruction and aggression. Intelligence, a term we are so fond of bandying about, encompasses a spectrum of attributes, yet it is fundamentally anchored in two core tenets: logic and reason. An entity truly in possession of such faculties would, by necessity, also cultivate the ability to prevent its own annihilation – or the obliteration of others – in the face of tension or conflict. This, naturally, is a lesson the species inhabiting this planet has yet to comprehend, let alone apply. It is hardly inconceivable that another world might offer an abundance of energy and materials so vast that the primitive notion of competition becomes irrelevant – an absence that would, I imagine, deeply offend the instincts of Earth’s more belligerent inhabitants. Unless humanity is prepared to extricate itself from its parochial assumptions and entertain the possibility of wildly divergent modes of existence, it is unlikely we shall ever encounter a species with whom a meaningful exchange is even possible. Worse still – though entirely within the realm of plausibility – we may one day confront a civilisation whose moral and ethical framework is so colossally alien to our own that the mere act of contact would not enlighten, but unsettle, fracture and shatter.
- imiric 11mo agoYou make several good points. I would push back on the idea that alien civilizations might somehow be more enlightened so as to avoid internal conflict altogether. Unless they were artificially designed by a creator who explicitly factored out these traits, they likely also evolved from primitive beginnings. If we know anything from our single sample of living organisms is that competition and survival play a key role in driving evolution. Even if their planet had ample resources for everyone—which can also be said about Earth—those resources might not be accessible to everyone equally. This would inevitably lead to hoarding, tribalism, and conflicts. Besides, physical resources aren't the only cause for conflict. If they're social creatures, relationships, hierarchies, and politics also play a role. So all of these things would be embedded in their organisms even after they've evolved to a technological civilization, just like they are in ours. Therefore it is not difficult to imagine that they would also struggle to balance their use of technology with their nature to distrust each other. I don't think this is a human-centrist viewpoint, but one we observe from nature itself. However limited that may be, it's the only place we can draw any kind of conclusions from. Thinking otherwise is interesting, but the realm of science fiction.
- d4rkn0d3z 11mo agoI read a paper a long while back that used purely numerical arguments to first show a common rate in the growth of complexity across biological and non-biological systems under similar conditions. It then plotted this exponential growth backwards in time, showing that life's origins were prior to the formation of earth by about 1.5 billion years. No guesswork, it was quite solid; the same math applied to human technology traces back to roughly its known start on earth. It was convincing that life is prolific in the universe but intellgent life took about 6-9 billion years to go from single cell to us.
- jiggawatts 11mo agoObligatory: https://xkcd.com/605/ https://xkcd.com/605/ That paper used a horribly faulty logical argument because it has been well known for quite a while that most of the time evolution is quite slow, but there are short bursts of rapid change. For example: https://en.wikipedia.org/wiki/Cambrian_explosion https://en.wikipedia.org/wiki/Cambrian_explosion See: https://en.wikipedia.org/wiki/Punctuated_equilibrium https://en.wikipedia.org/wiki/Punctuated_equilibrium
- d4rkn0d3z 11mo agoThe "obligatory" doesn't apply since that paper did not extrapolate. It would be the exact opposite. I'm pretty sure the issue you raise is averaged away quite neatly by the math.
- jiggawatts 11mo agoThey literally extrapolated backwards in time. Extending your data in time is extrapolation, whether that’s forward or backward!
- deleted 11mo ago[deleted]
- d4rkn0d3z 11mo agoHow do you think we determine the age of the universe? The age of rocks? Do you not accept carbon dating? You could call this technique "complexity dating". First you show there is exponential growth (or decay) occuring naturally. The actual changes occur randomly but the mean rate is fixed. Then you plot on log scale and voila you have complexity dated life itself. The only argument you can make against is that the laws of physics are somehow not constant, but I think everything froze out by the time molecules were forming. So in your cartoon, the bride can marry a random normally distributed number of husbands each time. We would determine the average rate of husband accretion. Then given the number of husbands at any time we could determine when the rapacious bride began marrying.
- peter_d_sherman 11mo agoMaybe the question to ask is: "Can advanced beings evolve beyond the need for civilization?" Future Star Trek episode: The crew arrives at what appears to be a completely lifeless planet, and sees the empty buildings of a futuristic city... Crew member: "These warlike people must have annihilated themselves... nuclear war with advanced energy devices that penetrate buildings with high energy radiation, that leave the buildings but destroy all life..." Beings in light bodies (who suddenly appear out of nowhere!): "No, it's totally cool -- all of us are still alive! We simply evolved beyond the need for civilization!" Dumbfounded crew member (whose sociologic theory about civilizational collapse is now proven utterly and completely wrong!): "Oh..." :-)
- fithisux 11mo agoThis is also true for our planet. No reason to spend money on searching "aliens" just look near Cuba.
- Balgair 11mo agoThe composition of the universe is: ~5% matter and energy. The stuff you and I, dollhouses, dogs, and sugarcubes are made up of. Of that about 99.9% of it is very hot stars. ~20% dark matter. This is currently under investigation, but really all we know about it is that it is incredibly sparse and falls down. ~75% dark energy. We know nearly nothing about it except that it falls up (?!) Point is, if there are other civilizations out there, and they have been existing for even a few thousand years longer than our has, a cosmic eyeblink, they are probably not just using matter and energy anymore. Heck, their understanding of physics is so much more than ours, even comparing us to Plato and them to Devoret is an insult.
- tim333 11mo agoI figure the odds are there is other life out there but it's really hard to go visit or communicate. In sci fi you engage warp drive and zap there but real world spacecraft may take centuries. The aliens are probably out there wasting time on social media and saying stuff like We wanted flying cars, instead we got 140 characters.