29 ms·

Odds of communicating with 36 other possible intelligent civilizations are small

78 points by imheretolearn 6y ago

joegibbs 6y ago
Why do they assume that an alien civilisation could only hold communication technology for a hundred years? Surely there’s nothing really holding them back from it unless they wiped themselves out, and is there any reason to believe that at least some of them couldn’t last for thousands or even millions of years?
- austincheney 6y ago
  > "The search for intelligent life is only expected to yield a positive observation if the average life-span of [communicating extra-terrestrial intelligence] within our Galaxy is 3,060 years. That is to say, our communicating civilization here on Earth will need to persist for 6,120 years beyond the advent of long-range radio technology (approximately 100 years ago) before we can expect a [search for extra-terrestrial intelligence] two-way communication." https://edition.cnn.com/2020/06/15/world/intelligent-civilizations-galaxy-scn-trnd/index.html https://edition.cnn.com/2020/06/15/world/intelligent-civiliz...
- bhaak 6y ago
  The problem with long lasting alien civilisations is that if they do exist, why aren't they here already? Colonizing the galaxy only takes a few millions years even with 0.1c. So far, we only have proof that civilisations can exist for at least several thousand years if you consider the Human civilisation. But so far, the data on civilisations capable of interstellar communication doesn't look too promising. The "unless they wiped themselves out" is the big question. Are we behind or in front of the Great Filter.
  - GuiA 6y ago
    By definition there has to be a first intergalactic civilization, if there is to be at least one. The universe is ~15B years old, and we expect it to keep forming stars (as good as any of a metric for “hospitable to life”) for another trillion years. In other words, we’re in the first percent or so of the lifespan of the universe. Doesn’t seem too crazy that if we start conquering the stars, we might be the first ever species to do so. (And if history is any indication, we’ll probably cause some sort of galactic global warming in the process, that all starfaring species after us will curse us for)
    - akiselev 6y ago
      > (And if history is any indication, we’ll probably cause some sort of galactic global warming in the process, that all starfaring species after us will curse us for) The only serious theoretical FTL paper (Alcubierre drive) I know of requires exotic matter (negative mass) or energy equivalents of entire planets so if we ever manage to build it, I think that's a fair bet. Another paper calculated that the space-time bubble created by the Alcubierre drive would capture radiation and particles along its path, creating a gamma ray burst at the destination in a large cone in the direction of travel. Meaning, we'd be sending deadly bursts of radiation all over the galaxy that would wipe out all carbon based life for tens or hundreds of light years every single jump. A rogue actor or a miscalculation could wipe out significant fractions of our own civilization.
  - bitcurious 6y ago
    > The problem with long lasting alien civilisations is that if they do exist, why aren't they here already? Colonizing the galaxy only takes a few millions years even with 0.1c The kind of colonization you’re describing requires exponential growth, but at least on Earth we’ve seen that birth rates dropping in developed nations.
    - pedrosorio 6y ago
      There is no evidence this will hold true in a colonization scenario.
    - adventured 6y ago
      Exponential growth doesn't inherently require population expansion. This would especially be true for a far more advanced civilization. You could dramatically amplify your colonization efforts with machines, reducing your need for traditional population expansion (productivity expansion in tandem with population contraction is exactly what we're going to see on Earth this century).
      - bitcurious 6y ago
        Without population growth you lose the motivation. Communication gets harder every time you add a star to your civilization, unless you somehow break the speed of light. Resource use is unlikely to be a motivator - a civilization sufficiently advanced to be multistellar will no doubt have cracked either fusion or the stain sphere problem.
    - bhaak 6y ago
      A sufficiently advanced civilisation would be able to control their birth rate to whatever rate they would need at the moment. Think of an artificial womb (if that civilisation is mostly biological, if it's mostly robotic, controlling the birth rate becomes even easier). It's also likely that a self sufficient, long-term thinking planetary civilisation would limit their population to a certain size, to not needlessly exploit the resources that they have available.
      - 6y ago
  - tzs 6y ago
    > The problem with long lasting alien civilisations is that if they do exist, why aren't they here already? Colonizing the galaxy only takes a few millions years even with 0.1c. Suppose it turns out that there is nothing faster for interstellar travel than rockets or light sails. No wormholes stabilized with exotic matter. No warp drives. No other tricks. I'm not sure in that case that those long lasting civilizations would bother trying interstellar colonization. The round trip transport time between the home world and colonies would be so long that it is hard to come up with any economic benefit establishing such colonies provides to the home worlds.
    - est31 6y ago
      > it is hard to come up with any economic benefit establishing such colonies provides to the home worlds. If medium human life were only 4 weeks, nobody would find funding for a 1 year colonization trip across a different continent. You wouldn't find a crew when it'd take one generation just to cross the atlantic once. I think it's similar here. With future (bio-)technological improvements, we might live for hundreds or thousands of years. Suddenly individuals would start thinking really long term... At one point every niche of the solar system will either be declared a national park/treasure, or mined, filled with real estate developments, etc. We'd run out of space and some rich folks would meet on one of the private moons of Jupiter (like how there are private islands today) to discuss a venture towards another star.
    - zamfi 6y ago
      > The round trip transport time between the home world and colonies would be so long that it is hard to come up with any economic benefit establishing such colonies provides to the home worlds. Let’s just hope, for the sake of any beings already on other planets, that you are right. History here on Earth suggests that long journeys are not a sufficient obstacle for exploitation.
    - TheOtherHobbes 6y ago
      The problem with these discussions is everyone seems to assume colonising a galaxy is just like colonising a planet - so you have an Age of Exploration, and then you set up colonies, and stuff happens, and you have an Empire or a Federation, or something. This is really, really unlikely to be true, for all kinds of reasons. There's a huge difference between colonising a galaxy - which assumes some kind of uniform culture, and common strategic goals - and simply throwing more or less living/sentient stuff around a galaxy and hoping some of it sticks. We've gone from barely being noticeable on Earth to being in danger of being responsible for a planetary extinction event in around 12,000 years. We know nothing about building a stable culture that can last for millions of years. It's unlikely any sentient species will be able to learn that skill without making a lot of mistakes - some of which will be terminal. So galactic colonisation requires a lot more than solving the mechanics of transportation. And the "few million years at 0.1c" estimate is going to be Not Even Wrong.
  - dividedbyzero 6y ago
    There might be not a lot sense in doing that. Maybe infinite growth isn't desirable. Maybe becoming a hundred trillion people across a galaxy isn't so great.
cmenge 6y ago
Meh. According to https://en.m.wikipedia.org/wiki/Intergalactic_travel https://en.m.wikipedia.org/wiki/Intergalactic_travel, it takes a mere 28y to get to Andromeda if you have the tech to do constant 1g acceleration. You could say that is not "communication" from a civilization point of view, but if they can send us a live messenger it would sure be interesting?!
- vmception 6y ago
  Which part of Andromeda, it has a 110,000 light year radius
  - postalrat 6y ago
    Might only be a few hours difference for each end.
    - landryraccoon 6y ago
      Sure, if you just want to fly by. If you want to stick around, you'll have to decelerate.
      - blackrock 6y ago
        Isn’t that galaxy also rotating? So if you wanted to hit the far right corner of that galaxy, then don’t you have to calculate where it actually is now, since it took so many light years from that part of the galaxy to reach us. Then, you’d have to calculate where that part of the galaxy will be, by the time you reach it. Then, you aim yourself at those coordinates, and hope you don’t have any mechanical issues that will prevent you from gravitationally locking on to your destination star system.
- goatlover 6y ago
  The energy requirements to accelerate go up as you reach relativistic speeds, and you need to be able to decelerate as you reach the target.
karl11 6y ago
Hasn’t anyone read The Dark Forest?
- X6S1x6Okd1st 6y ago
  What probability do you think that a civilization will decide they are in a dark forest? So far our only example doesn't seem to act like we are.
  - s1artibartfast 6y ago
    There might be some crossover between civilizations that take dark forest precautions and the type of civilization that doesn’t kill itself on accident.
    - magicsmoke 6y ago
      Or it could be possible that a civilization pessimistic and risk-adverse enough make dark forest precautions a significant part of their culture wouldn't have the risk-taking needed to advance their technology to interstellar levels. Technological advancement and the possibility of self-destruction might go hand in hand.
- ladberg 6y ago
  Such a great trilogy! I hope we'll send out noticeable signals into space at some point down the line, and I wonder if our descendants in a few tens of thousands of years will look back on it as self-destructive hubris in the same way we look as burning coal now.
jacobush 6y ago
Explode a number of nukes in space, which forms a prime number pattern. For instance by cadence. That should get the attention of any listeners out there. There should be no natural process which could explain that. Bonus: An incredibly strong, directional and short pulse could be directed by placing a mylar parabolic shape behind the bombs. Just before being vaporised, the mylar would reflect the initial energy. The same could be done with the radio energy by a thin copper mesh. Edit - downvoter thinks it’s untenable or just a bad idea in case it works? :-)
- __s 6y ago
  Random math doesn't imply intelligence: https://en.wikipedia.org/wiki/Rule_30 https://en.wikipedia.org/wiki/Rule_30 is that shell intelligent? Wolfram has an alright interview where he considers this: https://www.youtube.com/watch?v=ez773teNFYA https://www.youtube.com/watch?v=ez773teNFYA My own thoughts: intelligence is something which you need to observe predicting the future, ie something proactively reacting to the future in order to achieve a goal. This means ideally you have a bit of interaction so that you can see that you're interacting with is capable of learning in response to you
  - jacobush 6y ago
    Primes are not random math, and primes do not occur in astronomy sightings. https://modulouniverse.com/2015/02/16/prime-numbers-and-et/ https://modulouniverse.com/2015/02/16/prime-numbers-and-et/
    - ben_w 6y ago
      In an alternate reality where we observed prime numbers in space, I suspect we’d be telling ourselves they must have a natural cause in the same way we’re looking at dark matter and arguing what type of particle it is made of. And if we did decide it had to be aliens, the point is they don’t have to be intelligent to do prime numbers — they might be space cicadas who evolved to spread around Oort clouds by gathering enough uranium to go prompt-critical[0]. From the point of view of aliens looking at us if we detonated nukes in a prime sequence, the same arguments apply. [0] this is a reference to a novel or short story which I can’t remember enough details of to find on Google or DDG.
dvduval 6y ago
Some civilizations may be able to populate multiple planets in their solar system and increase the chances that they will survive for perhaps thousands of years at a technologically higher level. During this time they may even be able to reach other solar systems. If they do that and can repeat it then they may be able to keep going millions of years. This may already be happening somewhere.
- duxup 6y ago
  What are the odds of having enough overlap of suitable planets each suitable enough with overlapping periods?
  - xcasperx 6y ago
    Depending on the technological level of these societies, they may be able to terraform plants rather quickly
  - newsbinator 6y ago
    They may not need planets. They could build habitats in space.
  - adrianN 6y ago
    If you look at our solar system, humans can survive on Earth, Mars, Venus and likely some larger moons without too much fictional technology. The universe seems to be full of rocky planets. The only insurmountable problem to living on a rocky planet with hydrogen, oxygen and carbon in some form really is gravity, if the planet is too big. But species that can travel interstellar distances must have the technology to live in space and only send robots to nearby planets or asteroids to mine raw materials. That increases the range of suitable systems considerably.
    - ncmncm 6y ago
      "Humans can survive on Mars"? Check your priors.
deleted 6y ago
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hliyan 6y ago
Forget travel. Even radio communications seem unlikely. I recently got depressed trying to calculate how much energy would be required to establish a radio link with a colony on a planet orbiting the nearest star (about 5 light years). Even if we use the entire output of a nuclear reactor to power the transmitter, even if we tighten the beam ten times beyond what's currently possible and even if the receiving collector is square kilometers wide, the signal is still going to be very weak. I can't even fathom how to make this work at 10K light year scale.
- akiselev 6y ago
  The receiver would be much, much bigger than a square kilometer by many (>6) orders of magnitude. Any civilization capable of interstellar travel would be very capable of setting up a planetary or solar system sized astronomical interferometer (aka hypertelescope [1]) using a large fleet of synchronized satellites. These satellites can be prototyped with today's technology and any interstellar civilization would be capable of both receivers and transmitters with far more power than we have attempted today. [1] https://en.wikipedia.org/wiki/Astronomical_interferometer https://en.wikipedia.org/wiki/Astronomical_interferometer
  - hliyan 6y ago
    Yes, but isn't interferometry only useful in increasing the angular resolution? It doesn't necessarily boost the signal.
    - akiselev 6y ago
      That's if you're trying to reconstruct a "picture" of what the interferometer is pointed at. If you control both the transmitter and receiver, you can use many different techniques to pack more information into the same amount of power. 2G cellular radios, for example, were 2 watts max power while 3G and 4G radios are 500 milliwatts max power despite being orders of magnitude faster thanks to better encoding due to radio sensitivity and spatial resolution due to MIMO - the cellular equivalent of an astronomical interferometer. The technical term is space-time block coding [1]. The speed negotiation would take at least 3x the distance between the two start systems though, until which time they'd be limited to a conservative estimate based on the channel impairment between the star systems, aka max expected noise between the two astronomical phased arrays. [1] https://en.wikipedia.org/wiki/Space%E2%80%93time_block_code https://en.wikipedia.org/wiki/Space%E2%80%93time_block_code
person_of_color 6y ago
Are there any scientific paradigm shifts to make FTL possible?
- javajosh 6y ago
  Paradigm shifts don't make physical phenomena possible. At best, they take an observed natural phenomena, isolate and amplify it. AFAIK nothing has been observed moving faster than light and I don't believe there is anything even predicted to. Of course, the details of black hole physics, and early cosmological physics, are very strange and full of contradictions. To relate back to the original topic, to last for a very long time, I would imagine a civilization would require some sort of central urge even beyond simple survival, and argue that studying black holes would be one of the best, and perhaps universal motivators. (The goal of survival in-and-of-itself at the civilizational level is ironically quite nihilistic!)
- MertsA 6y ago
  Best chance of anything hypothetically being possible in the very very far future would be not going faster than light, but contracting and expanding space. There's plenty of problems with that theory, one of many would be that it would hypothetically have an event horizon at the front while "moving" faster than light, which would be a big problem because the Hawking radiation from it would kill stuff. It's called an Alcubierre drive and it's a fun thought experiment at the very least. Due to the energy constraints if it was ever hypothetically possible it would need to envelop the vessel in a bubble that's downright infinitesimally small. You could pass right through a planet and not hit anything. https://en.wikipedia.org/wiki/Alcubierre_drive https://en.wikipedia.org/wiki/Alcubierre_drive But the only scientific method to exceed the speed of light is to loosen the fiber optic cables on your neutrino detector. https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly https://en.wikipedia.org/wiki/Faster-than-light_neutrino_ano...
- 7thaccount 6y ago
  I think you'd know if there were. As far as I know (not a physicist), it takes infinite energy to reach FTL, so out of the question with modern science as you've said. As a non scientist, I'm also confused with some of the relativistic implications of FTL. I think motion through space and motion through time add up to the speed of light. If so, time would freeze when hitting the speed of light, but does that happen to the traveler moving at C, or to the outside observer? Also, if traveling faster than light (FTL), do I go back in time? Again, is that from the traveler or outsiders perspective? As far as getting FTL, you've probably heard of the Alcuberrie (spelling) drive which expands spacetime behind a ship and contracts in front of it to push a ship through spacetime via a bubble? Sounds great, but I think it requires exotic materials which don't exist. So we're stuck. I'm pointing this out in the chance you don't already know this. My hope is that within the next century or millennia, our understanding of math and physics will advance to a point to where things like wormholes become possible, but it'll be long after I'm dead. What worries me is if we're nearing the end of what the human brain is capable of realistically uncovering. Like if my brain's network was significantly denser and able to think better, maybe we could come up with something? I don't think the solutions to the next problems will be a single equation like some physicists like to claim (note they're far more qualified than I to speculate on this). I just see things like the proof for Fermat's Last Theorem that is like 80 pages and one man took like a decade to figure out and other mathematicians took like a year to check. Someone like me has zero chance of intellectually following that. If we have indeed "picked all the low hanging fruit" we can expect very small marginal gains in the upcoming years even with legions of scientists. My hope is that we're just in another phase waiting for another Newton or Einstein to come up with a single beautiful idea that revolutionizes the field and leads to an explosion of progress.
pjdorrell 6y ago
The authors of the paper do various calculations to arrive at 36. How do they determine f_l, the probability of life originating on a suitable planet? They follow the "Principle of Mediocrity", ie life exists on Earth, and we are not special, so probably it exists anywhere it can exist and f_l = 1. This is the exact opposite of the Anthropic Principle, which says (correctly) that we cannot deduce anything about the probability of life originating from the fact of our own existence. If f_l isn't 1, and it's some smaller number, like 1^-1000, then there won't be 36 alien civilisations in the galaxy - there will only be zero. Even in the observable universe, there will be zero alien civilisations.
- throwaway888abc 6y ago
  Reality is frequently inaccurate.
  - ncmncm 6y ago
    Atypical, anyway.
- kranner 6y ago
  > This is the exact opposite of the Anthropic Principle, which says (correctly) that we cannot deduce anything about the probability of life originating from the fact of our own existence. Your definition of the Anthropic Principle seems to clash with the Wikipedia definition [1], which states: > The anthropic principle is the philosophical premise that any data we collect about the universe is filtered by the fact that, in order for it to be observable at all, the universe must have been compatible with the emergence of conscious and sapient life that observes it. [1] https://en.wikipedia.org/wiki/Anthropic_principle https://en.wikipedia.org/wiki/Anthropic_principle Also you use the word "correctly" for your definition, but as it isn't self-evident, some sort of proof should probably be required.
  - cthalupa 6y ago
    Well, even within the wikipedia article you see quite a few definitions under 'variants'. It's also nearly a word for word copy of how it is defined in contrast to the mediocrity principle ( https://en.wikipedia.org/wiki/Mediocrity_principle https://en.wikipedia.org/wiki/Mediocrity_principle ) Either way, his point is fundamentally pretty close to even the WAP definition in the summary. I think it's fairly self evident, though. If there is only one set of observers in the entirety of the observable universe, those observers would be inaccurate in assuming that they are unlikely to be special because they exist and therefor others likely to as well. We just can't make a deduction about the probability of life based on the fact we exist, because for us to make that observation we have to exist, regardless of (im)probable it was. You can reach the same conclusion just thinking about selection bias - we have selected for intelligent life out of necessity, because if we hadn't, we couldn't be around to make the argument either way.
networkimprov 6y ago
For great interviews with leading scientists on this and other astronomy topics, see Event Horizon podcast https://www.youtube.com/channel/UCz3qvETKooktNgCvvheuQDw/videos https://www.youtube.com/channel/UCz3qvETKooktNgCvvheuQDw/vid... (I'm just a happy listener.)
nine_k 6y ago
Cetaceans are considered sentient, the way humans are sentient, by a wide scientific consensus, e.g. [1]. Some degree of sentience is also assumed by the scientific community to be present in a lot of other animals [2]. Still the successes in contacting these nonhuman sentient beings, even if they gladly support such contacts, like dolphins, is very limited at best. And those are our close relatives, fellow mammals, sharing the planet with us. Now imagine an attempt to contact a sentient being which developed and lives in an environment totally alien to humans. [1]: https://www.bbc.com/news/world-17116882 https://www.bbc.com/news/world-17116882 [2]: http://www.animalcognition.org/2015/03/25/the-declaration-of-nonhuman-animal-conciousness/ http://www.animalcognition.org/2015/03/25/the-declaration-of...
- newsbinator 6y ago
  Communication is easier if they developed math too.
  - close04 6y ago
    In order for someone on another planet to be detectable by us humans with our present tech they would have to broadcast radio signals. We developed this tech a little over a century ago. And as a civilization we had plenty of opportunities to self destruct, from nuclear and biological warfare, to destroying the environment. We also have the chance of developing a "better than radio" communication method that's completely obscure to us at this point. The window of of that civilization being detectable is squarely between them developing radio and them dying off or using some tech that we cannot discern as artificial signals. The window for us detecting them has been ~50 years so far. Given the size of the galaxy and the minuteness of that window overlap it's pretty clear the chances of communication are slim. And indeed even if we do detect something, calling it communication might really be pushing our definition of that.
- adrianN 6y ago
  We are pretty good at communicating with our pets.
  - 6y ago
pp19dd 6y ago
At this point of theoretical speculation, it's perhaps just as creatively interesting to visit sci-fi on first contact situations and evaluate their approaches to see how they mesh with our astronomical observations. The book that came to mind is a classic, "The Mote in God's Eye." Though there are dozens of delightful variations and imaginative situations, such as with "The Saturn Run." There's an entire spectrum that's been imagined and explored.
rkagerer 6y ago
Then they assumed that these civilizations retained [communication] capacity for about 100 years — again about as long as we've had it. Does that part of their calculation seem awfully conservative?
- yummypaint 6y ago
  I wouldn't find it surprising if self destruction were a common occurence after intelligent life changes its environment enough to develop long range communication. Unless the technology develops at a comparable rate to evolution, there will always be a sharp discontinuity associated with industrialization that suddenly grants the ability to manipulate things on a planetary scale. The lifeforms will be placed in a completely novel situation without evolved mental hardware needed to see the danger. Just like how posting to facebook while driving doesn't feel dangerous in the way standing near the edge of a cliff does. I often wonder if this is where the great filter is located.
- stkdump 6y ago
  Given that we only have ourself to compare with and we can't look into the future, I think that is looking at it based on facts. Sure, we can identify this as one of the big unknowns in the calculation, but 100 years is what we know.
- robbrown451 6y ago
  That jumped out at me as well. It seems to me highly unlikely that humans will wipe themselves out in the next hundred years, and if they don't, even less likely beyond that. Maybe, but I doubt it.
- pharke 6y ago
  So their calculation is actually for the number of civilizations in the galaxy that are at exactly the same level of technological development that we are. Even assuming that some percentage of civilizations annihilate themselves beyond recovery there must still be a very long tail of ones that only do so at a later date as well as those that do not and those that recover at some later time.
millstone 6y ago
The plan seems to be "to find intelligent civilizations, look for Earth-like planets that can harbor life." How terribly narrow minded. > you'd think the chance that there is intelligent extraterrestrial life in our galaxy seems enormous "And the Earthling rocket ships departed Planet X3, having found no life, only an advanced civilization of extraterrestrial robots." > Another study out of the University of British Columbia looked at the number of sun-like stars in the galaxy and estimated that one in five of them could have an Earth-like planet On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents. Life is surely bigger than Earth-like planets. And Intelligence is surely bigger than Life. In Sagan's book Contact, the hard problem was not finding intelligence, but recognizing it. By the end, we learn that the arrangement of the stars and the digits of pi itself carry a message. This is the level of thinking that our search calls for.
- bryanrasmussen 6y ago
  > And Intelligence is surely bigger than Life. I don't think your advanced civilization of extraterrestrial robots is doing enough work to establish this particular point. That said I would think looking for earth like planets is not so much just for finding life, but also for the point of making it easier to recognize it as life, and finally hopefully having enough points in common to communicate.
- TomMarius 6y ago
  There are certain realities that limit where life can be established and flourish, and while different kinds of life might be possible, they're extremely unlikely due to basic physical/chemical constraints, amount of other elements in the universe compared to hydrogen and carbon and oxygen, etc. And even the most inhospitable place on Earth is pretty okay by galactic standards - Earth's magnetic field, characteristics of our star and our planetary configuration being the main reasons.
- tsimionescu 6y ago
  > On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents. And yet, all life on Earth has the same basic structure. The most likely reason for this is that life only originated once, and in one "place". This observation significantly reduces the probability we should ascribe for life to appear, and/or the specificity of the conditions required. For example, we know for sure that a planet like the Earth today is completely inhospitable to the emergence of life (there has not been an abiogenesis event for billions of years). The other option is that life has emerged in many places/times on Earth, but with the exact same structure. While unlikely, this would suggest that life must have a very specific structure, that at least on Earth-like planets we should also expect RNA and DNA based life at least. This would also suggest that the likelihood of other kinds of life existing is smaller than initially could have been conceived. And even with this assumption, it would still not be clear that life is appearing on Earth today anymore, as the life forms we've looked at seem to have a phylogenetic link with other life (though our methods may be weak if the possibility of abiogenesis were correct). And even if abiogenesis was still occurring on Earth, it would have to be in some remote place in extreme conditions, as we have tried in all regular places with no success. Overall, my belief is that the emergence of life is likely a vastly improbable event, and that we shouldn't expect to "see" a living (or formerly living) being that is not related to life on Earth in the lifetime of the Earth. > And Intelligence is surely bigger than Life. This seems a mystical belief, given all we know of the world.
LatteLazy 6y ago
Isn't the who point of the drake equation to discuss the factors? And most of the factors can't actually be measured until you've met a few dozen other civilisations and compared histories?
jasonlfunk 6y ago
> Of course since no one knows how long intelligent civilizations last, (given our current trajectory, some might guess not very long) These people must have a very short sighted view of history? Our current trajectory for almost everything that matters is positive. Longer life spans, fewer wars, better medicine and technology, average base-level knowledge, etc. Barring some global unavoidable catastrophe, there is no reason to think we are going anywhere very soon.
- tsimionescu 6y ago
  > Barring some global unavoidable catastrophe, there is no reason to think we are going anywhere very soon. If only we didn't live during a huge ecological disaster that is threatening to destroy the livelihoods of hundreds of millions of people directly, with unforeseeable consequences for the rest of the world; which the major powers of the world are unwilling to act in any significant way to curtail; and which seems to require a re-structuring of the entire world's economy to actually solve... Looking at the world right now, we know one thing for sure: none of the trends we see today will be relevant in 100 years. One way or another, the world will go through massive changes whose scope can't be predicted. One possibility is global warming will continue unabated until we have hundreds of millions of people migrating from rapidly submerging areas (Bangladesh being one of the largest concentrations of population in the world living a few meters above sea levels), most likely followed by some kind of global war to prevent or redirect the massive migrations. Another is that the global economy will be completely re-created to stop the production of greenhouse gases dead in its tracks, almost certainly in a non-capitalist system, since capitalism simply can't deal with externalities. The required political and economic shifts are hard to imagine, and the resulting world is equally hard to predict. And of course, we are still always a few madmen away from nuclear war, with many of the world's most tense regions having nuclear weapons aimed at their enemies. Could global warming start a resource war between India and Pakistan that would lead to them using their arsenals? Could Israel decide to use its illegal nuclear weapons to attack Iran in a "defensive first strike"? Could the US decide that its interests are important enough that, as its soft power wanes, it could launch a bomb at some country to remind everyone of its hard power? Could the Europeans spark a new war, either among themselves or against some common threat, and feel the need to use their nuclear arsenal? Could the Chinese? As long as nuclear weapons exist, they are an ever growing threat. Remember that just in the last few years, the long standing US-Russian non-proliferation treaty was unilaterally ended by the US, signalling a vast increase in the risk of nuclear weapons actually seeing use again.
simonkafan 6y ago
I read the paper and I find it highly unserious how frivolously they assigned some probability to the question how many intelligent civilizations there are in the universe. Their key assumption is: "We assume that if an SP remains in the circumstellar Habitable Zone (HZ) for a time equal to the current age of the Earth it will develop intelligent, communicative life." (page 5 at https://arxiv.org/ftp/arxiv/papers/2004/2004.03968.pdf https://arxiv.org/ftp/arxiv/papers/2004/2004.03968.pdf) Why? Why do you assume a planet will develop intelligent life when it remains in the Habitable Zone long enough? Just because it happend on Earth? And they continue with: "[...] according to the Copernican Principle – we propose that the likelihood of the development of life, and even intelligent life, should be broadly uniformly distributed amongst any suitable habitats" We have no clue how likely it was at Earth that life developed at all. Maybe it was just a chain of many lucky coincidences that happen once in 10 billion years. How is distribution any relevant then?
- bhaak 6y ago
  With other assumptions, they would arrive at 0 intelligent civilisations in the galaxy. That would make the rest of the paper void. :-) Nobody knows how life is distributed in the galaxy. Assuming that we are not special (the Copernican Principle) is a valid prerequisite. As it neither can be proved or disproved, it's not unserious to just state what the unproven assumptions are.
- dahfizz 6y ago
  One thing that bothers me is that papers like this always assume alien life will look exactly like life on Earth. It must be the same distance from the sun as us, have water and proteins like us, etc. If we effectively limit the definition of "life" to "the types of organisms we see on Earth", then of course we will never find life anywhere else. Maybe there are aliens that live on a gas giant and they "eat" the lighting rather than food, and their bodies look more like circuitry than the chemical life on Earth. Maybe there is a planet with a very strong magnetic field, and the life there is kind of like an electromagnet. They have bodies high in copper and the current of the ocean moves them through the magnetic field and generates electrical energy. It makes sense that we restrict our search for life forms we know to be possible while we are stuck with limited tools at our disposal. But I don't want us to overlook some amazing discoveries because we have put blinders on.
loudouncodes 6y ago
How can this article, as well as the hundreds of comments here, not acknowledge that all they are doing is solving the Drake Equation for new values they are estimating?
smartmic 6y ago
Civilizations fail. Here is more on that and the related Fermi paradox : http://t3x.org/bits/doomed/index.html http://t3x.org/bits/doomed/index.html
mchusma 6y ago
Issac Arthur's podcast is the best resource on these matters. Amazing work, and makes this paper seem very week. He identifies many possible filters beyond the Drake equation. If you like this sort of discussion, you will almost certainly like the podcast. Relevant playlist https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh8TTOnCgRkLdU https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh...
planetis 6y ago
Im disappointed they did't arrive at 42, but 36
historyremade 6y ago
This is intellicist. Aliens should protest!!
robodale 6y ago
I worry that other far more advanced civilizations out there routinely stamp out any new "pest" civilizations....much like how I handle ant colonies behind my house. They get too large or too close...then I knock them out.

78 points by imheretolearn 6y ago

Why do they assume that an alien civilisation could only hold communication technology for a hundred years? Surely there’s nothing really holding them back from it unless they wiped themselves out, and is there any reason to believe that at least some of them couldn’t last for thousands or even millions of years?

austincheney 6y ago
> "The search for intelligent life is only expected to yield a positive observation if the average life-span of [communicating extra-terrestrial intelligence] within our Galaxy is 3,060 years. That is to say, our communicating civilization here on Earth will need to persist for 6,120 years beyond the advent of long-range radio technology (approximately 100 years ago) before we can expect a [search for extra-terrestrial intelligence] two-way communication." https://edition.cnn.com/2020/06/15/world/intelligent-civilizations-galaxy-scn-trnd/index.html https://edition.cnn.com/2020/06/15/world/intelligent-civiliz...
bhaak 6y ago
The problem with long lasting alien civilisations is that if they do exist, why aren't they here already? Colonizing the galaxy only takes a few millions years even with 0.1c. So far, we only have proof that civilisations can exist for at least several thousand years if you consider the Human civilisation. But so far, the data on civilisations capable of interstellar communication doesn't look too promising. The "unless they wiped themselves out" is the big question. Are we behind or in front of the Great Filter.
- GuiA 6y ago
  By definition there has to be a first intergalactic civilization, if there is to be at least one. The universe is ~15B years old, and we expect it to keep forming stars (as good as any of a metric for “hospitable to life”) for another trillion years. In other words, we’re in the first percent or so of the lifespan of the universe. Doesn’t seem too crazy that if we start conquering the stars, we might be the first ever species to do so. (And if history is any indication, we’ll probably cause some sort of galactic global warming in the process, that all starfaring species after us will curse us for)
  - akiselev 6y ago
    > (And if history is any indication, we’ll probably cause some sort of galactic global warming in the process, that all starfaring species after us will curse us for) The only serious theoretical FTL paper (Alcubierre drive) I know of requires exotic matter (negative mass) or energy equivalents of entire planets so if we ever manage to build it, I think that's a fair bet. Another paper calculated that the space-time bubble created by the Alcubierre drive would capture radiation and particles along its path, creating a gamma ray burst at the destination in a large cone in the direction of travel. Meaning, we'd be sending deadly bursts of radiation all over the galaxy that would wipe out all carbon based life for tens or hundreds of light years every single jump. A rogue actor or a miscalculation could wipe out significant fractions of our own civilization.
- bitcurious 6y ago
  > The problem with long lasting alien civilisations is that if they do exist, why aren't they here already? Colonizing the galaxy only takes a few millions years even with 0.1c The kind of colonization you’re describing requires exponential growth, but at least on Earth we’ve seen that birth rates dropping in developed nations.
  - pedrosorio 6y ago
    There is no evidence this will hold true in a colonization scenario.
  - adventured 6y ago
    Exponential growth doesn't inherently require population expansion. This would especially be true for a far more advanced civilization. You could dramatically amplify your colonization efforts with machines, reducing your need for traditional population expansion (productivity expansion in tandem with population contraction is exactly what we're going to see on Earth this century).
    - bitcurious 6y ago
      Without population growth you lose the motivation. Communication gets harder every time you add a star to your civilization, unless you somehow break the speed of light. Resource use is unlikely to be a motivator - a civilization sufficiently advanced to be multistellar will no doubt have cracked either fusion or the stain sphere problem.
  - bhaak 6y ago
    A sufficiently advanced civilisation would be able to control their birth rate to whatever rate they would need at the moment. Think of an artificial womb (if that civilisation is mostly biological, if it's mostly robotic, controlling the birth rate becomes even easier). It's also likely that a self sufficient, long-term thinking planetary civilisation would limit their population to a certain size, to not needlessly exploit the resources that they have available.
    - 6y ago
- tzs 6y ago
  > The problem with long lasting alien civilisations is that if they do exist, why aren't they here already? Colonizing the galaxy only takes a few millions years even with 0.1c. Suppose it turns out that there is nothing faster for interstellar travel than rockets or light sails. No wormholes stabilized with exotic matter. No warp drives. No other tricks. I'm not sure in that case that those long lasting civilizations would bother trying interstellar colonization. The round trip transport time between the home world and colonies would be so long that it is hard to come up with any economic benefit establishing such colonies provides to the home worlds.
  - est31 6y ago
    > it is hard to come up with any economic benefit establishing such colonies provides to the home worlds. If medium human life were only 4 weeks, nobody would find funding for a 1 year colonization trip across a different continent. You wouldn't find a crew when it'd take one generation just to cross the atlantic once. I think it's similar here. With future (bio-)technological improvements, we might live for hundreds or thousands of years. Suddenly individuals would start thinking really long term... At one point every niche of the solar system will either be declared a national park/treasure, or mined, filled with real estate developments, etc. We'd run out of space and some rich folks would meet on one of the private moons of Jupiter (like how there are private islands today) to discuss a venture towards another star.
  - zamfi 6y ago
    > The round trip transport time between the home world and colonies would be so long that it is hard to come up with any economic benefit establishing such colonies provides to the home worlds. Let’s just hope, for the sake of any beings already on other planets, that you are right. History here on Earth suggests that long journeys are not a sufficient obstacle for exploitation.
  - TheOtherHobbes 6y ago
    The problem with these discussions is everyone seems to assume colonising a galaxy is just like colonising a planet - so you have an Age of Exploration, and then you set up colonies, and stuff happens, and you have an Empire or a Federation, or something. This is really, really unlikely to be true, for all kinds of reasons. There's a huge difference between colonising a galaxy - which assumes some kind of uniform culture, and common strategic goals - and simply throwing more or less living/sentient stuff around a galaxy and hoping some of it sticks. We've gone from barely being noticeable on Earth to being in danger of being responsible for a planetary extinction event in around 12,000 years. We know nothing about building a stable culture that can last for millions of years. It's unlikely any sentient species will be able to learn that skill without making a lot of mistakes - some of which will be terminal. So galactic colonisation requires a lot more than solving the mechanics of transportation. And the "few million years at 0.1c" estimate is going to be Not Even Wrong.
- dividedbyzero 6y ago
  There might be not a lot sense in doing that. Maybe infinite growth isn't desirable. Maybe becoming a hundred trillion people across a galaxy isn't so great.

cmenge 6y ago

Meh. According to https://en.m.wikipedia.org/wiki/Intergalactic_travel https://en.m.wikipedia.org/wiki/Intergalactic_travel, it takes a mere 28y to get to Andromeda if you have the tech to do constant 1g acceleration. You could say that is not "communication" from a civilization point of view, but if they can send us a live messenger it would sure be interesting?!

vmception 6y ago
Which part of Andromeda, it has a 110,000 light year radius
- postalrat 6y ago
  Might only be a few hours difference for each end.
  - landryraccoon 6y ago
    Sure, if you just want to fly by. If you want to stick around, you'll have to decelerate.
    - blackrock 6y ago
      Isn’t that galaxy also rotating? So if you wanted to hit the far right corner of that galaxy, then don’t you have to calculate where it actually is now, since it took so many light years from that part of the galaxy to reach us. Then, you’d have to calculate where that part of the galaxy will be, by the time you reach it. Then, you aim yourself at those coordinates, and hope you don’t have any mechanical issues that will prevent you from gravitationally locking on to your destination star system.
goatlover 6y ago
The energy requirements to accelerate go up as you reach relativistic speeds, and you need to be able to decelerate as you reach the target.

karl11 6y ago

Hasn’t anyone read The Dark Forest?

X6S1x6Okd1st 6y ago
What probability do you think that a civilization will decide they are in a dark forest? So far our only example doesn't seem to act like we are.
- s1artibartfast 6y ago
  There might be some crossover between civilizations that take dark forest precautions and the type of civilization that doesn’t kill itself on accident.
  - magicsmoke 6y ago
    Or it could be possible that a civilization pessimistic and risk-adverse enough make dark forest precautions a significant part of their culture wouldn't have the risk-taking needed to advance their technology to interstellar levels. Technological advancement and the possibility of self-destruction might go hand in hand.
ladberg 6y ago
Such a great trilogy! I hope we'll send out noticeable signals into space at some point down the line, and I wonder if our descendants in a few tens of thousands of years will look back on it as self-destructive hubris in the same way we look as burning coal now.

jacobush 6y ago

Explode a number of nukes in space, which forms a prime number pattern. For instance by cadence. That should get the attention of any listeners out there. There should be no natural process which could explain that. Bonus: An incredibly strong, directional and short pulse could be directed by placing a mylar parabolic shape behind the bombs. Just before being vaporised, the mylar would reflect the initial energy. The same could be done with the radio energy by a thin copper mesh. Edit - downvoter thinks it’s untenable or just a bad idea in case it works? :-)

__s 6y ago
Random math doesn't imply intelligence: https://en.wikipedia.org/wiki/Rule_30 https://en.wikipedia.org/wiki/Rule_30 is that shell intelligent? Wolfram has an alright interview where he considers this: https://www.youtube.com/watch?v=ez773teNFYA https://www.youtube.com/watch?v=ez773teNFYA My own thoughts: intelligence is something which you need to observe predicting the future, ie something proactively reacting to the future in order to achieve a goal. This means ideally you have a bit of interaction so that you can see that you're interacting with is capable of learning in response to you
- jacobush 6y ago
  Primes are not random math, and primes do not occur in astronomy sightings. https://modulouniverse.com/2015/02/16/prime-numbers-and-et/ https://modulouniverse.com/2015/02/16/prime-numbers-and-et/
  - ben_w 6y ago
    In an alternate reality where we observed prime numbers in space, I suspect we’d be telling ourselves they must have a natural cause in the same way we’re looking at dark matter and arguing what type of particle it is made of. And if we did decide it had to be aliens, the point is they don’t have to be intelligent to do prime numbers — they might be space cicadas who evolved to spread around Oort clouds by gathering enough uranium to go prompt-critical[0]. From the point of view of aliens looking at us if we detonated nukes in a prime sequence, the same arguments apply. [0] this is a reference to a novel or short story which I can’t remember enough details of to find on Google or DDG.

dvduval 6y ago

Some civilizations may be able to populate multiple planets in their solar system and increase the chances that they will survive for perhaps thousands of years at a technologically higher level. During this time they may even be able to reach other solar systems. If they do that and can repeat it then they may be able to keep going millions of years. This may already be happening somewhere.

duxup 6y ago
What are the odds of having enough overlap of suitable planets each suitable enough with overlapping periods?
- xcasperx 6y ago
  Depending on the technological level of these societies, they may be able to terraform plants rather quickly
- newsbinator 6y ago
  They may not need planets. They could build habitats in space.
- adrianN 6y ago
  If you look at our solar system, humans can survive on Earth, Mars, Venus and likely some larger moons without too much fictional technology. The universe seems to be full of rocky planets. The only insurmountable problem to living on a rocky planet with hydrogen, oxygen and carbon in some form really is gravity, if the planet is too big. But species that can travel interstellar distances must have the technology to live in space and only send robots to nearby planets or asteroids to mine raw materials. That increases the range of suitable systems considerably.
  - ncmncm 6y ago
    "Humans can survive on Mars"? Check your priors.

deleted 6y ago

[deleted]

hliyan 6y ago

Forget travel. Even radio communications seem unlikely. I recently got depressed trying to calculate how much energy would be required to establish a radio link with a colony on a planet orbiting the nearest star (about 5 light years). Even if we use the entire output of a nuclear reactor to power the transmitter, even if we tighten the beam ten times beyond what's currently possible and even if the receiving collector is square kilometers wide, the signal is still going to be very weak. I can't even fathom how to make this work at 10K light year scale.

akiselev 6y ago
The receiver would be much, much bigger than a square kilometer by many (>6) orders of magnitude. Any civilization capable of interstellar travel would be very capable of setting up a planetary or solar system sized astronomical interferometer (aka hypertelescope [1]) using a large fleet of synchronized satellites. These satellites can be prototyped with today's technology and any interstellar civilization would be capable of both receivers and transmitters with far more power than we have attempted today. [1] https://en.wikipedia.org/wiki/Astronomical_interferometer https://en.wikipedia.org/wiki/Astronomical_interferometer
- hliyan 6y ago
  Yes, but isn't interferometry only useful in increasing the angular resolution? It doesn't necessarily boost the signal.
  - akiselev 6y ago
    That's if you're trying to reconstruct a "picture" of what the interferometer is pointed at. If you control both the transmitter and receiver, you can use many different techniques to pack more information into the same amount of power. 2G cellular radios, for example, were 2 watts max power while 3G and 4G radios are 500 milliwatts max power despite being orders of magnitude faster thanks to better encoding due to radio sensitivity and spatial resolution due to MIMO - the cellular equivalent of an astronomical interferometer. The technical term is space-time block coding [1]. The speed negotiation would take at least 3x the distance between the two start systems though, until which time they'd be limited to a conservative estimate based on the channel impairment between the star systems, aka max expected noise between the two astronomical phased arrays. [1] https://en.wikipedia.org/wiki/Space%E2%80%93time_block_code https://en.wikipedia.org/wiki/Space%E2%80%93time_block_code

person_of_color 6y ago

Are there any scientific paradigm shifts to make FTL possible?

javajosh 6y ago
Paradigm shifts don't make physical phenomena possible. At best, they take an observed natural phenomena, isolate and amplify it. AFAIK nothing has been observed moving faster than light and I don't believe there is anything even predicted to. Of course, the details of black hole physics, and early cosmological physics, are very strange and full of contradictions. To relate back to the original topic, to last for a very long time, I would imagine a civilization would require some sort of central urge even beyond simple survival, and argue that studying black holes would be one of the best, and perhaps universal motivators. (The goal of survival in-and-of-itself at the civilizational level is ironically quite nihilistic!)
MertsA 6y ago
Best chance of anything hypothetically being possible in the very very far future would be not going faster than light, but contracting and expanding space. There's plenty of problems with that theory, one of many would be that it would hypothetically have an event horizon at the front while "moving" faster than light, which would be a big problem because the Hawking radiation from it would kill stuff. It's called an Alcubierre drive and it's a fun thought experiment at the very least. Due to the energy constraints if it was ever hypothetically possible it would need to envelop the vessel in a bubble that's downright infinitesimally small. You could pass right through a planet and not hit anything. https://en.wikipedia.org/wiki/Alcubierre_drive https://en.wikipedia.org/wiki/Alcubierre_drive But the only scientific method to exceed the speed of light is to loosen the fiber optic cables on your neutrino detector. https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly https://en.wikipedia.org/wiki/Faster-than-light_neutrino_ano...
7thaccount 6y ago
I think you'd know if there were. As far as I know (not a physicist), it takes infinite energy to reach FTL, so out of the question with modern science as you've said. As a non scientist, I'm also confused with some of the relativistic implications of FTL. I think motion through space and motion through time add up to the speed of light. If so, time would freeze when hitting the speed of light, but does that happen to the traveler moving at C, or to the outside observer? Also, if traveling faster than light (FTL), do I go back in time? Again, is that from the traveler or outsiders perspective? As far as getting FTL, you've probably heard of the Alcuberrie (spelling) drive which expands spacetime behind a ship and contracts in front of it to push a ship through spacetime via a bubble? Sounds great, but I think it requires exotic materials which don't exist. So we're stuck. I'm pointing this out in the chance you don't already know this. My hope is that within the next century or millennia, our understanding of math and physics will advance to a point to where things like wormholes become possible, but it'll be long after I'm dead. What worries me is if we're nearing the end of what the human brain is capable of realistically uncovering. Like if my brain's network was significantly denser and able to think better, maybe we could come up with something? I don't think the solutions to the next problems will be a single equation like some physicists like to claim (note they're far more qualified than I to speculate on this). I just see things like the proof for Fermat's Last Theorem that is like 80 pages and one man took like a decade to figure out and other mathematicians took like a year to check. Someone like me has zero chance of intellectually following that. If we have indeed "picked all the low hanging fruit" we can expect very small marginal gains in the upcoming years even with legions of scientists. My hope is that we're just in another phase waiting for another Newton or Einstein to come up with a single beautiful idea that revolutionizes the field and leads to an explosion of progress.

pjdorrell 6y ago

The authors of the paper do various calculations to arrive at 36. How do they determine f_l, the probability of life originating on a suitable planet? They follow the "Principle of Mediocrity", ie life exists on Earth, and we are not special, so probably it exists anywhere it can exist and f_l = 1. This is the exact opposite of the Anthropic Principle, which says (correctly) that we cannot deduce anything about the probability of life originating from the fact of our own existence. If f_l isn't 1, and it's some smaller number, like 1^-1000, then there won't be 36 alien civilisations in the galaxy - there will only be zero. Even in the observable universe, there will be zero alien civilisations.

throwaway888abc 6y ago
Reality is frequently inaccurate.
- ncmncm 6y ago
  Atypical, anyway.
kranner 6y ago
> This is the exact opposite of the Anthropic Principle, which says (correctly) that we cannot deduce anything about the probability of life originating from the fact of our own existence. Your definition of the Anthropic Principle seems to clash with the Wikipedia definition [1], which states: > The anthropic principle is the philosophical premise that any data we collect about the universe is filtered by the fact that, in order for it to be observable at all, the universe must have been compatible with the emergence of conscious and sapient life that observes it. [1] https://en.wikipedia.org/wiki/Anthropic_principle https://en.wikipedia.org/wiki/Anthropic_principle Also you use the word "correctly" for your definition, but as it isn't self-evident, some sort of proof should probably be required.
- cthalupa 6y ago
  Well, even within the wikipedia article you see quite a few definitions under 'variants'. It's also nearly a word for word copy of how it is defined in contrast to the mediocrity principle ( https://en.wikipedia.org/wiki/Mediocrity_principle https://en.wikipedia.org/wiki/Mediocrity_principle ) Either way, his point is fundamentally pretty close to even the WAP definition in the summary. I think it's fairly self evident, though. If there is only one set of observers in the entirety of the observable universe, those observers would be inaccurate in assuming that they are unlikely to be special because they exist and therefor others likely to as well. We just can't make a deduction about the probability of life based on the fact we exist, because for us to make that observation we have to exist, regardless of (im)probable it was. You can reach the same conclusion just thinking about selection bias - we have selected for intelligent life out of necessity, because if we hadn't, we couldn't be around to make the argument either way.

networkimprov 6y ago

For great interviews with leading scientists on this and other astronomy topics, see Event Horizon podcast https://www.youtube.com/channel/UCz3qvETKooktNgCvvheuQDw/videos https://www.youtube.com/channel/UCz3qvETKooktNgCvvheuQDw/vid... (I'm just a happy listener.)

nine_k 6y ago

Cetaceans are considered sentient, the way humans are sentient, by a wide scientific consensus, e.g. [1]. Some degree of sentience is also assumed by the scientific community to be present in a lot of other animals [2]. Still the successes in contacting these nonhuman sentient beings, even if they gladly support such contacts, like dolphins, is very limited at best. And those are our close relatives, fellow mammals, sharing the planet with us. Now imagine an attempt to contact a sentient being which developed and lives in an environment totally alien to humans. [1]: https://www.bbc.com/news/world-17116882 https://www.bbc.com/news/world-17116882 [2]: http://www.animalcognition.org/2015/03/25/the-declaration-of-nonhuman-animal-conciousness/ http://www.animalcognition.org/2015/03/25/the-declaration-of...

newsbinator 6y ago
Communication is easier if they developed math too.
- close04 6y ago
  In order for someone on another planet to be detectable by us humans with our present tech they would have to broadcast radio signals. We developed this tech a little over a century ago. And as a civilization we had plenty of opportunities to self destruct, from nuclear and biological warfare, to destroying the environment. We also have the chance of developing a "better than radio" communication method that's completely obscure to us at this point. The window of of that civilization being detectable is squarely between them developing radio and them dying off or using some tech that we cannot discern as artificial signals. The window for us detecting them has been ~50 years so far. Given the size of the galaxy and the minuteness of that window overlap it's pretty clear the chances of communication are slim. And indeed even if we do detect something, calling it communication might really be pushing our definition of that.
adrianN 6y ago
We are pretty good at communicating with our pets.
- 6y ago

pp19dd 6y ago

At this point of theoretical speculation, it's perhaps just as creatively interesting to visit sci-fi on first contact situations and evaluate their approaches to see how they mesh with our astronomical observations. The book that came to mind is a classic, "The Mote in God's Eye." Though there are dozens of delightful variations and imaginative situations, such as with "The Saturn Run." There's an entire spectrum that's been imagined and explored.

rkagerer 6y ago

Then they assumed that these civilizations retained [communication] capacity for about 100 years — again about as long as we've had it. Does that part of their calculation seem awfully conservative?

yummypaint 6y ago
I wouldn't find it surprising if self destruction were a common occurence after intelligent life changes its environment enough to develop long range communication. Unless the technology develops at a comparable rate to evolution, there will always be a sharp discontinuity associated with industrialization that suddenly grants the ability to manipulate things on a planetary scale. The lifeforms will be placed in a completely novel situation without evolved mental hardware needed to see the danger. Just like how posting to facebook while driving doesn't feel dangerous in the way standing near the edge of a cliff does. I often wonder if this is where the great filter is located.
stkdump 6y ago
Given that we only have ourself to compare with and we can't look into the future, I think that is looking at it based on facts. Sure, we can identify this as one of the big unknowns in the calculation, but 100 years is what we know.
robbrown451 6y ago
That jumped out at me as well. It seems to me highly unlikely that humans will wipe themselves out in the next hundred years, and if they don't, even less likely beyond that. Maybe, but I doubt it.
pharke 6y ago
So their calculation is actually for the number of civilizations in the galaxy that are at exactly the same level of technological development that we are. Even assuming that some percentage of civilizations annihilate themselves beyond recovery there must still be a very long tail of ones that only do so at a later date as well as those that do not and those that recover at some later time.

millstone 6y ago

The plan seems to be "to find intelligent civilizations, look for Earth-like planets that can harbor life." How terribly narrow minded. > you'd think the chance that there is intelligent extraterrestrial life in our galaxy seems enormous "And the Earthling rocket ships departed Planet X3, having found no life, only an advanced civilization of extraterrestrial robots." > Another study out of the University of British Columbia looked at the number of sun-like stars in the galaxy and estimated that one in five of them could have an Earth-like planet On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents. Life is surely bigger than Earth-like planets. And Intelligence is surely bigger than Life. In Sagan's book Contact, the hard problem was not finding intelligence, but recognizing it. By the end, we learn that the arrangement of the stars and the digits of pi itself carry a message. This is the level of thinking that our search calls for.

bryanrasmussen 6y ago
> And Intelligence is surely bigger than Life. I don't think your advanced civilization of extraterrestrial robots is doing enough work to establish this particular point. That said I would think looking for earth like planets is not so much just for finding life, but also for the point of making it easier to recognize it as life, and finally hopefully having enough points in common to communicate.
TomMarius 6y ago
There are certain realities that limit where life can be established and flourish, and while different kinds of life might be possible, they're extremely unlikely due to basic physical/chemical constraints, amount of other elements in the universe compared to hydrogen and carbon and oxygen, etc. And even the most inhospitable place on Earth is pretty okay by galactic standards - Earth's magnetic field, characteristics of our star and our planetary configuration being the main reasons.
tsimionescu 6y ago
> On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents. And yet, all life on Earth has the same basic structure. The most likely reason for this is that life only originated once, and in one "place". This observation significantly reduces the probability we should ascribe for life to appear, and/or the specificity of the conditions required. For example, we know for sure that a planet like the Earth today is completely inhospitable to the emergence of life (there has not been an abiogenesis event for billions of years). The other option is that life has emerged in many places/times on Earth, but with the exact same structure. While unlikely, this would suggest that life must have a very specific structure, that at least on Earth-like planets we should also expect RNA and DNA based life at least. This would also suggest that the likelihood of other kinds of life existing is smaller than initially could have been conceived. And even with this assumption, it would still not be clear that life is appearing on Earth today anymore, as the life forms we've looked at seem to have a phylogenetic link with other life (though our methods may be weak if the possibility of abiogenesis were correct). And even if abiogenesis was still occurring on Earth, it would have to be in some remote place in extreme conditions, as we have tried in all regular places with no success. Overall, my belief is that the emergence of life is likely a vastly improbable event, and that we shouldn't expect to "see" a living (or formerly living) being that is not related to life on Earth in the lifetime of the Earth. > And Intelligence is surely bigger than Life. This seems a mystical belief, given all we know of the world.

LatteLazy 6y ago

Isn't the who point of the drake equation to discuss the factors? And most of the factors can't actually be measured until you've met a few dozen other civilisations and compared histories?

jasonlfunk 6y ago

> Of course since no one knows how long intelligent civilizations last, (given our current trajectory, some might guess not very long) These people must have a very short sighted view of history? Our current trajectory for almost everything that matters is positive. Longer life spans, fewer wars, better medicine and technology, average base-level knowledge, etc. Barring some global unavoidable catastrophe, there is no reason to think we are going anywhere very soon.

tsimionescu 6y ago
> Barring some global unavoidable catastrophe, there is no reason to think we are going anywhere very soon. If only we didn't live during a huge ecological disaster that is threatening to destroy the livelihoods of hundreds of millions of people directly, with unforeseeable consequences for the rest of the world; which the major powers of the world are unwilling to act in any significant way to curtail; and which seems to require a re-structuring of the entire world's economy to actually solve... Looking at the world right now, we know one thing for sure: none of the trends we see today will be relevant in 100 years. One way or another, the world will go through massive changes whose scope can't be predicted. One possibility is global warming will continue unabated until we have hundreds of millions of people migrating from rapidly submerging areas (Bangladesh being one of the largest concentrations of population in the world living a few meters above sea levels), most likely followed by some kind of global war to prevent or redirect the massive migrations. Another is that the global economy will be completely re-created to stop the production of greenhouse gases dead in its tracks, almost certainly in a non-capitalist system, since capitalism simply can't deal with externalities. The required political and economic shifts are hard to imagine, and the resulting world is equally hard to predict. And of course, we are still always a few madmen away from nuclear war, with many of the world's most tense regions having nuclear weapons aimed at their enemies. Could global warming start a resource war between India and Pakistan that would lead to them using their arsenals? Could Israel decide to use its illegal nuclear weapons to attack Iran in a "defensive first strike"? Could the US decide that its interests are important enough that, as its soft power wanes, it could launch a bomb at some country to remind everyone of its hard power? Could the Europeans spark a new war, either among themselves or against some common threat, and feel the need to use their nuclear arsenal? Could the Chinese? As long as nuclear weapons exist, they are an ever growing threat. Remember that just in the last few years, the long standing US-Russian non-proliferation treaty was unilaterally ended by the US, signalling a vast increase in the risk of nuclear weapons actually seeing use again.

simonkafan 6y ago

I read the paper and I find it highly unserious how frivolously they assigned some probability to the question how many intelligent civilizations there are in the universe. Their key assumption is: "We assume that if an SP remains in the circumstellar Habitable Zone (HZ) for a time equal to the current age of the Earth it will develop intelligent, communicative life." (page 5 at https://arxiv.org/ftp/arxiv/papers/2004/2004.03968.pdf https://arxiv.org/ftp/arxiv/papers/2004/2004.03968.pdf) Why? Why do you assume a planet will develop intelligent life when it remains in the Habitable Zone long enough? Just because it happend on Earth? And they continue with: "[...] according to the Copernican Principle – we propose that the likelihood of the development of life, and even intelligent life, should be broadly uniformly distributed amongst any suitable habitats" We have no clue how likely it was at Earth that life developed at all. Maybe it was just a chain of many lucky coincidences that happen once in 10 billion years. How is distribution any relevant then?

bhaak 6y ago
With other assumptions, they would arrive at 0 intelligent civilisations in the galaxy. That would make the rest of the paper void. :-) Nobody knows how life is distributed in the galaxy. Assuming that we are not special (the Copernican Principle) is a valid prerequisite. As it neither can be proved or disproved, it's not unserious to just state what the unproven assumptions are.
dahfizz 6y ago
One thing that bothers me is that papers like this always assume alien life will look exactly like life on Earth. It must be the same distance from the sun as us, have water and proteins like us, etc. If we effectively limit the definition of "life" to "the types of organisms we see on Earth", then of course we will never find life anywhere else. Maybe there are aliens that live on a gas giant and they "eat" the lighting rather than food, and their bodies look more like circuitry than the chemical life on Earth. Maybe there is a planet with a very strong magnetic field, and the life there is kind of like an electromagnet. They have bodies high in copper and the current of the ocean moves them through the magnetic field and generates electrical energy. It makes sense that we restrict our search for life forms we know to be possible while we are stuck with limited tools at our disposal. But I don't want us to overlook some amazing discoveries because we have put blinders on.

loudouncodes 6y ago

How can this article, as well as the hundreds of comments here, not acknowledge that all they are doing is solving the Drake Equation for new values they are estimating?

smartmic 6y ago

Civilizations fail. Here is more on that and the related Fermi paradox : http://t3x.org/bits/doomed/index.html http://t3x.org/bits/doomed/index.html

mchusma 6y ago

Issac Arthur's podcast is the best resource on these matters. Amazing work, and makes this paper seem very week. He identifies many possible filters beyond the Drake equation. If you like this sort of discussion, you will almost certainly like the podcast. Relevant playlist https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh8TTOnCgRkLdU https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh...

planetis 6y ago

Im disappointed they did't arrive at 42, but 36

historyremade 6y ago

This is intellicist. Aliens should protest!!

robodale 6y ago

I worry that other far more advanced civilizations out there routinely stamp out any new "pest" civilizations....much like how I handle ant colonies behind my house. They get too large or too close...then I knock them out.