25 ms·

Dissolving the Fermi Paradox

189 points by laurex 8y ago

e67f70028a46fba 8y ago
> If this is right – and we can debate exact parameter values forever, but it’s hard to argue with their point-estimate-vs-distribution-logic – then there’s no Fermi Paradox. It’s done, solved, kaput. this makes no sense at all: whether or not there is a fermi paradox absolutely depends on the parameters "we can argue about"
- OscarCunningham 8y ago
  Perhaps it be accurate to say the given our current knowledge about the parameters there's not currently a Fermi paradox, but if we gained more information about the parameters then a Fermi paradox could arise in the future.
  - rad88 8y ago
    But nothing at all is really known about "length of time for which such civilizations release detectable signals into space". It's somewhere between a few decades or so and 10 billion years?
    - OscarCunningham 8y ago
      Sure, which is one of the reasons why we don't currently have a Fermi paradox.
      - EthanHeilman 8y ago
        To me the Fermi Paradox isn't really a paradox it is framework for thinking about the problem. This research fits into that framework and provides an interesting new argument that the great filter is more likely to be in our past rather than our future.
    - bena 8y ago
      IIRC, we're already going dark. The amount of "noise" we broadcast into space is diminishing. If other civilizations roughly follow the progress of our own, that could mean that the window a civilization has to be detected is something like 100 - 200 years.
  - jandrese 8y ago
    It all comes down to trying to draw a line from a single point. We don't have enough information to even make an educated guess at this point. IMHO the Fermi paradox has one flawed assumption: that interstellar travel for the purposes of colonization would be possible and desirable. If this is not the case then there is no paradox, everybody is in their solar system happily doing whatever it is they do all day.
    - bena 8y ago
      Exactly. To transfer something between Earth and the nearest star would require about 8 years. Fuck having a pen pal. You'd also need the energy to propel something to the speed of light. Is it even worth it?
      - neaden 8y ago
        I would think so, for an advanced enough civilization certainly you could expect to see something like Bracewell probes getting sent out to go say hi without spending too many resources.
        Retric 8y ago
        Sending 1 probe might be low resources. Try sending 1 probe to every star ever 10,000 years. Because without that the odds of any probe being near us is rather limited. As to self replicating probes that's freaking dangerous. Get something wrong and the universe becomes a very hostile place. PS: In terms of cost consider the % of humanity's GDP spent on SETI projects. Now consider those at least have the possibility of some benefit in your lifetime. Extra Solar probes are unlikely to get much in the way of resource investment from most civilizations.
        bena 8y ago
        He said "for the purposes of colonization". That means sending people out. We would be sending people on one-way trips, for better or worse. You'd likely never hear from them again. As to just sending out Bracewells to say "Hi", why? Once again, the return on a response is very long and not guaranteed. And without a response, what's the point?
pfortuny 8y ago
Wilmott has a simpler way of explaining it: in a magician’s show, what are the odds that he guesses your card right? The question makes no sense because there is no plausible model: he may willingly decide to guess wrong, for example, or the trick may consist in making you forget the card or any other thing. Assigning probabilities without a real model is just hubris, no more.
- zentiggr 8y ago
  But it is human nature to speculate, to have an opinion no matter how unfounded. Personally, I think the chance of encountering another civilization is exactly [0,1]. Pending data to adjust that range.
- whatshisface 8y ago
  You could go to ten thousand magic shows and write down the result of the card guessing each time. Then, based on those probabilities, you could win on average a betting game between audience members about the results of future tricks. No model required.
ravenstine 8y ago
You can calculate all the probabilities you want all day and night, but there's still no evidence. Until we have a frequency of how often life occurs, rather than a single occurrence, speculated probability doesn't mean anything. Especially when we can't even create life in a lab. (If I remember correctly, we've been able to create amino acids using early-Earth conditions, but we haven't really been able to create something like RNA.) The Fermi Paradox hasn't been "dissolved" in any way. It's a response to the idea that the universe is teaming with life. The paradox remains unchanged until we find a credible signal, or we create life in a lab under naturalistic conditions.
- AnimalMuppet 8y ago
  Even if we create life in a lab under naturalistic conditions, that doesn't answer the question. How often do those conditions occur on planets in the universe? We need an actual number. How often does life arise given those conditions? We need an actual number for that, too.
  - deleted 8y ago
    [deleted]
  - a_t48 8y ago
    Also, what if there are other conditions life can start under?
    - AnimalMuppet 8y ago
      And what are they? And how probable are those conditions? And how often does life start under those conditions?
      - TeMPOraL 8y ago
        And what is life? Does it have to be DNA-based replicators? Just carbon-based? Matter-based?
- 8y ago
s-shellfish 8y ago
The Fermi Paradox, to me, is more a philosophical question about the destructive nature of humanity, than it is actually talking about alien civilization. Points of note are 'what is the bottleneck to traveling outside of the space we inhabit?'. Why does one ask the question 'why don't we see life everywhere?'. Lately, some of the time I see this as a metaphor for 'what is the dilemma with broadening horizons?' There could be alien life, there could not be. It's interesting to think about for a while but sometimes I think it is talking about something deeper than the existence of aliens and outer space. Philosophical question about the nature of existence.
thaumaturgy 8y ago
The actual paper, linked from the top of this article, is very readable and I'd recommend taking the time for it. In summary, the traditional approach to the Drake Equation has been to assign fixed values to each polynomial, sometimes an ass-pull and sometimes based off of best estimates from the observable universe. i.e., "0.1 x 0.1 x 0.1 x 0.1..." What these researchers did instead is try to account for the uncertainty of various parameters. They gave each polynomial values in the range of [0, 0.2] for example, ran Monte Carlo simulations on that, and came up with an empty universe 21.45% of the time. To put it another way: we consider it a certainty that some worlds will bear life, and a certainty that some of that life will develop into intelligent civilizations, and a certainty that some of those intelligent civilizations will explore their local system, and a certainty that some of those explorers will develop into massive hyper-intelligent, technologically-advanced, galaxy-spanning species. But we haven't got enough information to be certain about any of those within any reasonable order of magnitude. The probability of any one of those may in fact lie so close to 0 that it solves the Fermi Paradox. FWIW (and it's worth basically nothing), this has been my preferred solution to the Fermi Paradox for a long time now, and it's nice to have this paper to cite when it comes up in the future. I figured that it took Earth 4.5 billion years to produce humans, and humans are only barely space-faring at this point and I'm not certain we'll ever make it out of our solar system. Countless species have appeared and gone extinct in the meantime. It seems far from certain, to me, that evolution necessarily leads to intelligent life, and if I remember right, the latest thinking from evolutionary biologists supports this -- suggesting that modern human intelligence is largely accidental, rather than a byproduct of evolution. The age of the universe would seem to suggest that there's been time for at least a few other worlds to develop intelligent life even at very slow, unlucky paces, but then again, at astronomical time scales the universe has been too violent up until recently to foster that kind of development. The Fermi Paradox seems to have captured a lot of interest from people who like sci-fi and want to think about all kinds of fantastic ideas on why we appear to be alone. Is there a Great Filter? Is this a simulation? Are we in some kind of super-advanced stellar nursery? It's like nerd sniping (https://www.xkcd.com/356/ https://www.xkcd.com/356/) for a particular sort of nerd.
- jerf 8y ago
  I have no idea why, as I write this, the parent is greying out. It's the only reasonable comment on the article as I write this. I know you're really not supposed to tell people they need to read the article on HN, but the paper underlying the article may be the least understood primary source I've ever seen posted to Hacker News. (This beats out the previous record holder, monad tutorials based around an actively incorrect metaphor.) This is not just a standard reiteration of the Fermi Paradox with somebody's new numbers pulled out of the air. It is a legitimately interesting analysis of the problem as a whole. Read the article and/or the underlying paper, carefully, before just reciting the Standard Cant Against the Fermi Paradox, OK? (And downvoting the only person giving a decent explanation of it.) The Standard Cant is encompassed and superseded by the paper in question, with mathematics.
madeuptempacct 8y ago
As of today, we wouldn't be able to detect a same-tech-level civilization even at the closest star with the amount of effort we have given this, so there is no paradox in my mind.
- joe_the_user 8y ago
  Agreed, strongly. The Fermi problem is a speculative theory based on extrapolating human civilization's use of energy to stellar levels (various hypothetical civilization "types" etc). It's plausible life at the scale of earth could be common, based on the principle of our natural non-uniqueness. So the simplest explanation is the speculative extrapolation to stellar energy uses is wrong - human already are more destroying themselves with excess energy use than preparing for any next stage, just as one datum.
- roywiggins 8y ago
  All it takes is one sufficiently early civilization that goes full Neumann-replicator and decides to colonize every system it can for them to have already arrived here long ago. The fact remains that it seems like they didn't, unless they were very careful boy scouts and left no trace.
  - nv-vn 8y ago
    There are so many variables. For example, if they can't travel faster than the speed of light, they might not even think it's worth colonizing. They could also be on scales vastly different from our own, as microbes or as planets. We wouldn't even know what to look for in interstellar communications, let alone have the ability to make sense of anything they send. Our entire "search" has come with the assumption that alien life is going to communicate with radio waves, use sight (in the same range as our own), be similar in size to us, etc.
    - roywiggins 8y ago
      It just takes one weirdo civilization that decides to put up Ozymandias-style monuments to themselves everywhere- they don't even need to do it themselves. They can fire off a few Von Neumann probes and let them do the work to carve Mount Rushmores into every rocky body they can find. It's not much weirder than things humans get up to, and if spacefaring civilizations that can build such probes are common at all (even if short-lived), you might expect at least one of them to have initiated such a project and been successful enough to have built a giant "we wuz here" radioactive pyramid on the moon. Evidently, none of them did- and depending on how many there were, this is either unsurprising or deeply unlikely.
neals 8y ago
So, my fellow HN dreamers... Would you rather be the first or the last civilization in existence?
- lainga 8y ago
  First, so I can show up in the 3rd or 4th installment of a future civilization's video game franchise as an "Ancient One" and speak in hexameter.
  - vkhorikov 8y ago
    Also first so I can introduce a Reaper and make sure no other civilization can advance too much
- TeMPOraL 8y ago
  The middle one. So that we have plenty of younger civilizations to teach and kick around the block if they misbehave. But also so that we have some Ancient Ruins to discover and learn about Meaning of Life from, triggering all the good feels I usually get at this point when watching sci-fi shows.
- squirrelicus 8y ago
  I believe aliens have no reason to not genocide us immediately upon discovering us, so I'd rather be the only civilization. But to answer your question, absolutely the first. That way, if we are more benevolent than the Machiavellian necessity, we will either pioneer an improbable United Federation of Planets or be eradicated due to our idealism and naivete.
jasonkolb 8y ago
I've been listening to the "3 Body Problem" trilogy by Cixin Liu. I'd highly recommend it because not only is it some mind blowing sci-fi, but it also contains one of the most interesting solutions to the Fermi paradox that I've ever seen. I don't want to give anything away because the books are a real treat if you're like me, but the explanation is based on game theory and actually makes a ton of sense. Highly recommended.
- garmaine 8y ago
  Try the Revelation Space series for a better, and earlier take on the idea. The 3 body problem is masquerading as hard SF but isn’t. The author totally misunderstands physics, astronomy, and space faring technology. I hated the books, personally, and don’t see why they are so hyped.
jhallenworld 8y ago
I find the argument that advanced growing alien civilizations would construct "Dyson Swarms" pretty convincing. These structures have the huge advantage that no new physics is required- we could start building ours now with today's technology. They would look like infrared point sources. Sadly none detected yet: https://medium.com/starts-with-a-bang/dyson-spheres-the-ultimate-alien-megastructures-are-missing-from-the-galaxy-447f5f87c2dc https://medium.com/starts-with-a-bang/dyson-spheres-the-ulti...
- canhascodez 8y ago
  The SNR to Mars is not great at the best of times. We no longer radiate a great deal of high-power analog signals, because those are not efficient. Space is noisy, digital signals look very much like noise, and radiating to space is not usually the most efficient thing to do if you can avoid it. Our chances of detecting our own planet even from the nearest star would be pretty minimal. Perhaps someone might be able to explain to me why we postulate being able to detect extrasolar aliens.
  - Chris_Chambers 8y ago
    A Dyson swarm essentially attempts to completely surround a star with solar panels. Infrared wavelengths would then be uncontrollably radiated out into space by the overheating solar panels.
    - canhascodez 8y ago
      Yes, I'm aware. How many of those do you think you could hide in a ten-light-year circle around Earth, and how long do you think it would be before we were able to find them? To a first approximation, the only things that we can see at stellar scales are stars, and all of the discussions on this topic seem to revolve around detecting radio transmissions. This page[0] gives pretty pessimistic numbers for the maximum SNR to Mars. There seems to be some massive disconnect between what people are looking for and what we are currently emitting, or what we might expect an advanced species to be emitting. And my assumption in these cases is that it's substantially more likely that I am a fool and missing something important rather than that everyone else is. [0] http://www.astrosurf.com/luxorion/qsl-mars-communication3.htm http://www.astrosurf.com/luxorion/qsl-mars-communication3.ht...
thomk 8y ago
I know everything I know about the Fermi Paradox from this video (and part 2): https://www.youtube.com/watch?v=sNhhvQGsMEc https://www.youtube.com/watch?v=sNhhvQGsMEc That YouTube channel is awesome by the way. Say goodbye to the rest of your afternoon!
microtherion 8y ago
Previous discussions here: https://news.ycombinator.com/item?id=14686687 https://news.ycombinator.com/item?id=14686687 And here: https://news.ycombinator.com/item?id=17302924 https://news.ycombinator.com/item?id=17302924
based2 8y ago
https://en.wikipedia.org/wiki/Gamma-ray_burst https://en.wikipedia.org/wiki/Gamma-ray_burst
tjradcliffe 8y ago
"Maybe people intuitively figured out what was up (one of the parameters of the Drake Equation must be much lower than our estimate) but stopped there and didn’t bother explaining the formal probability argument." There's no "intuitively" about it. We know from the data available that the probability of machine-building general intelligence of the kind that is unique to humans on Earth is fantastically unlikely to arise. It depends on a confluence of completely unrelated selective pressures: one on tool-making, one on social cooperation, and one on continuous mate competition/selection. There is good evidence that all of those forces are important to specifically human--not dolphin or bird or whatever--intelligence on Earth, and without any one of them we'd still be fairly handy monkey-creatures banging rocks around. As well as a theoretical understanding, we have empirical data. We can ask, "If something is at all probable how many times will it have evolved on Earth?" Eyes, for example, have evolved independently multiple times, based on differences in retinal biochemistry. Wings and fins and legs have also evolved many times across an incredible diversity of species. This tells us that things that are easy to evolve have evolved multiple times in Earth's history. Specifically human, machine-building intelligence has evolved exactly once. This is strong evidence that it has an enormously low probability. Once you've realized that one of the parameters in the Drake equation is incredibly small, the Silent Universe is no longer surprising. And both empirically and theoretically, the probability of evolving specifically human, machine-building intelligence is incredibly small. However, I have never met anyone enamoured of Fermi's Paradox who gives any credence to this, which is why no attempt to resolve the paradox will ever have any effect on the discussion. This is in general the case with so-called paradoxes: no matter how many times they are clearly and simply resolved, people who want there to be paradoxes will pretend the resolution doesn't exist, or will deliberately misrepresent it as a non-solution. Or they will present some other non-solution as more compelling, even when the solution presented makes those non-solutions unnecessary.
rossdavidh 8y ago
This whole idea of "dissolving" the Fermi paradox seems to be missing the point. Everyone knows that we have, in fact, not observed an alien civilization, so one of the factors in the Drake equation (or one we should have put in) is responsible. But, is it that there is very little chance of life evolving, or intelligence? Or is it that intelligence tends to be short lived? Or is it because long-lived intelligence uses methods of communication we cannot observe, and is responsible enough not to colonize all the good planets? The consequences for us are large, depending on which one of those it is. Merely saying "well it's not that surprising that one of those factors is tiny" is not really relevant to the question of, which factor is it that is tiny?
- thaumaturgy 8y ago
  This is addressed in the paper. They estimate that the greatest uncertainties lie in the past terms of the Drake Equation, ergo that there is no evidence of some great threat to the continued advancement of human civilization.
  - bryanrasmussen 8y ago
    Here would seem to be the limit of Bayesian analytics bridging the causal gap.
- danShumway 8y ago
  No, what the article is saying is that when you rely on distributions of outcomes from the Drake equation rather than averages, it's much more likely that you'll get tiny results. You don't need extremely low values in the Drake equation to end up with nearly no aliens. It's actually kind of likely that we're (close to) alone, even without a crazy complicated theory to justify one of the values being nearly zero. This is missing the point that many people do treat the Fermi Paradox like it's a real paradox - like there's some kind of fundamental universal principle that has to almost universally block out all life or all communication. The article is saying you don't need it. It's good enough to say "well, life might just be sort of uncommon, and even in that scenario we shouldn't be surprised that we got a very low roll." That is a surprising conclusion. No, we don't know the exact cause, but it means that the Fermi Paradox might not be a paradox, in the sense that it doesn't directly contradict all of our priors. Think of it like the difference between saying, "Trump won the election because we fundamentally don't understand how democracy works in practice", and "Trump won the election because he had a 1 and 5 chance of winning, and sometimes 20% chance events happen."
sebringj 8y ago
The laws of physics are not localized to earth and yet we see life on earth among countless other possible earths with extreme immense distances between them that light (communication) takes thousands if not millions of years to reach. We see life evolving in the heat vents at the bottom of the ocean along with entirely different paths of evolution to create an eye. Why is this a mystery we have not seen intelligent life? Earths may be frequent and life as well but intelligent life capable of communicating through light AND close enough to communicate may be very very rare. After all, we are only here because the dominant dinosaurs with tiny brains died out changing the rules. In other words, I don't know but intelligent life isn't necessarily the normal end game.
- Klathmon 8y ago
  But part of the paradox is that "universe time" is so monumentally longer than "human time". Even if only a fraction of a fraction of a fraction of all life make it to what we could call "intelligence", then those beings are most likely millions or billions of years "ahead" of us, or won't be intelligent for millions or billions of years from now. At those timescales, even things millions of light-years away are "within reach" of some kind of contact, unless there is something making it impossible (like all intelligent life snuffs itself out given enough time). This is easily one of my favorite things to just think about.
  - gowld 8y ago
    you don't need to "snuff out" life to make it undetectable to us, you just need something that prevents life from getting complex enough for interstellar travel. It's quite plausible that live ebbs and flows (like it has on Earth), but never gets large enough and powerful enough to be detected at remote locations subject to inverse-square signal dissipation.
  - sebringj 8y ago
    I think that's a pretty good point. The vastness of space should be changed to the vastness of space-time which then makes it feel even less likely to find intelligent life which is a little sad.
ared38 8y ago
> Why didn’t anyone think of this before? Anyone that's read even the intro section of the Fermi paradox Wikipedia page already has: "There have been many attempts to explain the Fermi paradox ... suggesting that intelligent extraterrestrial life is extremely rare". The paper just formalizes that by demonstrating we can arrive at low enough expected numbers of aliens (namely 0) with reasonable inputs to the drake equation. > Imagine we knew God flipped a coin. If it came up heads, He made 10 billion alien civilization. If it came up tails, He made none besides Earth. This occludes a lot more than it illuminates. Although the end section of the paper uses the bayesian inference Sniffnoy hinted at, the graphs SSC used (and his analysis of the papers results) come from the earlier section of the paper that still use the "chance of aliens per star" model. Even the bayesian part merely refines this probability based on observations; it's hardly "the wrong way to think about it" as SSC claims.
lisper 8y ago
TL;DR: expected values can be very improbable. The expected value of a Powerball ticket is >0, and in fact by increasing the amount of the prize the expected value can be made arbitrarily large. But the probability that the actual value will be >0 is very nearly zero. And most importantly: that probability does not change as the prize money (and hence the expected value) increases. No matter how big the prize is, you will nonetheless almost certainly not win.
wilg 8y ago
Question for someone smarter than me: is this a similar argument to this[1] 1985 paper (referenced by Wikipedia in the "criticism of logical basis" section[2] on the Fermi Paradox article)? [1] http://adsabs.harvard.edu/abs/1985Icar...62..518F http://adsabs.harvard.edu/abs/1985Icar...62..518F [2] https://en.wikipedia.org/wiki/Fermi_paradox#Criticism_of_logical_basis https://en.wikipedia.org/wiki/Fermi_paradox#Criticism_of_log...
- vlasev 8y ago
  No. This 1985 paper you reference talks about a logical argument for why there is no paradox, whereas the discussed paper is talking about how the uncertainty in the parameters is enough to yield something that is not a paradox.
DaveInTucson 8y ago
For me, the problem with the Fermi paradox is that we only have one poorly understood and incompletely documented example of a planet with intelligent life from which to draw conclusions. Beyond that: * How many habitable planets are out there? We're just now starting to get data on this, there might be a lot * Of those, how many develop life? * Of those that develop life, how many develop intelligent life? * Of those that develop intelligent life, how many advance to the point where they're capable of interstellar travel? How many are interested in interstellar travel? * What if FTL travel is simply not possible? STL interstellar travel could basically be a one-way trip. Maybe most (or all) alien civilizations are unwilling to explore beyond a few light years. * What is the lifetime of a space faring civilization? maybe all the alien civilizations just died out before they explored very far.
- Klathmon 8y ago
  Widen your idea of life. What if another species has figured out a way around death? What if the idea of a single "life" isn't really a thing, and alien lifeforms instead live as a single "consciousness" among them all forever alive. Then the idea of spending millions or billions of years traveling around the universe isn't necessarily a "one way trip".
smcllns 8y ago
Several threads here mention the problem with sample size of one. That's true that it makes it very hard. But there's some interesting extra information we can also extract from this one sample: Life on earth either 1) developed naturally from physics or 2) arrived here from another place. If #1, it means life will develop in other places in the universe - and can do to the extent of transmitting electromagnetic waves. If #2, it already exists/existed elsewhere and was clever enough to send itself elsewhere and evolve to send electromagnetic waves. From all the life that has evolved on earth, from bacteria to trees (to clever octopus) to humans, a very small percentage of that life evolved to create a signal that is detectable far away (humans/radio waves). I don't really know how to factor this into the paradox, but based on the above, it seems so possible to me that life widely exists but it is simply a miniscule % that has evolved in such a way to use electromagnetic energy in a way that is detectable by us today.
matte_black 8y ago
What if life is actively being destroyed by some powerful civilization? For us life may be some beautiful miracle worth cherishing but perhaps there’s a brutal species out there with no greater regard for it than the weeds growing in our gardens. On an intergalactic timescale humanity has only been around for the blink of an eye. So probably not long enough for a civilization that operates on cosmic scale heartbeats to have noticed us yet. When they do though, they might cast off a gamma ray burst in our direction and sentence us to death, checking back to see the carnage several lightyears later, just like they have done with so many other planets teeming with life. They have made a critical error though: they are entirely too late. They should have done it when we were little more advanced than the beasts who graze on the grasslands. We are now on the brink of exponential technological advancement. By the time they fire off their attack we’ll see them coming and have time to prepare. They will have given away their position, and by the time they look for the dust of what was once our home they will find a hundred new starships and space stations, expanding rapidly away but a great portion moving closer in an ominous pattern. Then they will realize what they have done. This time, they messed with the wrong species. And then our message will arrive. As they look at each other right to left and left to right with some alien expression of panic, a malevolent vibration will carry the voice of humanity unified in a way that it has never been before. This will not be the peaceful, optimistic greeting of our Voyager. This will be something unmistakable in it’s intent, something that can only be promised by a civilization that’s been killing itself and nearly killing it’s own planet for all it’s existence, and now thirsting for revenge with a rage handed down from generation to generation. Whenever these beings sleep, if they must sleep, they will be haunted with echoes of our message, still ringing in their heads loud and clear: "We’re coming for you—motherfuckers."
Falkon1313 8y ago
The real problem is that it's built on a foundation of assumptions, all of which are completely anthropocentric - more specifically, that foundation's cornerstone is based upon the behavior of humans in developed countries during the 20th century. Especially repressed aggression. It really tells us a lot more about ourselves than about aliens. "If aliens exist, they would send tight-beam radio communications on this exact frequency (because that's the one that we'd choose!), in a format that we could recognize as an attempt to communicate (probably English, because we all speak English! Or maybe Morse code), and keep spending resources doing it for however many thousands or millions of years it took for us to notice." Even we don't even do that. Most of our radio transmissions now are short-range bluetooth, wifi, cellular, or satellites pointed at the planet. Our broadcast signals, though some might be strong, are attenuating in cubic space and all mixed together containing all channels and stations - white noise and static at best. We just assume that if they're not speaking our language in our formats, they're not really civilized/advanced. "If aliens exist, they would have conquered the entire galaxy by now, because that's what we'd do!" I've lived here for years and haven't tried to conquer my neighbors and have no intention of doing so. Yet we assume any sufficiently-advanced aliens must be violent. "If we couldn't conquer it straight away, we'd at least send self-replicating robots to claim every planet! So if aliens existed, of course they would have done that!" They may not be self-replicating, but any of us could buy drones and send them to claim undeveloped plots of land that we couldn't use. Yet we don't. It'd be pointless. But we assume any sufficiently-advanced aliens must be selfish. "We've been ripping every resource out of the planet as fast as we can and polluting as much as possible to maximize profits and shareholder value. If aliens exist, they would do the same and even go as far as creating Dyson spheres!" Well yes, we do destroy our environment. But some of us have realized that it is a bad idea to do that and we should probably ramp it down, rather than go to the full extreme of destroying our entire solar system. Yet we assume any sufficiently-advanced aliens must be greedy. I don't really think it's a paradox mainly because I don't have that underlying assumption that all aliens must act like the noisiest, greediest, most violent and self-absorbed humans of the 20th century. Perhaps the paradox is that we expect all civilized life in the rest of the universe to be as bad as the worst of us, and it's just not, and we don't have an explanation for that yet.
yedawg 8y ago
We are here, so why can't aliens exist, right? I don't think it's as simple as the drake equation suggests. There are trillions of variables that life on earth has had to overcome with relative success. Even this is abstract and is in turn subjective. I speculate that if we repeatedly redefine our assumptions on how unlikely it is for life to arise in our part of the universe, we still only have a potential baseline for life in the milky way; this is again skewed by our position in the solar system and cannot be reasonably accounted for by an algorithm. (We don't know what we can't test)
gmuslera 8y ago
The Fermi Paradox makes me remind of https://xkcd.com/605/ https://xkcd.com/605/ . Would that extrapolation look normal for an alien or for someone of a radically different culture? Oh, even a child from our culture would argue that you just can't marry twice not each day, but for total outsiders it won't be so obvious and even some may think that it should happen. We are outsider ones in this Fermi Paradox extrapolation. We are very far from being able to do interstellar travel, specially in scale, tripulated, or thinking in some way of colonization, even for our closest star system. Like with the weddings, we are extrapolating without knowing anything about how it is really in practice interstellar travel and colonization, specially in big scale. And more than just about physics, it assumes more things about intra/inter alien culture. They must expand as much as they can, and they must do visible for everyone things (dark forest? nah), and interstellar travel/colonization is possible and desirable... those, besides the Drake equation, are the axioms of it. And they may not be true or at least give another big factor to consider in the Drake equation. Not knowing is not equal to knowing that not. You must leave space for things that you don't know that you don't know.
framitz 8y ago
Does the Drake equation model the universe to provide any real insight into the Fermi Paradox? Even if it does, only a few factors have enough data points to allow the ranges in the learned SDO analysis to strongly illuminate the question, “Where’s ET?” We slowly make empirical progress on the ranges. For one thing, we now know how many stars in the immediate neighborhood have planets: the vast majority. We now know that the prospects for water/organic based “life” look pretty good in our neighborhood: there are in the range of half a dozen prospects in our solar system. We might nail that one down a bit more within a few decades. We just need one hit on Enceladus, Europa, or Mars. Until contact is confirmed, it seems the question comes down to two big problems: (1) It took 3-4 billion years for life on earth to evolve from first replicating molecules to “intelligent life.” Our species is ≈ 200,000 years old. That represents 1/23000th the age of the earth. (2) We have had “radio” (radiotelegraphy) for a little more than one century. That represents 1/46 millionth the life of the planet. Assuming humans survive for quite a while longer, what are the chances that another species—say, within 1000 light years of us—will be using “radio” (EM communication) at the same time? Even if our two species each survive a million years, the chances we appear at the same time are slim. A million years represents 1/4600th the life of our planet. On a positive note, there are in the range of 16 million stars within 1000 light years of earth. The Fermi Paradox presumes much: intelligent life is destined to evolve on suitable planets; intelligent life survives the filters (my doomsday money is on human pollution, ye olde shite problem); EM communication or star travel is a logical outcome of intelligent life. All of these seem a bit dubious to my limited mind. On the other hand, almost by definition, a starship is immortal. If humans ever achieve a viable industrial infrastructure, at say, Jupiter, we will have already overcome many of the obstacles of traveling to Alpha Centuri. A self-contained, self-repairing, self-propulsing “vehicle” has to avoid collision, of course. Here, my money bets first contact will be, or has been with machines.

189 points by laurex 8y ago

> If this is right – and we can debate exact parameter values forever, but it’s hard to argue with their point-estimate-vs-distribution-logic – then there’s no Fermi Paradox. It’s done, solved, kaput. this makes no sense at all: whether or not there is a fermi paradox absolutely depends on the parameters "we can argue about"

OscarCunningham 8y ago
Perhaps it be accurate to say the given our current knowledge about the parameters there's not currently a Fermi paradox, but if we gained more information about the parameters then a Fermi paradox could arise in the future.
- rad88 8y ago
  But nothing at all is really known about "length of time for which such civilizations release detectable signals into space". It's somewhere between a few decades or so and 10 billion years?
  - OscarCunningham 8y ago
    Sure, which is one of the reasons why we don't currently have a Fermi paradox.
    - EthanHeilman 8y ago
      To me the Fermi Paradox isn't really a paradox it is framework for thinking about the problem. This research fits into that framework and provides an interesting new argument that the great filter is more likely to be in our past rather than our future.
  - bena 8y ago
    IIRC, we're already going dark. The amount of "noise" we broadcast into space is diminishing. If other civilizations roughly follow the progress of our own, that could mean that the window a civilization has to be detected is something like 100 - 200 years.
- jandrese 8y ago
  It all comes down to trying to draw a line from a single point. We don't have enough information to even make an educated guess at this point. IMHO the Fermi paradox has one flawed assumption: that interstellar travel for the purposes of colonization would be possible and desirable. If this is not the case then there is no paradox, everybody is in their solar system happily doing whatever it is they do all day.
  - bena 8y ago
    Exactly. To transfer something between Earth and the nearest star would require about 8 years. Fuck having a pen pal. You'd also need the energy to propel something to the speed of light. Is it even worth it?
    - neaden 8y ago
      I would think so, for an advanced enough civilization certainly you could expect to see something like Bracewell probes getting sent out to go say hi without spending too many resources.
      - Retric 8y ago
        Sending 1 probe might be low resources. Try sending 1 probe to every star ever 10,000 years. Because without that the odds of any probe being near us is rather limited. As to self replicating probes that's freaking dangerous. Get something wrong and the universe becomes a very hostile place. PS: In terms of cost consider the % of humanity's GDP spent on SETI projects. Now consider those at least have the possibility of some benefit in your lifetime. Extra Solar probes are unlikely to get much in the way of resource investment from most civilizations.
      - bena 8y ago
        He said "for the purposes of colonization". That means sending people out. We would be sending people on one-way trips, for better or worse. You'd likely never hear from them again. As to just sending out Bracewells to say "Hi", why? Once again, the return on a response is very long and not guaranteed. And without a response, what's the point?

pfortuny 8y ago

Wilmott has a simpler way of explaining it: in a magician’s show, what are the odds that he guesses your card right? The question makes no sense because there is no plausible model: he may willingly decide to guess wrong, for example, or the trick may consist in making you forget the card or any other thing. Assigning probabilities without a real model is just hubris, no more.

zentiggr 8y ago
But it is human nature to speculate, to have an opinion no matter how unfounded. Personally, I think the chance of encountering another civilization is exactly [0,1]. Pending data to adjust that range.
whatshisface 8y ago
You could go to ten thousand magic shows and write down the result of the card guessing each time. Then, based on those probabilities, you could win on average a betting game between audience members about the results of future tricks. No model required.

ravenstine 8y ago

You can calculate all the probabilities you want all day and night, but there's still no evidence. Until we have a frequency of how often life occurs, rather than a single occurrence, speculated probability doesn't mean anything. Especially when we can't even create life in a lab. (If I remember correctly, we've been able to create amino acids using early-Earth conditions, but we haven't really been able to create something like RNA.) The Fermi Paradox hasn't been "dissolved" in any way. It's a response to the idea that the universe is teaming with life. The paradox remains unchanged until we find a credible signal, or we create life in a lab under naturalistic conditions.

AnimalMuppet 8y ago
Even if we create life in a lab under naturalistic conditions, that doesn't answer the question. How often do those conditions occur on planets in the universe? We need an actual number. How often does life arise given those conditions? We need an actual number for that, too.
- deleted 8y ago
  [deleted]
- a_t48 8y ago
  Also, what if there are other conditions life can start under?
  - AnimalMuppet 8y ago
    And what are they? And how probable are those conditions? And how often does life start under those conditions?
    - TeMPOraL 8y ago
      And what is life? Does it have to be DNA-based replicators? Just carbon-based? Matter-based?
8y ago

s-shellfish 8y ago

The Fermi Paradox, to me, is more a philosophical question about the destructive nature of humanity, than it is actually talking about alien civilization. Points of note are 'what is the bottleneck to traveling outside of the space we inhabit?'. Why does one ask the question 'why don't we see life everywhere?'. Lately, some of the time I see this as a metaphor for 'what is the dilemma with broadening horizons?' There could be alien life, there could not be. It's interesting to think about for a while but sometimes I think it is talking about something deeper than the existence of aliens and outer space. Philosophical question about the nature of existence.

thaumaturgy 8y ago

The actual paper, linked from the top of this article, is very readable and I'd recommend taking the time for it. In summary, the traditional approach to the Drake Equation has been to assign fixed values to each polynomial, sometimes an ass-pull and sometimes based off of best estimates from the observable universe. i.e., "0.1 x 0.1 x 0.1 x 0.1..." What these researchers did instead is try to account for the uncertainty of various parameters. They gave each polynomial values in the range of [0, 0.2] for example, ran Monte Carlo simulations on that, and came up with an empty universe 21.45% of the time. To put it another way: we consider it a certainty that some worlds will bear life, and a certainty that some of that life will develop into intelligent civilizations, and a certainty that some of those intelligent civilizations will explore their local system, and a certainty that some of those explorers will develop into massive hyper-intelligent, technologically-advanced, galaxy-spanning species. But we haven't got enough information to be certain about any of those within any reasonable order of magnitude. The probability of any one of those may in fact lie so close to 0 that it solves the Fermi Paradox. FWIW (and it's worth basically nothing), this has been my preferred solution to the Fermi Paradox for a long time now, and it's nice to have this paper to cite when it comes up in the future. I figured that it took Earth 4.5 billion years to produce humans, and humans are only barely space-faring at this point and I'm not certain we'll ever make it out of our solar system. Countless species have appeared and gone extinct in the meantime. It seems far from certain, to me, that evolution necessarily leads to intelligent life, and if I remember right, the latest thinking from evolutionary biologists supports this -- suggesting that modern human intelligence is largely accidental, rather than a byproduct of evolution. The age of the universe would seem to suggest that there's been time for at least a few other worlds to develop intelligent life even at very slow, unlucky paces, but then again, at astronomical time scales the universe has been too violent up until recently to foster that kind of development. The Fermi Paradox seems to have captured a lot of interest from people who like sci-fi and want to think about all kinds of fantastic ideas on why we appear to be alone. Is there a Great Filter? Is this a simulation? Are we in some kind of super-advanced stellar nursery? It's like nerd sniping (https://www.xkcd.com/356/ https://www.xkcd.com/356/) for a particular sort of nerd.

jerf 8y ago
I have no idea why, as I write this, the parent is greying out. It's the only reasonable comment on the article as I write this. I know you're really not supposed to tell people they need to read the article on HN, but the paper underlying the article may be the least understood primary source I've ever seen posted to Hacker News. (This beats out the previous record holder, monad tutorials based around an actively incorrect metaphor.) This is not just a standard reiteration of the Fermi Paradox with somebody's new numbers pulled out of the air. It is a legitimately interesting analysis of the problem as a whole. Read the article and/or the underlying paper, carefully, before just reciting the Standard Cant Against the Fermi Paradox, OK? (And downvoting the only person giving a decent explanation of it.) The Standard Cant is encompassed and superseded by the paper in question, with mathematics.

madeuptempacct 8y ago

As of today, we wouldn't be able to detect a same-tech-level civilization even at the closest star with the amount of effort we have given this, so there is no paradox in my mind.

joe_the_user 8y ago
Agreed, strongly. The Fermi problem is a speculative theory based on extrapolating human civilization's use of energy to stellar levels (various hypothetical civilization "types" etc). It's plausible life at the scale of earth could be common, based on the principle of our natural non-uniqueness. So the simplest explanation is the speculative extrapolation to stellar energy uses is wrong - human already are more destroying themselves with excess energy use than preparing for any next stage, just as one datum.
roywiggins 8y ago
All it takes is one sufficiently early civilization that goes full Neumann-replicator and decides to colonize every system it can for them to have already arrived here long ago. The fact remains that it seems like they didn't, unless they were very careful boy scouts and left no trace.
- nv-vn 8y ago
  There are so many variables. For example, if they can't travel faster than the speed of light, they might not even think it's worth colonizing. They could also be on scales vastly different from our own, as microbes or as planets. We wouldn't even know what to look for in interstellar communications, let alone have the ability to make sense of anything they send. Our entire "search" has come with the assumption that alien life is going to communicate with radio waves, use sight (in the same range as our own), be similar in size to us, etc.
  - roywiggins 8y ago
    It just takes one weirdo civilization that decides to put up Ozymandias-style monuments to themselves everywhere- they don't even need to do it themselves. They can fire off a few Von Neumann probes and let them do the work to carve Mount Rushmores into every rocky body they can find. It's not much weirder than things humans get up to, and if spacefaring civilizations that can build such probes are common at all (even if short-lived), you might expect at least one of them to have initiated such a project and been successful enough to have built a giant "we wuz here" radioactive pyramid on the moon. Evidently, none of them did- and depending on how many there were, this is either unsurprising or deeply unlikely.

neals 8y ago

So, my fellow HN dreamers... Would you rather be the first or the last civilization in existence?

lainga 8y ago
First, so I can show up in the 3rd or 4th installment of a future civilization's video game franchise as an "Ancient One" and speak in hexameter.
- vkhorikov 8y ago
  Also first so I can introduce a Reaper and make sure no other civilization can advance too much
TeMPOraL 8y ago
The middle one. So that we have plenty of younger civilizations to teach and kick around the block if they misbehave. But also so that we have some Ancient Ruins to discover and learn about Meaning of Life from, triggering all the good feels I usually get at this point when watching sci-fi shows.
squirrelicus 8y ago
I believe aliens have no reason to not genocide us immediately upon discovering us, so I'd rather be the only civilization. But to answer your question, absolutely the first. That way, if we are more benevolent than the Machiavellian necessity, we will either pioneer an improbable United Federation of Planets or be eradicated due to our idealism and naivete.

jasonkolb 8y ago

I've been listening to the "3 Body Problem" trilogy by Cixin Liu. I'd highly recommend it because not only is it some mind blowing sci-fi, but it also contains one of the most interesting solutions to the Fermi paradox that I've ever seen. I don't want to give anything away because the books are a real treat if you're like me, but the explanation is based on game theory and actually makes a ton of sense. Highly recommended.

garmaine 8y ago
Try the Revelation Space series for a better, and earlier take on the idea. The 3 body problem is masquerading as hard SF but isn’t. The author totally misunderstands physics, astronomy, and space faring technology. I hated the books, personally, and don’t see why they are so hyped.

jhallenworld 8y ago

I find the argument that advanced growing alien civilizations would construct "Dyson Swarms" pretty convincing. These structures have the huge advantage that no new physics is required- we could start building ours now with today's technology. They would look like infrared point sources. Sadly none detected yet: https://medium.com/starts-with-a-bang/dyson-spheres-the-ultimate-alien-megastructures-are-missing-from-the-galaxy-447f5f87c2dc https://medium.com/starts-with-a-bang/dyson-spheres-the-ulti...

canhascodez 8y ago
The SNR to Mars is not great at the best of times. We no longer radiate a great deal of high-power analog signals, because those are not efficient. Space is noisy, digital signals look very much like noise, and radiating to space is not usually the most efficient thing to do if you can avoid it. Our chances of detecting our own planet even from the nearest star would be pretty minimal. Perhaps someone might be able to explain to me why we postulate being able to detect extrasolar aliens.
- Chris_Chambers 8y ago
  A Dyson swarm essentially attempts to completely surround a star with solar panels. Infrared wavelengths would then be uncontrollably radiated out into space by the overheating solar panels.
  - canhascodez 8y ago
    Yes, I'm aware. How many of those do you think you could hide in a ten-light-year circle around Earth, and how long do you think it would be before we were able to find them? To a first approximation, the only things that we can see at stellar scales are stars, and all of the discussions on this topic seem to revolve around detecting radio transmissions. This page[0] gives pretty pessimistic numbers for the maximum SNR to Mars. There seems to be some massive disconnect between what people are looking for and what we are currently emitting, or what we might expect an advanced species to be emitting. And my assumption in these cases is that it's substantially more likely that I am a fool and missing something important rather than that everyone else is. [0] http://www.astrosurf.com/luxorion/qsl-mars-communication3.htm http://www.astrosurf.com/luxorion/qsl-mars-communication3.ht...

thomk 8y ago

I know everything I know about the Fermi Paradox from this video (and part 2): https://www.youtube.com/watch?v=sNhhvQGsMEc https://www.youtube.com/watch?v=sNhhvQGsMEc That YouTube channel is awesome by the way. Say goodbye to the rest of your afternoon!

microtherion 8y ago

Previous discussions here: https://news.ycombinator.com/item?id=14686687 https://news.ycombinator.com/item?id=14686687 And here: https://news.ycombinator.com/item?id=17302924 https://news.ycombinator.com/item?id=17302924

based2 8y ago

https://en.wikipedia.org/wiki/Gamma-ray_burst https://en.wikipedia.org/wiki/Gamma-ray_burst

tjradcliffe 8y ago

"Maybe people intuitively figured out what was up (one of the parameters of the Drake Equation must be much lower than our estimate) but stopped there and didn’t bother explaining the formal probability argument." There's no "intuitively" about it. We know from the data available that the probability of machine-building general intelligence of the kind that is unique to humans on Earth is fantastically unlikely to arise. It depends on a confluence of completely unrelated selective pressures: one on tool-making, one on social cooperation, and one on continuous mate competition/selection. There is good evidence that all of those forces are important to specifically human--not dolphin or bird or whatever--intelligence on Earth, and without any one of them we'd still be fairly handy monkey-creatures banging rocks around. As well as a theoretical understanding, we have empirical data. We can ask, "If something is at all probable how many times will it have evolved on Earth?" Eyes, for example, have evolved independently multiple times, based on differences in retinal biochemistry. Wings and fins and legs have also evolved many times across an incredible diversity of species. This tells us that things that are easy to evolve have evolved multiple times in Earth's history. Specifically human, machine-building intelligence has evolved exactly once. This is strong evidence that it has an enormously low probability. Once you've realized that one of the parameters in the Drake equation is incredibly small, the Silent Universe is no longer surprising. And both empirically and theoretically, the probability of evolving specifically human, machine-building intelligence is incredibly small. However, I have never met anyone enamoured of Fermi's Paradox who gives any credence to this, which is why no attempt to resolve the paradox will ever have any effect on the discussion. This is in general the case with so-called paradoxes: no matter how many times they are clearly and simply resolved, people who want there to be paradoxes will pretend the resolution doesn't exist, or will deliberately misrepresent it as a non-solution. Or they will present some other non-solution as more compelling, even when the solution presented makes those non-solutions unnecessary.

rossdavidh 8y ago

This whole idea of "dissolving" the Fermi paradox seems to be missing the point. Everyone knows that we have, in fact, not observed an alien civilization, so one of the factors in the Drake equation (or one we should have put in) is responsible. But, is it that there is very little chance of life evolving, or intelligence? Or is it that intelligence tends to be short lived? Or is it because long-lived intelligence uses methods of communication we cannot observe, and is responsible enough not to colonize all the good planets? The consequences for us are large, depending on which one of those it is. Merely saying "well it's not that surprising that one of those factors is tiny" is not really relevant to the question of, which factor is it that is tiny?

thaumaturgy 8y ago
This is addressed in the paper. They estimate that the greatest uncertainties lie in the past terms of the Drake Equation, ergo that there is no evidence of some great threat to the continued advancement of human civilization.
- bryanrasmussen 8y ago
  Here would seem to be the limit of Bayesian analytics bridging the causal gap.
danShumway 8y ago
No, what the article is saying is that when you rely on distributions of outcomes from the Drake equation rather than averages, it's much more likely that you'll get tiny results. You don't need extremely low values in the Drake equation to end up with nearly no aliens. It's actually kind of likely that we're (close to) alone, even without a crazy complicated theory to justify one of the values being nearly zero. This is missing the point that many people do treat the Fermi Paradox like it's a real paradox - like there's some kind of fundamental universal principle that has to almost universally block out all life or all communication. The article is saying you don't need it. It's good enough to say "well, life might just be sort of uncommon, and even in that scenario we shouldn't be surprised that we got a very low roll." That is a surprising conclusion. No, we don't know the exact cause, but it means that the Fermi Paradox might not be a paradox, in the sense that it doesn't directly contradict all of our priors. Think of it like the difference between saying, "Trump won the election because we fundamentally don't understand how democracy works in practice", and "Trump won the election because he had a 1 and 5 chance of winning, and sometimes 20% chance events happen."

sebringj 8y ago

The laws of physics are not localized to earth and yet we see life on earth among countless other possible earths with extreme immense distances between them that light (communication) takes thousands if not millions of years to reach. We see life evolving in the heat vents at the bottom of the ocean along with entirely different paths of evolution to create an eye. Why is this a mystery we have not seen intelligent life? Earths may be frequent and life as well but intelligent life capable of communicating through light AND close enough to communicate may be very very rare. After all, we are only here because the dominant dinosaurs with tiny brains died out changing the rules. In other words, I don't know but intelligent life isn't necessarily the normal end game.

Klathmon 8y ago
But part of the paradox is that "universe time" is so monumentally longer than "human time". Even if only a fraction of a fraction of a fraction of all life make it to what we could call "intelligence", then those beings are most likely millions or billions of years "ahead" of us, or won't be intelligent for millions or billions of years from now. At those timescales, even things millions of light-years away are "within reach" of some kind of contact, unless there is something making it impossible (like all intelligent life snuffs itself out given enough time). This is easily one of my favorite things to just think about.
- gowld 8y ago
  you don't need to "snuff out" life to make it undetectable to us, you just need something that prevents life from getting complex enough for interstellar travel. It's quite plausible that live ebbs and flows (like it has on Earth), but never gets large enough and powerful enough to be detected at remote locations subject to inverse-square signal dissipation.
- sebringj 8y ago
  I think that's a pretty good point. The vastness of space should be changed to the vastness of space-time which then makes it feel even less likely to find intelligent life which is a little sad.

ared38 8y ago

> Why didn’t anyone think of this before? Anyone that's read even the intro section of the Fermi paradox Wikipedia page already has: "There have been many attempts to explain the Fermi paradox ... suggesting that intelligent extraterrestrial life is extremely rare". The paper just formalizes that by demonstrating we can arrive at low enough expected numbers of aliens (namely 0) with reasonable inputs to the drake equation. > Imagine we knew God flipped a coin. If it came up heads, He made 10 billion alien civilization. If it came up tails, He made none besides Earth. This occludes a lot more than it illuminates. Although the end section of the paper uses the bayesian inference Sniffnoy hinted at, the graphs SSC used (and his analysis of the papers results) come from the earlier section of the paper that still use the "chance of aliens per star" model. Even the bayesian part merely refines this probability based on observations; it's hardly "the wrong way to think about it" as SSC claims.

lisper 8y ago

TL;DR: expected values can be very improbable. The expected value of a Powerball ticket is >0, and in fact by increasing the amount of the prize the expected value can be made arbitrarily large. But the probability that the actual value will be >0 is very nearly zero. And most importantly: that probability does not change as the prize money (and hence the expected value) increases. No matter how big the prize is, you will nonetheless almost certainly not win.

wilg 8y ago

Question for someone smarter than me: is this a similar argument to this[1] 1985 paper (referenced by Wikipedia in the "criticism of logical basis" section[2] on the Fermi Paradox article)? [1] http://adsabs.harvard.edu/abs/1985Icar...62..518F http://adsabs.harvard.edu/abs/1985Icar...62..518F [2] https://en.wikipedia.org/wiki/Fermi_paradox#Criticism_of_logical_basis https://en.wikipedia.org/wiki/Fermi_paradox#Criticism_of_log...

vlasev 8y ago
No. This 1985 paper you reference talks about a logical argument for why there is no paradox, whereas the discussed paper is talking about how the uncertainty in the parameters is enough to yield something that is not a paradox.

DaveInTucson 8y ago

For me, the problem with the Fermi paradox is that we only have one poorly understood and incompletely documented example of a planet with intelligent life from which to draw conclusions. Beyond that: * How many habitable planets are out there? We're just now starting to get data on this, there might be a lot * Of those, how many develop life? * Of those that develop life, how many develop intelligent life? * Of those that develop intelligent life, how many advance to the point where they're capable of interstellar travel? How many are interested in interstellar travel? * What if FTL travel is simply not possible? STL interstellar travel could basically be a one-way trip. Maybe most (or all) alien civilizations are unwilling to explore beyond a few light years. * What is the lifetime of a space faring civilization? maybe all the alien civilizations just died out before they explored very far.

Klathmon 8y ago
Widen your idea of life. What if another species has figured out a way around death? What if the idea of a single "life" isn't really a thing, and alien lifeforms instead live as a single "consciousness" among them all forever alive. Then the idea of spending millions or billions of years traveling around the universe isn't necessarily a "one way trip".

smcllns 8y ago

Several threads here mention the problem with sample size of one. That's true that it makes it very hard. But there's some interesting extra information we can also extract from this one sample: Life on earth either 1) developed naturally from physics or 2) arrived here from another place. If #1, it means life will develop in other places in the universe - and can do to the extent of transmitting electromagnetic waves. If #2, it already exists/existed elsewhere and was clever enough to send itself elsewhere and evolve to send electromagnetic waves. From all the life that has evolved on earth, from bacteria to trees (to clever octopus) to humans, a very small percentage of that life evolved to create a signal that is detectable far away (humans/radio waves). I don't really know how to factor this into the paradox, but based on the above, it seems so possible to me that life widely exists but it is simply a miniscule % that has evolved in such a way to use electromagnetic energy in a way that is detectable by us today.

matte_black 8y ago

What if life is actively being destroyed by some powerful civilization? For us life may be some beautiful miracle worth cherishing but perhaps there’s a brutal species out there with no greater regard for it than the weeds growing in our gardens. On an intergalactic timescale humanity has only been around for the blink of an eye. So probably not long enough for a civilization that operates on cosmic scale heartbeats to have noticed us yet. When they do though, they might cast off a gamma ray burst in our direction and sentence us to death, checking back to see the carnage several lightyears later, just like they have done with so many other planets teeming with life. They have made a critical error though: they are entirely too late. They should have done it when we were little more advanced than the beasts who graze on the grasslands. We are now on the brink of exponential technological advancement. By the time they fire off their attack we’ll see them coming and have time to prepare. They will have given away their position, and by the time they look for the dust of what was once our home they will find a hundred new starships and space stations, expanding rapidly away but a great portion moving closer in an ominous pattern. Then they will realize what they have done. This time, they messed with the wrong species. And then our message will arrive. As they look at each other right to left and left to right with some alien expression of panic, a malevolent vibration will carry the voice of humanity unified in a way that it has never been before. This will not be the peaceful, optimistic greeting of our Voyager. This will be something unmistakable in it’s intent, something that can only be promised by a civilization that’s been killing itself and nearly killing it’s own planet for all it’s existence, and now thirsting for revenge with a rage handed down from generation to generation. Whenever these beings sleep, if they must sleep, they will be haunted with echoes of our message, still ringing in their heads loud and clear: "We’re coming for you—motherfuckers."

Falkon1313 8y ago

The real problem is that it's built on a foundation of assumptions, all of which are completely anthropocentric - more specifically, that foundation's cornerstone is based upon the behavior of humans in developed countries during the 20th century. Especially repressed aggression. It really tells us a lot more about ourselves than about aliens. "If aliens exist, they would send tight-beam radio communications on this exact frequency (because that's the one that we'd choose!), in a format that we could recognize as an attempt to communicate (probably English, because we all speak English! Or maybe Morse code), and keep spending resources doing it for however many thousands or millions of years it took for us to notice." Even we don't even do that. Most of our radio transmissions now are short-range bluetooth, wifi, cellular, or satellites pointed at the planet. Our broadcast signals, though some might be strong, are attenuating in cubic space and all mixed together containing all channels and stations - white noise and static at best. We just assume that if they're not speaking our language in our formats, they're not really civilized/advanced. "If aliens exist, they would have conquered the entire galaxy by now, because that's what we'd do!" I've lived here for years and haven't tried to conquer my neighbors and have no intention of doing so. Yet we assume any sufficiently-advanced aliens must be violent. "If we couldn't conquer it straight away, we'd at least send self-replicating robots to claim every planet! So if aliens existed, of course they would have done that!" They may not be self-replicating, but any of us could buy drones and send them to claim undeveloped plots of land that we couldn't use. Yet we don't. It'd be pointless. But we assume any sufficiently-advanced aliens must be selfish. "We've been ripping every resource out of the planet as fast as we can and polluting as much as possible to maximize profits and shareholder value. If aliens exist, they would do the same and even go as far as creating Dyson spheres!" Well yes, we do destroy our environment. But some of us have realized that it is a bad idea to do that and we should probably ramp it down, rather than go to the full extreme of destroying our entire solar system. Yet we assume any sufficiently-advanced aliens must be greedy. I don't really think it's a paradox mainly because I don't have that underlying assumption that all aliens must act like the noisiest, greediest, most violent and self-absorbed humans of the 20th century. Perhaps the paradox is that we expect all civilized life in the rest of the universe to be as bad as the worst of us, and it's just not, and we don't have an explanation for that yet.

yedawg 8y ago

We are here, so why can't aliens exist, right? I don't think it's as simple as the drake equation suggests. There are trillions of variables that life on earth has had to overcome with relative success. Even this is abstract and is in turn subjective. I speculate that if we repeatedly redefine our assumptions on how unlikely it is for life to arise in our part of the universe, we still only have a potential baseline for life in the milky way; this is again skewed by our position in the solar system and cannot be reasonably accounted for by an algorithm. (We don't know what we can't test)

gmuslera 8y ago

The Fermi Paradox makes me remind of https://xkcd.com/605/ https://xkcd.com/605/ . Would that extrapolation look normal for an alien or for someone of a radically different culture? Oh, even a child from our culture would argue that you just can't marry twice not each day, but for total outsiders it won't be so obvious and even some may think that it should happen. We are outsider ones in this Fermi Paradox extrapolation. We are very far from being able to do interstellar travel, specially in scale, tripulated, or thinking in some way of colonization, even for our closest star system. Like with the weddings, we are extrapolating without knowing anything about how it is really in practice interstellar travel and colonization, specially in big scale. And more than just about physics, it assumes more things about intra/inter alien culture. They must expand as much as they can, and they must do visible for everyone things (dark forest? nah), and interstellar travel/colonization is possible and desirable... those, besides the Drake equation, are the axioms of it. And they may not be true or at least give another big factor to consider in the Drake equation. Not knowing is not equal to knowing that not. You must leave space for things that you don't know that you don't know.

framitz 8y ago

Does the Drake equation model the universe to provide any real insight into the Fermi Paradox? Even if it does, only a few factors have enough data points to allow the ranges in the learned SDO analysis to strongly illuminate the question, “Where’s ET?” We slowly make empirical progress on the ranges. For one thing, we now know how many stars in the immediate neighborhood have planets: the vast majority. We now know that the prospects for water/organic based “life” look pretty good in our neighborhood: there are in the range of half a dozen prospects in our solar system. We might nail that one down a bit more within a few decades. We just need one hit on Enceladus, Europa, or Mars. Until contact is confirmed, it seems the question comes down to two big problems: (1) It took 3-4 billion years for life on earth to evolve from first replicating molecules to “intelligent life.” Our species is ≈ 200,000 years old. That represents 1/23000th the age of the earth. (2) We have had “radio” (radiotelegraphy) for a little more than one century. That represents 1/46 millionth the life of the planet. Assuming humans survive for quite a while longer, what are the chances that another species—say, within 1000 light years of us—will be using “radio” (EM communication) at the same time? Even if our two species each survive a million years, the chances we appear at the same time are slim. A million years represents 1/4600th the life of our planet. On a positive note, there are in the range of 16 million stars within 1000 light years of earth. The Fermi Paradox presumes much: intelligent life is destined to evolve on suitable planets; intelligent life survives the filters (my doomsday money is on human pollution, ye olde shite problem); EM communication or star travel is a logical outcome of intelligent life. All of these seem a bit dubious to my limited mind. On the other hand, almost by definition, a starship is immortal. If humans ever achieve a viable industrial infrastructure, at say, Jupiter, we will have already overcome many of the obstacles of traveling to Alpha Centuri. A self-contained, self-repairing, self-propulsing “vehicle” has to avoid collision, of course. Here, my money bets first contact will be, or has been with machines.