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Galaxy Simulations Offer a New Solution to the Fermi Paradox

169 points by Errorcod3 8y ago

bjornlouser 8y ago
Obviously the aliens wait to make contact until there is only one species left on the planet. We're almost there!
- nkrisc 8y ago
  I don't think the tardigrades are going to be able to respond.
pavel_lishin 8y ago
Is it just me, or did I not catch any new solutions to the paradox in the article?
- agreeer 8y ago
  Not just you. The article just summarized some of the more popular theories.
- eyeundersand 8y ago
  Exactly my thinking. Seems like a whole lot of fluff sans new insight.
  - slowmovintarget 8y ago
    It isn't a new solution, it's a contradiction of the paradox. That is, the initial assumptions of the prevalence and proliferation of life are statistically wrong. If we account for x, y, and z, we get the results we observe today.
- naasking 8y ago
  They link directly to the new paper: https://arxiv.org/abs/1902.04450 https://arxiv.org/abs/1902.04450 Snippet from abstract: > Our steady-state model can constrain the probabilities for an Earth visit by a settling civilization before a given time horizon. These results break the link between Hart's famous "Fact A" (no interstellar visitors on Earth now) and the conclusion that humans must, therefore, be the only technological civilization in the galaxy.
cletus 8y ago
tl;dr it shouldn't take as long as previously thought to colonize the galaxy based on a simulation. That's largely an irrelevant finding that adds nothing to the Fermi Paradox because the time it would take to colonize the galaxy is so small in cosmological terms that shortening it is irrelevant. What's more the authors decided to modeled the suitability of star systems impeding colonization when this seems like it would be largely irrelevant because starfaring civilizations seem highly unlikely to be planet-bound as this is a pretty inefficient use of mass. The Dyson Sphere (Swarm) seems much more likely at which point the only thing of value is the star. The planets are just piles of raw materials ultimately. Obligatory plug for Isaac Arthur who has a series of videos on the Fermi Paradox. Here's an early one [1]. There are 10-20 others that go into particular aspects. [1] https://www.youtube.com/watch?v=rDPj5zI66LA https://www.youtube.com/watch?v=rDPj5zI66LA
SketchySeaBeast 8y ago
If we assume that most stars are in a sort of orbit around the core, wouldn't the stars stay in relatively the same place? And regardless, wouldn't they still require the ability and timing to take advantage of those moments the solar system's get close to each-other? That still requires a monstrous amount of technology and energy, doesn't it?
- YaxelPerez 8y ago
  Stars closer to the core move faster, so it's more like a whirlpool than a rotating disk.
- wongarsu 8y ago
  An lower orbit is faster than a higher orbit (orbits trade speed for height a bit like pendulums). So on long enough timescales your neighbors change as every solar system is on a slightly different orbit. > That still requires a monstrous amount of technology and energy, doesn't it? If we wanted we could spend ~10 years R&D on a practical nuclear pulse drive and send a probe at 10% the speed of light to the nearest solar system. That makes 40 years travel time for the probe and 4 years communication delay. Add some time for acceleration , deceleration and exploration and we might be able to send a colony ship 60 years after the probe left. Another 40 years travel time and we have a colony on another solar system 110 years from now, at a price point attainable for a large corporation or a medium sized country (after all most of the cost is research spread over half a century) Now imagine what a more advanced civilization with more incentives for colonisation could do.
  - SketchySeaBeast 8y ago
    In this scenario who is "we" that invests that time and energy?
    - wongarsu 8y ago
      I think The Expanse had the right idea with a powerful religious organisation like the Mormons. I could also imagine a totalitarian regime doing it to unite their people under a common goal (similar to the space race being a source of national pride especially for the Soviets). Or maybe a billionaire chooses to dedicate his money to such an endeavour (a Bill Gates who loves space as much as Elon Musk). I agree it's unlikely that our civilization does it now. But given some time and a handful of civilizations and it seems like it should happen all the time (even more so if overpopulation or collapsing ecosystems were serious problems for some civilisations)
lukifer 8y ago
My favorite solution: The galaxy is teeming with life, but in the form of quasi-immortal software that lives at such vast timescales, they're as uninterested in talking to us as we would be in talking to a fruit fly. (Imagine Space Ents that say hello, and are perfectly content to wait 10,000 years for a reply.) It may well be that becoming such a life form is the only practical way to deal with the speed-of-light constraint, either in travel or communication.
- joe_the_user 8y ago
  To continue the speculation, such "life" may be what can travel between stars but life such as our may still be common. Indeed, life such as our may be common enough that interstellar life merely takes note of it and moves on since novelty wears off quickly.
  - dsfyu404ed 8y ago
    Like some British ship visiting some pacific island circa 1800 "Yup, just some birds, palm trees and nothing particularly useful here, note the location in the log and move on."
- gloriousduke 8y ago
  I've encountered an idea similar to this: > The transcension hypothesis proposes that a universal process of evolutionary development guides all sufficiently advanced civilizations into what may be called "inner space," a computationally optimal domain of increasingly dense, productive, miniaturized, and efficient scales of space, time, energy, and matter, and eventually, to a black-hole-like destination. https://accelerating.org/articles/transcensionhypothesis.html https://accelerating.org/articles/transcensionhypothesis.htm...
  - Joe-Z 8y ago
    Would you mind dumbing that down for me? As I understand it we'd be living inside a simulation. Isn't that what GP suggested?
coldcode 8y ago
Out of millions of species that have appeared on this planet, only 1 made it to space. It could be most aliens never make it to space.
- contravariant 8y ago
  Although compared to reaching space it's relatively simple to prevent other species from ever reaching space, as the Homo Sapiens may well have done.
- joe_the_user 8y ago
  Every single slightly habitable planet in the galaxy could harbor a species that has gone to it's nearest moons and planets, and we wouldn't be able to tell. Every transmission our species has made is indistinguishable from quantum noise at the distance of Alpha Centauri. In the sense of the Fermi Paradox, zero species on this star have "made it to space".
  - JohnJamesRambo 8y ago
    But one of the tenets of the paradox is so much time has passed you shouldn’t have to work hard to detect alien life, they should have already colonized everywhere. >Even at the slow pace of currently envisioned interstellar travel, the Milky Way galaxy could be completely traversed in a few million years.
    - TheOtherHobbes 8y ago
      Which assumes that we know what "colonised" looks like. The entire premise is rather bizarre. "Let's send out probes that make probes that send out more probes until we've covered the galaxy!" "But... why would anyone do that?" It seems obvious until you think about it - and then it stops being obvious. So you cover your galaxy with probes that keep sending probes back and forth. So what? What have you actually achieved? If you assume massively superhuman intelligence, what are the odds there are more interesting goals for a civilisation to aim for?
hliyan 8y ago
> It’s possible that the Milky Way is partially settled, or intermittently so; maybe explorers visited us in the past, but we don’t remember, and they died out. The solar system may well be amid other settled systems; it’s just been unvisited for millions of years. This, however, does not explain the complete lack of artifacts or observable technological signatures.
- Joe-Z 8y ago
  Oh, but don't forget that one congregation of dust particles that flew by us really fast, which _might_ (who am I kidding - we all know it's 100%!) have been an alien probe. Oumuamua is what it's been called.
  - btilly 8y ago
    An alternate explanation for that is that it was effectively a giant fractal dust bunny left over from the formation of a solar system. The fractal structure explains why it is so light. As for how fast it is traveling, it was traveling at close to the average speed of stars around us. The 25 km/s that we saw is mostly how fast we are traveling, not it. (The Sun bounces up and down through the galactic plane. We are currently "above" it and heading up. We'll next arrive back where we are in about 30 million years.) There might be a lot of objects like that out there. In fact the fact that we randomly saw one suggests that there are many orders of magnitude more of them than we had realized.
    - cpeterso 8y ago
      The PBS Space Time video series, written and hosted by Lehman College astrophysicist Matthew O’Dowd, has a nice analysis of popular 'Oumuamua theories: "'Oumuamua Is Not Aliens" https://www.youtube.com/watch?v=wICOlaQOpM0 https://www.youtube.com/watch?v=wICOlaQOpM0
- Izkata 8y ago
  I like Stargate SG-1's solution to this: Evidence is all around us (both in mythology and ancient artifacts), we just don't recognize it.
bergoid 8y ago
FTA: "Faster-growing, rapacious societies might peter out before they could touch all the stars." I don't get this reasoning. The way I see it: every solar system that gets settled is a fresh roll of the dice. Every newly colonized system increases the odds that at least one of these settlements will not self-destruct. Polynesia is a great analogy. While Easter Island is suffering, Hawaiʻi, Tahiti and hundreds of other islands might still be going strong.
- maze-le 8y ago
  That is if it is somehow economically feasibly for those societies to develop interstellar travel in the first place. When a civilization is occupied with its own struggles and conflicts (the fast-living rapacious ones), they might be incentivized to first exploit local resources before interstellar travel is considered seriously.
thangalin 8y ago
The Percolation Theory reasons that Earth might linger in an uninteresting part of the Milky Way: its galactic backwaters. See: * [1998] http://www.geoffreylandis.com/percolation.htp http://www.geoffreylandis.com/percolation.htp * [2014] https://arxiv.org/abs/1404.0204 https://arxiv.org/abs/1404.0204
- CodeMage 8y ago
  Oh, okay, so we should be fine until the Vogons come.
- 1001101 8y ago
  Percolation theory [1] is touched on in 3-4 pages in The Eerie Silence: Renewing Our Search for Extraterrestrial Intelligence [2] as well. [1] https://en.wikipedia.org/wiki/The_Eerie_Silence https://en.wikipedia.org/wiki/The_Eerie_Silence [2] https://en.wikipedia.org/wiki/Percolation_theory https://en.wikipedia.org/wiki/Percolation_theory
btilly 8y ago
I have a boring solution to the Fermi paradox. It is old, but really, really boring. Start looking at things that are weird about our Solar System and the Earth. Figure out which ones are probably necessary for intelligence. Add those into the Fermi calculation. And see that it is likely that we're the first intelligent life in this galaxy. What are some of those special things? It is not enough to have a planet that has the right ingredients to start life. It is necessary that it's progress not be constantly wiped out by major disasters over a very long time scale. What kinds of disasters? You don't want a supernova going off too close. We have been lucky to avoid that. Our odds were greatly improved by the fact that we spend most of our time out of the galactic plane, away from other stars that could be about to go boom. This is an unusual orbit. You don't want to be hit by too many comets. We've been hit by some, but far, far less than we would have without Jupiter acting like a sweeper to clean up dangerous stuff in our neighborhood. How rare is that? We have cataloged planets in hundreds of other solar systems. We see ones with only rocky planets. Ones with only gas giants. But we're the only one we know of with both gas giants and rocky planets. The only one where the rocky planets wind up protected from most of dinosaur killer kinds of impacts. Oh, and get this one. Without the Moon, the tilt of the Earth's spin is unstable. Without it, in simulations we would wind up with one pole aimed at the Sun and the other not once every few tens of millions of years. Probably not good for the development of intelligent life. Again we don't know how rare this is, but we suspect that it is rather uncommon. Suppose that each of these only happens to one star out of a thousand. Suppose further that there is one more, as yet unidentified, special factor about us that is also required. Again make that a 1/1000 coincidence. That would make the odds good that of the ~250 billion stars in our galaxy, we're the only ones with intelligent life. Or if you do the back of the envelope just with the three that I named, and made them 1/10,000 coincidences, you get the same result. As a sanity check, the fact that no other intelligent life has been observed is evidence that it is unlikely. And given Fermi's argument, it is probably unlikely at least on the scale of 100 billion to one against.
- ars 8y ago
  You also need an ocean.
  - 8y ago
PavlikPaja 8y ago
The problem with the Fermi paradox is that it requires you to assume the existence of spacefaring civilizations, with all the expected technology. The possibilities are just to many, and we only know relatively well our own solar system, we don't know how normal it is (recent observations suggests it could be at least kind of odd) or how normal Earth is. As it is quoted, Earth for us is all there is and it would seem completely normal to us even if for any well educated alien it could look obviously artificial. The Black planet hypothesis: There are planets intentionally cut off the bigger society. Spacefaring civilizations are largely immortal, and would be kept in an evolutionary stasis, so there are planets that are intentionally kept isolated and prisoners are kept on them in a pre galactic stage as a way to keep evolving. Impending doom hypothesis: An immense catastrophe is expected to happen in the general area, and all the surrounding space has been evacuated. Presumed recluse hypothesis: Our solar system is recognized as obviously artificial, yet attempts to communicate are met with no response. We are perceived as unwilling to communicate and intentionally left alone. Planets are primitive hypothesis: More advanced civilizations have no interest in settling planets, planets are seen as primitive as living in a rainforest is to us, while advanced civilizations normally live in artificial habitats. Unpleasant star hypothesis: The solar wind, neutrino flow or other forms of radiation may be disruptive to highly advanced technology, so the sources are avoided unless necessary.
- pavel_lishin 8y ago
  > it requires you to assume the existence of spacefaring civilizations That's one of the variables in the Fermi equation. Set it to zero, and the paradox vanishes.
  - PavlikPaja 8y ago
    Well, yeah. "with all the expected technology" is the important part.
    - pavel_lishin 8y ago
      That's another variable.
nukeop 8y ago
The obvious, but hard to swallow solution to the Fermi paradox: aliens are a product of science-fiction, and don't exist. Not everything we can come up with in thought experiments has a real life counterpart.
- jcoffland 8y ago
  But unlike time travel or flux capacitors aliens do have a real life counter part, us. We know life exists, it's not a stretch to imagine there is more of it.
  - nukeop 8y ago
    Before we can postulate a realistic generalized conclusion, we need a sample size larger than 1. Right now the scientific, rational position on Fermi's paradox is that outside of Earth the universe is completely devoid of life.
    - maze-le 8y ago
      That is one rational position, not THE rational position. I'd say it is the only empiricist position to take, but not all rational arguments are necessarily empiricist.
    - philipkglass 8y ago
      In 1980 was the scientific, rational position that outside of our own Solar System there were no more planets in the universe? I have a hard time calling that a rational position despite the lack of observed exoplanets at that date.
jl6 8y ago
My “boring” “explanation”: the number of alien intelligences is unknowable and irrelevant because interstellar travel and communication are both near as damnit impossible.
- magicnubs 8y ago
  Yeah I wonder if this isn't the simple (and sad) truth. Maybe every intelligent species discovers that the laws of physics are unavoidable hard limits and eventually decide it's a pointless waste of energy to endlessly broadcast signals to other stars and galaxies that are moving, ever faster, further and further away.
deleted 8y ago
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carapace 8y ago
There are lots of aliens. Heck, there were aliens attending certain underground raves in Seattle in the 90's. The Fermi Paradox is about the psychology of humans, not the external universe. As soon as you can psychologically handle communication with other folks it becomes easy to meet and greet them. There are "outreach coordinators" who volunteer to take humans on jaunts within the local neighborhood (nearby star systems, etc.) Our planet experienced a disaster ("dis": separation; "aster": stars; "disaster" is a separation from the stars) a few thousand years ago (Younger Dryas comet) and we've been recovering ever since. Our neighbors have been helping us for all that time. Psychologically our species is an accident victim and we have been recovering from the trauma, which is why our history is so messed up and violent. Normal sentient beings are mensches. We'll get there.
- king_magic 8y ago
  I guess I just don’t understand this kind of comment. Are you being serious? Can you cite any sort of scientifically verified evidence for these claims? It sounds nice and all, but if you’re legitimately being serious, how are we ever supposed to believe this without hard evidence?
  - carapace 8y ago
    > Are you being serious? Yes. (Although by bringing this up in this thread I could be accused of trolling, and it would be hard to defend myself. Sorry.) > Can you cite any sort of scientifically verified evidence for these claims? It depends on what you accept as "scientifically verified evidence". My whole point is the Fermi Paradox is about human epistemology and belief systems, not the actual contents of human experience (which include UFOs and little green men as well as lots of other weird shit.) > It sounds nice and all, but if you’re legitimately being serious, how are we ever supposed to believe this without hard evidence? You're not, evidently. Honestly, I'd settle for folks just getting over their personal problems and returning to a harmonious lifestyle, and if I knew how to do that I would. A lot of the aliens and other people around here are working on the problem, but we're a tough nut to crack and time is running short.
- mprev 8y ago
zackmorris 8y ago
I propose the Morris equation for the odds of alien life finding us: N = ( R * fp * ne * fl * fi * fc * L ) / ( AI * VR * D * S * M ) Where the Drake equation: N = The number of civilizations in the Milky Way Galaxy who detect our electromagnetic emmissions R = Average rate of formation of suitable stars (stars/year) in the Milky Way galaxy fp = Fraction of stars that form planets ne = Average number of habitable planets per star fl = Fraction of habitable planets (ne) where life emerges fi = Fraction of habitable planets with life where intelligent evolves fc = Fraction of planets with intelligent life capable of interstellar communication L = Years a civilization remains detectable Is divided by the karma equation: AI = Whether or not aliens have merged with artificial intelligence, become their own God and are no longer interested in us (tends towards 1) VR = Whether or not aliens have virtual reality akin to the movie The Matrix and live in a hedonistic paradise indefinitely (tends towards 1) D = Number of psychedelic drugs available to aliens that are at least as compelling as actual reality (tends towards infinity) S = Percentage of aliens that reproduce sexually or are able to spend a lifetime living in their parents' basement pondering aliens (let's just say 50%) M = Whether or not aliens use money so contact with extraterrestrials is considered too great a risk (somewhere between 0 and 1) So as with all things, first contact by extraterrestrials is likely dominated by the need to procreate and money.
planck01 8y ago
I think that thinking around the Fermi Paradox has the fatal flaw that we think our current technological boom can be extrapolated. We have the feeling that the Kardashev scale, even type 1, is attainable. I'm more technological pessimistic and think it is not attainable. I think the technological boom will peter off, because of hard insolvable questions limited by nature and energy and money. We are enthusiastic now because of past progress and progress we see we can still make. But we will get in diminishing return time and slow stabilization before too long. And progress will become hard until impossible. Humans will never colonize this galaxy. It's too hard, too expensive, and too pointless. And neither will other intelligent civilizations, of which I guess a small handful at most will exist in the lifetime of our galaxy. Maybe some galaxies do exist where a civilization lives that put everything of their energy on spreading within their galaxies. But even they will not be able to spread to other galaxies. The acceleration of the universe and the extreme distances and nothingness forbids that.
- koboll 8y ago
  >Humans will never colonize this galaxy. It's too hard, too expensive, and too pointless. If we stick around long enough, it will eventually, over a long enough scale, become none of those things. We're 95% of the way, as a species, toward the point of spreading out to such a diaspora that no natural force can eradicate us. Even if we don't end up doing it because of nuclear weapons or mass suicide or some other reason, we would expect at least some other civilizations that reach our level of advancement to reach that last 5% beyond -- unless no other comparable civilizations have ever arisen in the first place.
- ColanR 8y ago
  > too pointless It has seemed to me that we _have_ to colonize the galaxy, if we aren't - as a species - going to be forced to resort to periodic mass genocide of exactly the type discussed in the Marvel Studios Infinity War movie.
  - ccvannorman 8y ago
    This is patently false. Hans Rosling and others have explored the statistics of the population growth on Earth, and unless our course of childbirth and death drastically changes, we will cap out at 9-10 billion. There are many factors, but basically, as poorer nations become middle-class they start having fewer than 2 children per couple on average.
rbanffy 8y ago
The notion we'd settle on planetary surfaces makes assumptions on the anthropology of our offspring. Moving between stars requires us to master living in enclosed habitats for generations. If we do that, why would we bother with planets? We could arrive at the periphery of a system or an accretion disk of a young star, get all the materials to build a couple hundred new habitats and launch them towards the next system. Would we still want to settle on planetary surfaces?
- slfnflctd 8y ago
  This is a huge aspect. We've already got lots of precedent of splits between nomadic vs. agricultural societies. I think we would naturally group ourselves into 'travelers' and 'settlers', with a small amount of migration between the two-- and eventually in the long run, species differentiation.
  - rbanffy 8y ago
    With small populations isolated during the centuries between stops, differentiation will be very fast and could happen within a single longer trip. There are only 10,000 years between wolf and poodle. In order to avoid it, the groups could start the journey with a set of frozen eggs (or static genomes in whatever medium they find convenient) to be reinserted into the population along the trips, as well as extensive genetic matching between the living populations to ensure a viable long-term gene pool. And, of course, it's not unreasonable to expect some groups to engage in active eugenics and direct their evolution so they are better suited to their way of live - nomadic or settler.
b_tterc_p 8y ago
Do we have an estimate for likelihood of noticing earth as a life containing planet as a function of how far away we might imagine ourselves in the galaxy given current methods?
- Guillaume86 8y ago
  I remember reading than from a radio emissions standpoint, we wouldn't detect our activity if it was happening on a planet in the closest star system. I don't know about other methods but very interested too.
fernly 8y ago
Folks, the "Great Filter"[1] is looking us right in the face, in the form of catastrophic climate change[2]. It seems quite a likely hypothesis that any upcoming intelligent species would, like us, ride the horse of fossil fuels right into disaster. [1] https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter [2] http://nymag.com/daily/intelligencer/2017/07/climate-change-earth-too-hot-for-humans-annotated.html http://nymag.com/daily/intelligencer/2017/07/climate-change-...
- ams6110 8y ago
  Climate change won't end life on earth. It may be an extinction event for humans. Personally I think this is unlikely, but so what if it is? There have been extinction events before, and in fact that is why we are dominating the planet instead of the dinosaurs.
bronz 8y ago
i dont know why people think there is a paradox. the way that life springs from barren rock is not known. if we dont know how that works, then we cant assign a probability to it happening on a given planet. people just assume that the probability is very high. it could be next to nothing for all we know, small enough so that even the entire universe only produces one. the paradox is all based on huge assumptions. there is no paradox until we prove that the probability is high. well thats not true, because you need life but you also need intelligence. and again, everyone assumes that if you have life it will eventually become intelligent. and people assume that if life is intelligent it will eventually build space shuttles. its all a huge, huge assumption. look at all the animals that qualify as intelligent. some birds and monkeys are hugely intelligent, but they dont build space shuttles. this shows that intelligence doesnt equal space shuttles and that even when life springs up, and even when it becomes intelligent, it still could be super unlikely that it will build space shuttles. hell, there are even humans that might have never built space shuttles. there are indigenous communities all over the planet that never developed technology and probably never would have. when you live in a warm climate and food is abundant, there may never be a reason to. it is unproven that it is likely at all for space-shuttle level intelligence to spring up from bare earth. there is no paradox. its probably just really unlikely.
8bitsrule 8y ago
On a related note, this recent article explores the idea that life may be inevitable. (An idea going back at least as far as Ilya Prigogine.) https://qz.com/1539551/is-the-universe-pro-life-the-fermi-paradox-can-help-explain/ https://qz.com/1539551/is-the-universe-pro-life-the-fermi-pa... "According to the inevitable life theory, biological systems spontaneously emerge because they more efficiently disperse, or “dissipate” energy, thereby increasing the entropy of the surroundings. In other words, life is thermodynamically favorable."
- scotty79 8y ago
  Still takes a hell lot of time to develop to a point of spreading from one star to another.
lowdest 8y ago
Isaac Arthur has a whole series of podcasts that cover all the current ideas around the Fermi paradox, which ones are more or less likely and why. Really interesting stuff. Here's a link to his Fermi Paradox playlist on Youtube: https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh8TTOnCgRkLdU https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh... He's also got a Soundcloud for audio-only format and a Facebook group.

169 points by Errorcod3 8y ago

bjornlouser 8y ago

Obviously the aliens wait to make contact until there is only one species left on the planet. We're almost there!

nkrisc 8y ago
I don't think the tardigrades are going to be able to respond.

pavel_lishin 8y ago

Is it just me, or did I not catch any new solutions to the paradox in the article?

agreeer 8y ago
Not just you. The article just summarized some of the more popular theories.
eyeundersand 8y ago
Exactly my thinking. Seems like a whole lot of fluff sans new insight.
- slowmovintarget 8y ago
  It isn't a new solution, it's a contradiction of the paradox. That is, the initial assumptions of the prevalence and proliferation of life are statistically wrong. If we account for x, y, and z, we get the results we observe today.
naasking 8y ago
They link directly to the new paper: https://arxiv.org/abs/1902.04450 https://arxiv.org/abs/1902.04450 Snippet from abstract: > Our steady-state model can constrain the probabilities for an Earth visit by a settling civilization before a given time horizon. These results break the link between Hart's famous "Fact A" (no interstellar visitors on Earth now) and the conclusion that humans must, therefore, be the only technological civilization in the galaxy.

cletus 8y ago

tl;dr it shouldn't take as long as previously thought to colonize the galaxy based on a simulation. That's largely an irrelevant finding that adds nothing to the Fermi Paradox because the time it would take to colonize the galaxy is so small in cosmological terms that shortening it is irrelevant. What's more the authors decided to modeled the suitability of star systems impeding colonization when this seems like it would be largely irrelevant because starfaring civilizations seem highly unlikely to be planet-bound as this is a pretty inefficient use of mass. The Dyson Sphere (Swarm) seems much more likely at which point the only thing of value is the star. The planets are just piles of raw materials ultimately. Obligatory plug for Isaac Arthur who has a series of videos on the Fermi Paradox. Here's an early one [1]. There are 10-20 others that go into particular aspects. [1] https://www.youtube.com/watch?v=rDPj5zI66LA https://www.youtube.com/watch?v=rDPj5zI66LA

SketchySeaBeast 8y ago

If we assume that most stars are in a sort of orbit around the core, wouldn't the stars stay in relatively the same place? And regardless, wouldn't they still require the ability and timing to take advantage of those moments the solar system's get close to each-other? That still requires a monstrous amount of technology and energy, doesn't it?

YaxelPerez 8y ago
Stars closer to the core move faster, so it's more like a whirlpool than a rotating disk.
wongarsu 8y ago
An lower orbit is faster than a higher orbit (orbits trade speed for height a bit like pendulums). So on long enough timescales your neighbors change as every solar system is on a slightly different orbit. > That still requires a monstrous amount of technology and energy, doesn't it? If we wanted we could spend ~10 years R&D on a practical nuclear pulse drive and send a probe at 10% the speed of light to the nearest solar system. That makes 40 years travel time for the probe and 4 years communication delay. Add some time for acceleration , deceleration and exploration and we might be able to send a colony ship 60 years after the probe left. Another 40 years travel time and we have a colony on another solar system 110 years from now, at a price point attainable for a large corporation or a medium sized country (after all most of the cost is research spread over half a century) Now imagine what a more advanced civilization with more incentives for colonisation could do.
- SketchySeaBeast 8y ago
  In this scenario who is "we" that invests that time and energy?
  - wongarsu 8y ago
    I think The Expanse had the right idea with a powerful religious organisation like the Mormons. I could also imagine a totalitarian regime doing it to unite their people under a common goal (similar to the space race being a source of national pride especially for the Soviets). Or maybe a billionaire chooses to dedicate his money to such an endeavour (a Bill Gates who loves space as much as Elon Musk). I agree it's unlikely that our civilization does it now. But given some time and a handful of civilizations and it seems like it should happen all the time (even more so if overpopulation or collapsing ecosystems were serious problems for some civilisations)

lukifer 8y ago

My favorite solution: The galaxy is teeming with life, but in the form of quasi-immortal software that lives at such vast timescales, they're as uninterested in talking to us as we would be in talking to a fruit fly. (Imagine Space Ents that say hello, and are perfectly content to wait 10,000 years for a reply.) It may well be that becoming such a life form is the only practical way to deal with the speed-of-light constraint, either in travel or communication.

joe_the_user 8y ago
To continue the speculation, such "life" may be what can travel between stars but life such as our may still be common. Indeed, life such as our may be common enough that interstellar life merely takes note of it and moves on since novelty wears off quickly.
- dsfyu404ed 8y ago
  Like some British ship visiting some pacific island circa 1800 "Yup, just some birds, palm trees and nothing particularly useful here, note the location in the log and move on."
gloriousduke 8y ago
I've encountered an idea similar to this: > The transcension hypothesis proposes that a universal process of evolutionary development guides all sufficiently advanced civilizations into what may be called "inner space," a computationally optimal domain of increasingly dense, productive, miniaturized, and efficient scales of space, time, energy, and matter, and eventually, to a black-hole-like destination. https://accelerating.org/articles/transcensionhypothesis.html https://accelerating.org/articles/transcensionhypothesis.htm...
- Joe-Z 8y ago
  Would you mind dumbing that down for me? As I understand it we'd be living inside a simulation. Isn't that what GP suggested?

coldcode 8y ago

Out of millions of species that have appeared on this planet, only 1 made it to space. It could be most aliens never make it to space.

contravariant 8y ago
Although compared to reaching space it's relatively simple to prevent other species from ever reaching space, as the Homo Sapiens may well have done.
joe_the_user 8y ago
Every single slightly habitable planet in the galaxy could harbor a species that has gone to it's nearest moons and planets, and we wouldn't be able to tell. Every transmission our species has made is indistinguishable from quantum noise at the distance of Alpha Centauri. In the sense of the Fermi Paradox, zero species on this star have "made it to space".
- JohnJamesRambo 8y ago
  But one of the tenets of the paradox is so much time has passed you shouldn’t have to work hard to detect alien life, they should have already colonized everywhere. >Even at the slow pace of currently envisioned interstellar travel, the Milky Way galaxy could be completely traversed in a few million years.
  - TheOtherHobbes 8y ago
    Which assumes that we know what "colonised" looks like. The entire premise is rather bizarre. "Let's send out probes that make probes that send out more probes until we've covered the galaxy!" "But... why would anyone do that?" It seems obvious until you think about it - and then it stops being obvious. So you cover your galaxy with probes that keep sending probes back and forth. So what? What have you actually achieved? If you assume massively superhuman intelligence, what are the odds there are more interesting goals for a civilisation to aim for?

hliyan 8y ago

> It’s possible that the Milky Way is partially settled, or intermittently so; maybe explorers visited us in the past, but we don’t remember, and they died out. The solar system may well be amid other settled systems; it’s just been unvisited for millions of years. This, however, does not explain the complete lack of artifacts or observable technological signatures.

Joe-Z 8y ago
Oh, but don't forget that one congregation of dust particles that flew by us really fast, which _might_ (who am I kidding - we all know it's 100%!) have been an alien probe. Oumuamua is what it's been called.
- btilly 8y ago
  An alternate explanation for that is that it was effectively a giant fractal dust bunny left over from the formation of a solar system. The fractal structure explains why it is so light. As for how fast it is traveling, it was traveling at close to the average speed of stars around us. The 25 km/s that we saw is mostly how fast we are traveling, not it. (The Sun bounces up and down through the galactic plane. We are currently "above" it and heading up. We'll next arrive back where we are in about 30 million years.) There might be a lot of objects like that out there. In fact the fact that we randomly saw one suggests that there are many orders of magnitude more of them than we had realized.
  - cpeterso 8y ago
    The PBS Space Time video series, written and hosted by Lehman College astrophysicist Matthew O’Dowd, has a nice analysis of popular 'Oumuamua theories: "'Oumuamua Is Not Aliens" https://www.youtube.com/watch?v=wICOlaQOpM0 https://www.youtube.com/watch?v=wICOlaQOpM0
Izkata 8y ago
I like Stargate SG-1's solution to this: Evidence is all around us (both in mythology and ancient artifacts), we just don't recognize it.

bergoid 8y ago

FTA: "Faster-growing, rapacious societies might peter out before they could touch all the stars." I don't get this reasoning. The way I see it: every solar system that gets settled is a fresh roll of the dice. Every newly colonized system increases the odds that at least one of these settlements will not self-destruct. Polynesia is a great analogy. While Easter Island is suffering, Hawaiʻi, Tahiti and hundreds of other islands might still be going strong.

maze-le 8y ago
That is if it is somehow economically feasibly for those societies to develop interstellar travel in the first place. When a civilization is occupied with its own struggles and conflicts (the fast-living rapacious ones), they might be incentivized to first exploit local resources before interstellar travel is considered seriously.

thangalin 8y ago

The Percolation Theory reasons that Earth might linger in an uninteresting part of the Milky Way: its galactic backwaters. See: * [1998] http://www.geoffreylandis.com/percolation.htp http://www.geoffreylandis.com/percolation.htp * [2014] https://arxiv.org/abs/1404.0204 https://arxiv.org/abs/1404.0204

CodeMage 8y ago
Oh, okay, so we should be fine until the Vogons come.
1001101 8y ago
Percolation theory [1] is touched on in 3-4 pages in The Eerie Silence: Renewing Our Search for Extraterrestrial Intelligence [2] as well. [1] https://en.wikipedia.org/wiki/The_Eerie_Silence https://en.wikipedia.org/wiki/The_Eerie_Silence [2] https://en.wikipedia.org/wiki/Percolation_theory https://en.wikipedia.org/wiki/Percolation_theory

btilly 8y ago

I have a boring solution to the Fermi paradox. It is old, but really, really boring. Start looking at things that are weird about our Solar System and the Earth. Figure out which ones are probably necessary for intelligence. Add those into the Fermi calculation. And see that it is likely that we're the first intelligent life in this galaxy. What are some of those special things? It is not enough to have a planet that has the right ingredients to start life. It is necessary that it's progress not be constantly wiped out by major disasters over a very long time scale. What kinds of disasters? You don't want a supernova going off too close. We have been lucky to avoid that. Our odds were greatly improved by the fact that we spend most of our time out of the galactic plane, away from other stars that could be about to go boom. This is an unusual orbit. You don't want to be hit by too many comets. We've been hit by some, but far, far less than we would have without Jupiter acting like a sweeper to clean up dangerous stuff in our neighborhood. How rare is that? We have cataloged planets in hundreds of other solar systems. We see ones with only rocky planets. Ones with only gas giants. But we're the only one we know of with both gas giants and rocky planets. The only one where the rocky planets wind up protected from most of dinosaur killer kinds of impacts. Oh, and get this one. Without the Moon, the tilt of the Earth's spin is unstable. Without it, in simulations we would wind up with one pole aimed at the Sun and the other not once every few tens of millions of years. Probably not good for the development of intelligent life. Again we don't know how rare this is, but we suspect that it is rather uncommon. Suppose that each of these only happens to one star out of a thousand. Suppose further that there is one more, as yet unidentified, special factor about us that is also required. Again make that a 1/1000 coincidence. That would make the odds good that of the ~250 billion stars in our galaxy, we're the only ones with intelligent life. Or if you do the back of the envelope just with the three that I named, and made them 1/10,000 coincidences, you get the same result. As a sanity check, the fact that no other intelligent life has been observed is evidence that it is unlikely. And given Fermi's argument, it is probably unlikely at least on the scale of 100 billion to one against.

ars 8y ago
You also need an ocean.
- 8y ago

PavlikPaja 8y ago

The problem with the Fermi paradox is that it requires you to assume the existence of spacefaring civilizations, with all the expected technology. The possibilities are just to many, and we only know relatively well our own solar system, we don't know how normal it is (recent observations suggests it could be at least kind of odd) or how normal Earth is. As it is quoted, Earth for us is all there is and it would seem completely normal to us even if for any well educated alien it could look obviously artificial. The Black planet hypothesis: There are planets intentionally cut off the bigger society. Spacefaring civilizations are largely immortal, and would be kept in an evolutionary stasis, so there are planets that are intentionally kept isolated and prisoners are kept on them in a pre galactic stage as a way to keep evolving. Impending doom hypothesis: An immense catastrophe is expected to happen in the general area, and all the surrounding space has been evacuated. Presumed recluse hypothesis: Our solar system is recognized as obviously artificial, yet attempts to communicate are met with no response. We are perceived as unwilling to communicate and intentionally left alone. Planets are primitive hypothesis: More advanced civilizations have no interest in settling planets, planets are seen as primitive as living in a rainforest is to us, while advanced civilizations normally live in artificial habitats. Unpleasant star hypothesis: The solar wind, neutrino flow or other forms of radiation may be disruptive to highly advanced technology, so the sources are avoided unless necessary.

pavel_lishin 8y ago
> it requires you to assume the existence of spacefaring civilizations That's one of the variables in the Fermi equation. Set it to zero, and the paradox vanishes.
- PavlikPaja 8y ago
  Well, yeah. "with all the expected technology" is the important part.
  - pavel_lishin 8y ago
    That's another variable.

nukeop 8y ago

The obvious, but hard to swallow solution to the Fermi paradox: aliens are a product of science-fiction, and don't exist. Not everything we can come up with in thought experiments has a real life counterpart.

jcoffland 8y ago
But unlike time travel or flux capacitors aliens do have a real life counter part, us. We know life exists, it's not a stretch to imagine there is more of it.
- nukeop 8y ago
  Before we can postulate a realistic generalized conclusion, we need a sample size larger than 1. Right now the scientific, rational position on Fermi's paradox is that outside of Earth the universe is completely devoid of life.
  - maze-le 8y ago
    That is one rational position, not THE rational position. I'd say it is the only empiricist position to take, but not all rational arguments are necessarily empiricist.
  - philipkglass 8y ago
    In 1980 was the scientific, rational position that outside of our own Solar System there were no more planets in the universe? I have a hard time calling that a rational position despite the lack of observed exoplanets at that date.

jl6 8y ago

My “boring” “explanation”: the number of alien intelligences is unknowable and irrelevant because interstellar travel and communication are both near as damnit impossible.

magicnubs 8y ago
Yeah I wonder if this isn't the simple (and sad) truth. Maybe every intelligent species discovers that the laws of physics are unavoidable hard limits and eventually decide it's a pointless waste of energy to endlessly broadcast signals to other stars and galaxies that are moving, ever faster, further and further away.

deleted 8y ago

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carapace 8y ago

There are lots of aliens. Heck, there were aliens attending certain underground raves in Seattle in the 90's. The Fermi Paradox is about the psychology of humans, not the external universe. As soon as you can psychologically handle communication with other folks it becomes easy to meet and greet them. There are "outreach coordinators" who volunteer to take humans on jaunts within the local neighborhood (nearby star systems, etc.) Our planet experienced a disaster ("dis": separation; "aster": stars; "disaster" is a separation from the stars) a few thousand years ago (Younger Dryas comet) and we've been recovering ever since. Our neighbors have been helping us for all that time. Psychologically our species is an accident victim and we have been recovering from the trauma, which is why our history is so messed up and violent. Normal sentient beings are mensches. We'll get there.

king_magic 8y ago
I guess I just don’t understand this kind of comment. Are you being serious? Can you cite any sort of scientifically verified evidence for these claims? It sounds nice and all, but if you’re legitimately being serious, how are we ever supposed to believe this without hard evidence?
- carapace 8y ago
  > Are you being serious? Yes. (Although by bringing this up in this thread I could be accused of trolling, and it would be hard to defend myself. Sorry.) > Can you cite any sort of scientifically verified evidence for these claims? It depends on what you accept as "scientifically verified evidence". My whole point is the Fermi Paradox is about human epistemology and belief systems, not the actual contents of human experience (which include UFOs and little green men as well as lots of other weird shit.) > It sounds nice and all, but if you’re legitimately being serious, how are we ever supposed to believe this without hard evidence? You're not, evidently. Honestly, I'd settle for folks just getting over their personal problems and returning to a harmonious lifestyle, and if I knew how to do that I would. A lot of the aliens and other people around here are working on the problem, but we're a tough nut to crack and time is running short.
mprev 8y ago

zackmorris 8y ago

I propose the Morris equation for the odds of alien life finding us: N = ( R * fp * ne * fl * fi * fc * L ) / ( AI * VR * D * S * M ) Where the Drake equation: N = The number of civilizations in the Milky Way Galaxy who detect our electromagnetic emmissions R = Average rate of formation of suitable stars (stars/year) in the Milky Way galaxy fp = Fraction of stars that form planets ne = Average number of habitable planets per star fl = Fraction of habitable planets (ne) where life emerges fi = Fraction of habitable planets with life where intelligent evolves fc = Fraction of planets with intelligent life capable of interstellar communication L = Years a civilization remains detectable Is divided by the karma equation: AI = Whether or not aliens have merged with artificial intelligence, become their own God and are no longer interested in us (tends towards 1) VR = Whether or not aliens have virtual reality akin to the movie The Matrix and live in a hedonistic paradise indefinitely (tends towards 1) D = Number of psychedelic drugs available to aliens that are at least as compelling as actual reality (tends towards infinity) S = Percentage of aliens that reproduce sexually or are able to spend a lifetime living in their parents' basement pondering aliens (let's just say 50%) M = Whether or not aliens use money so contact with extraterrestrials is considered too great a risk (somewhere between 0 and 1) So as with all things, first contact by extraterrestrials is likely dominated by the need to procreate and money.

planck01 8y ago

I think that thinking around the Fermi Paradox has the fatal flaw that we think our current technological boom can be extrapolated. We have the feeling that the Kardashev scale, even type 1, is attainable. I'm more technological pessimistic and think it is not attainable. I think the technological boom will peter off, because of hard insolvable questions limited by nature and energy and money. We are enthusiastic now because of past progress and progress we see we can still make. But we will get in diminishing return time and slow stabilization before too long. And progress will become hard until impossible. Humans will never colonize this galaxy. It's too hard, too expensive, and too pointless. And neither will other intelligent civilizations, of which I guess a small handful at most will exist in the lifetime of our galaxy. Maybe some galaxies do exist where a civilization lives that put everything of their energy on spreading within their galaxies. But even they will not be able to spread to other galaxies. The acceleration of the universe and the extreme distances and nothingness forbids that.

koboll 8y ago
>Humans will never colonize this galaxy. It's too hard, too expensive, and too pointless. If we stick around long enough, it will eventually, over a long enough scale, become none of those things. We're 95% of the way, as a species, toward the point of spreading out to such a diaspora that no natural force can eradicate us. Even if we don't end up doing it because of nuclear weapons or mass suicide or some other reason, we would expect at least some other civilizations that reach our level of advancement to reach that last 5% beyond -- unless no other comparable civilizations have ever arisen in the first place.
ColanR 8y ago
> too pointless It has seemed to me that we _have_ to colonize the galaxy, if we aren't - as a species - going to be forced to resort to periodic mass genocide of exactly the type discussed in the Marvel Studios Infinity War movie.
- ccvannorman 8y ago
  This is patently false. Hans Rosling and others have explored the statistics of the population growth on Earth, and unless our course of childbirth and death drastically changes, we will cap out at 9-10 billion. There are many factors, but basically, as poorer nations become middle-class they start having fewer than 2 children per couple on average.

rbanffy 8y ago

The notion we'd settle on planetary surfaces makes assumptions on the anthropology of our offspring. Moving between stars requires us to master living in enclosed habitats for generations. If we do that, why would we bother with planets? We could arrive at the periphery of a system or an accretion disk of a young star, get all the materials to build a couple hundred new habitats and launch them towards the next system. Would we still want to settle on planetary surfaces?

slfnflctd 8y ago
This is a huge aspect. We've already got lots of precedent of splits between nomadic vs. agricultural societies. I think we would naturally group ourselves into 'travelers' and 'settlers', with a small amount of migration between the two-- and eventually in the long run, species differentiation.
- rbanffy 8y ago
  With small populations isolated during the centuries between stops, differentiation will be very fast and could happen within a single longer trip. There are only 10,000 years between wolf and poodle. In order to avoid it, the groups could start the journey with a set of frozen eggs (or static genomes in whatever medium they find convenient) to be reinserted into the population along the trips, as well as extensive genetic matching between the living populations to ensure a viable long-term gene pool. And, of course, it's not unreasonable to expect some groups to engage in active eugenics and direct their evolution so they are better suited to their way of live - nomadic or settler.

b_tterc_p 8y ago

Do we have an estimate for likelihood of noticing earth as a life containing planet as a function of how far away we might imagine ourselves in the galaxy given current methods?

Guillaume86 8y ago
I remember reading than from a radio emissions standpoint, we wouldn't detect our activity if it was happening on a planet in the closest star system. I don't know about other methods but very interested too.

fernly 8y ago

Folks, the "Great Filter"[1] is looking us right in the face, in the form of catastrophic climate change[2]. It seems quite a likely hypothesis that any upcoming intelligent species would, like us, ride the horse of fossil fuels right into disaster. [1] https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter [2] http://nymag.com/daily/intelligencer/2017/07/climate-change-earth-too-hot-for-humans-annotated.html http://nymag.com/daily/intelligencer/2017/07/climate-change-...

ams6110 8y ago
Climate change won't end life on earth. It may be an extinction event for humans. Personally I think this is unlikely, but so what if it is? There have been extinction events before, and in fact that is why we are dominating the planet instead of the dinosaurs.

bronz 8y ago

i dont know why people think there is a paradox. the way that life springs from barren rock is not known. if we dont know how that works, then we cant assign a probability to it happening on a given planet. people just assume that the probability is very high. it could be next to nothing for all we know, small enough so that even the entire universe only produces one. the paradox is all based on huge assumptions. there is no paradox until we prove that the probability is high. well thats not true, because you need life but you also need intelligence. and again, everyone assumes that if you have life it will eventually become intelligent. and people assume that if life is intelligent it will eventually build space shuttles. its all a huge, huge assumption. look at all the animals that qualify as intelligent. some birds and monkeys are hugely intelligent, but they dont build space shuttles. this shows that intelligence doesnt equal space shuttles and that even when life springs up, and even when it becomes intelligent, it still could be super unlikely that it will build space shuttles. hell, there are even humans that might have never built space shuttles. there are indigenous communities all over the planet that never developed technology and probably never would have. when you live in a warm climate and food is abundant, there may never be a reason to. it is unproven that it is likely at all for space-shuttle level intelligence to spring up from bare earth. there is no paradox. its probably just really unlikely.

8bitsrule 8y ago

On a related note, this recent article explores the idea that life may be inevitable. (An idea going back at least as far as Ilya Prigogine.) https://qz.com/1539551/is-the-universe-pro-life-the-fermi-paradox-can-help-explain/ https://qz.com/1539551/is-the-universe-pro-life-the-fermi-pa... "According to the inevitable life theory, biological systems spontaneously emerge because they more efficiently disperse, or “dissipate” energy, thereby increasing the entropy of the surroundings. In other words, life is thermodynamically favorable."

scotty79 8y ago
Still takes a hell lot of time to develop to a point of spreading from one star to another.

lowdest 8y ago

Isaac Arthur has a whole series of podcasts that cover all the current ideas around the Fermi paradox, which ones are more or less likely and why. Really interesting stuff. Here's a link to his Fermi Paradox playlist on Youtube: https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh8TTOnCgRkLdU https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh... He's also got a Soundcloud for audio-only format and a Facebook group.