9 ms·

Once we can see them, it’s too late

145 points by gadtfly 6y ago

newsbinator 6y ago
Even if we do have young competitors like us, they could still be millions of years older than us- the blink of an eye, in a planet’s lifecycle. But millions of years of technological evolution is plenty enough time to make grey goo (or light speed spheres of incoming civilization).
dfabulich 6y ago
The site appears to be down. (504 Gateway Timeout) https://archive.is/ki5Vm https://archive.is/ki5Vm
isoprophlex 6y ago
This is the most profound thing I've read in a while. I'm tempted to whip up some numerical simulation to verify this to some extent... > But here’s the interesting part: conditioned on all the steps having succeeded, we should find ourselves near the end of the useful lifetime of our planet’s star—simply because the more time is available on a given planet, the better the odds there. I.e., look around the universe and you should find that, on most of the planets where evolution achieves all the steps, it nearly runs out the planet’s clock in doing so.
- Gupie 6y ago
  But we had a billion years left. We have plenty of time to do whether we are going to do before the "planets clock runs out".
  - nojokes 6y ago
    and we just getting started.
- bpodgursky 6y ago
  Robin has done a fair bit of numerical simulation on his OP posts here https://www.overcomingbias.com/2020/12/how-far-aggressive-aliens-part-2.html/ https://www.overcomingbias.com/2020/12/how-far-aggressive-al..., and says he'll have an actual paper out in a week or two.
  - isoprophlex 6y ago
    Thanks! Looking forward to reading the paper..!
- btilly 6y ago
  Want something scary? The form of reasoning used is exactly that in the https://en.wikipedia.org/wiki/Doomsday_argument https://en.wikipedia.org/wiki/Doomsday_argument for why humanity is unlikely to last long, and almost certainly will not have a future where we break out and colonize most of the Solar System, let alone the stars. If you believe both arguments, the most likely outcome is that there is one more step on the way to Robin's argument. And that outcome is the replacement of biological intelligence with mechanical. So indeed we give rise to an expanding wave of technological civilization. But we are close to peak population and will not ourselves see that civilization. All hail our future AI overlords!
  - bob33212 6y ago
    We are within 500 years of creating millions of self sustaining spaceports. We are within 500 years of AGI. We are within 500 years of understanding quantum gravity. We are within 500 years of fixing biological death. The order we get to those and how they interplay and change the world matters so much that it doesn't make sense to worry about making predictions.
    - AnimalMuppet 6y ago
      You state these "we are within 500 years" as if they are certainties, but you show no evidence for any of them. The only one I consider even slightly likely is that we are within 500 years of understanding quantum gravity. So... evidence? Argument? Just stating baldly that it is so is not very convincing.
      - bob33212 6y ago
        I don't have a time machine so no I cannot prove what will happen in the future
        AnimalMuppet 6y ago
        Fine, but you seem to regard it as at least virtually certain. Why? What is your basis for regarding it as close to certain?
chmod600 6y ago
Even in case #3, is it reasonable to assume that the aliens would expand in 3 dimensions at the speed of light? And even of that is true, wouldn't we expect a significant fuzziness in that on the order of a millenium, where we see signs but haven't yet been engulfed?
- Gupie 6y ago
  But if a civilization has been expanding for a billon years the chances very small that you are this millennium of fuzziness.
larsiusprime 6y ago
This seems like a variant of a hypothesis I've heard before: "The universe is old enough, and the rate of expansion of a spacefaring civilization is fast enough (relative to the age of the universe, even at sub-light speeds) that either the aliens should already be here since long ago, or we're the first (or among the first)." ?
- bena 6y ago
  Fermi's paradox. It assumes that technology will get to the point where it becomes trivial to explore space. That's not an easy assumption to grant.
  - larsiusprime 6y ago
    Sure, but my question was just if the article was making the same basic argument as the given hypothesis (along with the same basic assumptions).
  - Pxtl 6y ago
    Trivial and possible are the same. If colonization is possible it will eventually be mastered and then you get geometric growth. Covid has given us all a quick refresher course on the nature of geometric growth. On the timescale of the universe, geometric growth in colonization is functionally hyper rapid. So either colonization (and thus, geometric growth) is impossible or there's nobody else out there.
    - tsimionescu 6y ago
      Well, if establishing colonies and moving from one star system to the next is possible, but takes a few hundred million years each time, then it wouldn't be surprising in any way if even the 'first' civilization to arise has barely colonized a handful of star systems. Perhaps in a few hundred billion years the universe will indeed be full of colonies.
- amelius 6y ago
  How do you determine who was "first" when simultaneity doesn't exist on a cosmic scale?
breck 6y ago
Hubrisimus. Our current models are the most useful ones we have that fit our limited dataset, but we have no clue whether we understand the first thing about space and time and the age and size of the universe(s).
- macintux 6y ago
  What's the alternative to working with the data you have?
  - TheOtherHobbes 6y ago
    There is no alternative to working with the data you have. But believing that you understand the data when there are huge glaring inconsistencies in your understanding is... naive.
    - macintux 6y ago
      I guess I missed the part where this was proclaimed to be Truth.
      - breck 6y ago
        Yeah fair enough I didn't specifically point out the part I was responding to. He says there are only 3 possibilities (the part starting with "then either" 1) ... 2) ... 3) ... But that's ignoring category 4) which is that we have only a fraction of a fraction of a grain of sand of the real data, and might be a bit early to come to conclusions. So not to say #3 is wrong, and heck it could very well be more probably than #1 and #2, but I wouldn't bet the house yet when we don't know if there's an option #4 - #4,000,000,000,000 because we haven't even observed data from dimensions we don't even know exist it.
throwanem 6y ago
Archive link: https://archive.vn/ki5Vm https://archive.vn/ki5Vm
throwanem 6y ago
Robin Hanson is a pretty decent high-concept sf author, and his occasional forays into cosmic horror can be enjoyable too. It's just too bad he ended up in the wrong line of work.
deleted 6y ago
[deleted]
gmuslera 6y ago
How a civilization would expand at the speed of light? Unless it lives directly on the fabric of space or something like that, matter is discrete in the universe. You settle on planets that are not everywhere, or in space stations built with Oort cloud or asteroid belts materials, but it takes time to settle and expand in each new ground you get. You are not talking about the speed of light anymore there. Of course, here I'm trying to think like an alien civilization that is far ahead from us in technology and scientific knowledge, besides having an alien way of thinking, but the same goes for the article. In any case, if that is like any disaster spreading through the universe at the speed of light (big rip?) not only we won't have time to notice, we won't be able to feel the effects neither.
- ctdonath 6y ago
  Think “matter scanner/printer”. Scan an object, at atomic & energy vector level. Transmit that information to a destination’s printer. Expansion is then indeed at speed of light, capped only by need to physically move a small “seed” printer (rapid transport may have enormous energy cost, but that’s all that needs moving; everything else is just data). Having seen tech go from digital imaging to 3D organ printing in a fraction of my lifespan, seems plausible.
  - lisper 6y ago
    But first you have to deliver the printer to the destination somehow.
    - TeMPOraL 6y ago
      Here's an idea. Imagine you have a way to build von Neumann probes that can boost themselves to some high fraction of c (say, 0.9). You start pumping them out in your home system, and send them towards some stars - not necessarily the closest ones. You keep sending them. There's now a shell expanding at 0.9c that's shaped by your production capabilities. Of course, the probes will spend time accelerating and then decelerating towards their destinations. But even as they decelerate, other probes, going to further targets, pass ahead of them. Any probe that lands in a system sets up a facility for building and provisioning more of itself, and sends those to further star systems, adding to the wave. Meanwhile, any technological advancement could be transmitted at the speed of light - so the probes receive improvement instructions as they fly, and the entire shell keeps upgrading itself as it expands. What's the aggregate speed of that shell? Less than 0.9c, I think, but I'd say it's still a high fraction of it. The main warning sign we could look for, assuming there are no crazy unknown physics allowing creation of silent drives, are deceleration plumes and associated thermal emissions. But then, civilizations like ours should be easy to spot from a distance. Don't bother with radio waves, just look at the spectral lines of the planets in a system; if you spot high concentrations of chemicals that don't have geological rationale to be there (such as oxygen in our case), this implies something is keeping the planet away from equilibrium - likely some form of life. If we go by Dark Forest theory, the standard procedure upon detection of such "life signs" would be to send updated instructions to the von Neumann probe heading towards that system: "don't decelerate, ram the planet (or the star) at 0.9 c". If there's anything of use left there, another probe will come later and consume it. So, by the time we spot the evidence of the von Neumann probes, we may just be about to get hit by a relativistic kill vehicle at the vanguard of the expanding shell. (I'm tempted to build a toy model and play with the parameters to see how much of an advance warning we would have.)
ivalm 6y ago
This kind of assumes that a “maxed out” civilization can expand at speed of light, but I don’t think it is given. It may very well be that meaningfully massive transport cannot exceed even a small fraction of c. After all, propulsion has to make energetic sense. 1. There is energy to get to speed 2. Mass of fuel to decelerate (and you have to accelerate that fuel in the beginning!) 3. Highly blue shifted CMB (that alone limits how close to c you can get before becoming plasma) 4. Collision with micrometeorites (so the “ship” has to be microscopic or probability of collision quickly goes to 1, and there is no way to survive even micro collisions while moving at c). 5. Limits on how fast you can give impulse (because your ship is made of matter with finite strength). Eg You cant reasonably railgun something to close to c without converting it to plasma. There is also all the things you do when you get somewhere before sending more probes to expand, presumably it’s not a single location that seeds everything else (and if it is then the energy budget of that is also complicated). Now, even at 0.1 c and with many pauses to replicate on the new worlds it would still take only a few million years to span the milky way, but if someone was mid-expansion we would see them way before the bubble hits. Being limited to 0.1c also means that those not in our galaxy will likely be unable to expand into ours (and vice versa).
- ctdonath 6y ago
  3D printing. Deliver the printer, rest is just information.
  - ivalm 6y ago
    Sure, but printers have mass/volume and require energy. I think in all Van Neumann probe scenarios (which this is) the fact that you bring a micro—replicator that makes other micro-replicators is a given.
    - abecedarius 6y ago
      Right, a bacterium is proof-of-concept for a literally microscopic printer. Maybe the seed to grow into a radio dish out of asteroid materials and sunlight would necessarily be bigger than that, but I'd be surprised if it really had to be bigger than, say... a seed.
ctdonath 6y ago
Analogy: humans have existed for something around 100,000 years, yet we only explored the whole ball - and began affecting it to the point of worrying about making it uninhabitable - within the last few decades. Any lesser culture/species was dominated or destroyed before they could come to grips with the expansion ... not so much because of malice as of “bug vs windshield”.
Gravityloss 6y ago
The anthropic principle is about sampling. It is often counterintuitive to think about sampling problems.
Pazzaz 6y ago
An interesting paper that I don't see brought up often enough is "Dissolving the Fermi Paradox" by Anders Sandberg, Eric Drexler and Toby Ord[0]. They show that it isn't a surprise that we are alone in the universe if we consider the uncertainty inherent to parameters of the Drake equation. Their analysis estimate that there is (at least) a 39% chance that we are alone in the observable universe. [0]: https://arxiv.org/abs/1806.02404 https://arxiv.org/abs/1806.02404
- saberdancer 6y ago
  I really dislike these type of papers. Just like Drake equation, it is all guesswork with completely unknown boundaries for many of the parameters. How will their paper work if we confirm life on Venus, especially if it independently evolved.
- thesteamboat 6y ago
  From a previous discussion of this paper I took away the following clarifying insight: The Drake equation is usually turned into the Fermi paradox via some estimations that show the average (mean) number of alien civilizations we expect to see is large (>1). However, just because the mean is large does not imply that seeing 0 is low probability. More concretely, suppose there were 10 possible 'parallel' universes. In 9 of them humanity is alone and in the tenth there are tens of millions of alien civilizations. The probability of appearing to be alone is 90% even though the number of alien civilizations we'd expect to see is in the millions.
  - krapp 6y ago
    You don't even need to invoke parallel universes. Look at the Hubble Deep Field photo[0]. Our observable universe has hundreds of millions of galaxies. It's entirely feasible for tens of millions of alien civilizations to be spread about and not visible to us in the narrow window of space and time in which we've been looking. [0]https://en.wikipedia.org/wiki/Hubble_Deep_Field https://en.wikipedia.org/wiki/Hubble_Deep_Field
    - thesteamboat 6y ago
skybrian 6y ago
It seems like the argument gets a lot less interesting if the most-expanding interstellar civilizations don't spread at anywhere near the speed of light? It's easy to think of reasons why this might be the case. There is acceleration, deceleration, and replication time, which seems like it would be substantial for any civilization that doesn't want to put most of its resources into replicating as fast as possible.
- rossdavidh 6y ago
  Ah, the classic mistake in a game of "Risk"; expanding as fast as you possibly can, leaving too few resources (troops) at your border to prevent a rapid collapse. If a fast-as-you-can civilization meets a slowly-expanding civilization, it is not at all clear to me that the former would prevail.
  - throwaway-571 6y ago
    In rsk everybody is at a roughly similar technological level. it really depends on things like technological level difference (ask the mayas and aztec) and philosophy, and if you're expanding as fast as you can, you can probably mobilize resources rather easily. Then you have philosophical difference: are you expanding to make friends, or just to gather resources for the hive queen?
ehutch79 6y ago
What's this about? Fnords? After two paragraphs, i'm not sure if this is a real article or a diary entry
antiquark 6y ago
This sounds like the grey goo problem [1], but at a cosmic scale and at (near) the speed of light. Like other commenters have already said, this scenario assumes that near-speed-of-light travel is workable. [1] https://en.wikipedia.org/wiki/Gray_goo https://en.wikipedia.org/wiki/Gray_goo
piker 6y ago
Huh? > Only when the sphere’s thin outer shell had reached the earth—perhaps carrying radio signals from the extraterrestrials’ early history, before their rapid expansion started. By that point, though, the expanding sphere itself would be nearly upon us! Wouldn't the problematic portion of the sphere be, by definition, millions of years away from us? Given that radio waves travel at the speed of light, and the alien civilization travels at slightly less than the speed of light, it seems like we should have at least however many million years it took for those aliens to get from producing radio waves to "maxing out" travel.
- T-A 6y ago
  The first radio transmission by humans was made in 1895. It took another 74 years for humans to land on the moon. It would be disappointing if our augmented and/or artificial descendants really needed millions more years to reach beyond the solar system.
  - piker 6y ago
    Right, but that was sparse and unlikely to be detected, and the author is talking about the portions of the sphere which travel at near speed of light catching up to earth. If human progress is measured on the scale of reaching near-speed-of-light travel, it is easy to imagine being thousands if not millions of years off.
tpoacher 6y ago
Wa there really such a big need for such a clickbait title? Now I'll never know what it was about. Probably someone selling stuff.
- AnimalMuppet 6y ago
  You could either read the article or read the comments. (If there aren't any, wait until there are and read them.) But don't do what you did, which is make a completely uninformative comment. Even if the article is clickbait, and therefore a waste of everybody's time, don't add to the waste with comments like yours.
  - tpoacher 6y ago
    On the contrary. If the author sees my comment and the clickbait was unintentional, then they'll be informed of its grave consequences. On the other hand, if it was intentional, then they'll be informed that it doesn't necessarily work as expected. You might as well claim that "The Social Dilemma" was spam because you can just choose not to open facebook today.
gautamcgoel 6y ago
The ideas discussed in his post, especially the idea of rapidly expanding spheres of civilizations consuming all resources in their path, were beautifully explored in Stephen Baxter's sci-fi book, Manifold: Space (a spin-off of his earlier book, Manifold: Time, which is also excellent). In his book, alien intelligences are common; once they become sufficiently advanced, their civilizations tend to rapidly expand and consume all available resources, often to the detriment of other civilizations in their path. This pattern leads to some interesting phenomena: first, while the night sky might seem quiet at first, once we do encounter aliens, we tend to see their signals across many star systems in rapid succession. The reason is pretty obvious: there is only a brief period of time when we are on the surface of a sphere - a few years after our first observations of aliens, we are engulfed within their sphere and observe their signals from all over our stellar neighborhood. Another idea he plays with is the idea of "refugee" species, who attempt to flee oncoming spheres by evacuating ahead of their path instead of being consumed. Actually, he pushes this idea even further: in the book, our solar system was already engulfed in a few spheres millions of years ago. He suggests that this why Venus is such a hellscape: the aliens came, took the resources they wanted, and left behind a polluted mess. In the case of Venus, they left lots of greenhouse gases behind as the result of some chemical process used to extract resources; as a result, Venus quickly became the warmest planet in the solar system. It's a fun twist on the Fermi paradox: signs of aliens are actually all around us, we are just too dumb to notice them. Another interesting idea he explores a bit is "ownership" of resources. Do the resource-rich asteroids in our solar system really belong to us? Or are they available to any alien race who happens to pass through? In the book, we first notice aliens by observing unexplainable infrared radiation from the asteroid belt (later revealed to be thermal emissions from their resource extraction). He suggests that these aliens will potentially crowd out humans; even if they are not overtly hostile, they could gobble up all the resources we would have used to expand our civilization. Highly recommend this book.
philipkglass 6y ago
Notice that, in Robin’s scenario, the present epoch of the universe is extremely special: it’s when civilizations are just forming, when perhaps a few of them will achieve technological liftoff, but before one or more of the civilizations has remade the whole of creation for its own purposes. Now is the time when the early intelligent beings like us can still look out and see quadrillions of stars shining to no apparent purpose, just wasting all that nuclear fuel in a near-empty cosmos, waiting for someone to come along and put the energy to good use. This presumes that The Most Technologically Advanced Civilization sees virgin nature as nothing but raw material waiting to become something useful. That's possible, but probable? I think that it's likely that diminishing marginal utility still holds even for TMTAC, and therefore they are disinclined to convert all the universe's visible matter and energy into Dyson swarms of Space Product. My favorite (not particularly testable) solution to the Fermi paradox is that TMTAC originated shortly after the first heavy elements and planets formed. It became space faring and expanded throughout the visible universe before our solar system formed. Its agents have been lurking in our solar system since before life first appeared here. Having long ago achieved immortality and technological supremacy, there's no motivation for plundering or trading with terrestrial creatures. They silently observe like space faring bird watchers. They'll intervene if/when we start to approach the capabilities of TMTAC, particularly if we show destructive paperclip-maximizer inclinations toward converting the universe into Space Product. To borrow some terminology from Nick Bostrom's Superintelligence book, it's possible that the universe has been colonized by a singleton civilization -- the first one to become star faring. But it's not particularly chatty or inclined to let potentially competing star faring civilizations expand.
gone35 6y ago
Below [1] Hanson explains some of the details of the argument in length. https://www.youtube.com/watch?v=Rjm--7t8Llk&feature=youtu.be https://www.youtube.com/watch?v=Rjm--7t8Llk&feature=youtu.be
shele 6y ago
So in any case I agree that the world needs to get its shit together and thinking about it: I have never really considered to give it a serious try to make/contribute to make that happen.
chronolitus 6y ago
I like to imagine that this is how things would look if we entered a Karadashev type III civilization's light cone: One day, in a small quadrant of the galaxy, we'd notice starts "shutting off", simply going dark. After a few months, our astonomers would confirm their new model: the amount of stars going dark is increasing. Days later: the rate of increase itself, is increasing. One day we'd wake up, and a small portion of the night sky would be dark. A disk of darkness, right at the brightest part of the galactic plane. By then we would have figured it out of course: most stars in the galaxy were being turned into dyson spheres. They were spreading almost as fast as light, making it look almost instantaneous, even though the process had taken hundreds of thousands of years. In a few thousand years a large portion of our sky would be dark. And after that...
- hagmonk 6y ago
  This is approximately one of the opening ideas in the Commonwealth Saga by Peter Hamilton. Highly recommended!
- ncmncm 6y ago
  Doesn't it seem kind of stupid that a K-III civilization would depend on collecting starlight for energy? Even the most extreme-primitive cultures, barely off their home planet, will have mastered controlled fusion. Almost immediately, they have no more use for small rocky gravity-well planets, or even for stars. They live in Oort clouds where thermal noise is low and cold is plentiful.
  - saberdancer 6y ago
    I agree. It seems very shortsighted to assume a highly advanced civilization would act in this way. Not only would creating Dyson Spheres be extremely visible (Dark Forest comes to mind), but I doubt that these type of civilizations would be energy constrained. Simple fusion reactor solves most of the energy issues.
    - schwartzworld 6y ago
      Maybe Dyson spheres as farms? Fusion wouldn't produce food.
deleted 6y ago
[deleted]
nostrademons 6y ago
Another interesting idea I've been playing with is that there's no guarantee that the lifeform that replaces us will be the same level of complexity. What does it feel like to be a molecule? A mitochondria? A cell? All of these are or were once self-contained "things", but now they exist as part of larger systems. Our image of the beings that replace us tends to look like us and be roughly the same size - robots or little green men. But what if the thing that replaces us encompasses us, so that individual humans become cells in a giant superorganism. There's some evidence that this is already happening - with 6 billion humans on earth, the global economy is already showing specialization (similar to how cells develop into organs in a human) and complex emergent behavior, with parts of it dying off without killing the whole. What if the reason are experience looks like it does, with life a full 1/4 of the age of the universe, because at later points in the universe's evolution, life at this scale becomes meaningless and the primary sentient beings are planetary civilization interacting at the speed of light through the galaxy? Or galactic civilizations interacting throughout the universe?
- sangnoir 6y ago
  The is an interesting take on a superorganism in Venor Vinge's A Fire Upon the Deep
5nlight 6y ago
If you look carefully enough at the implications of our situation through the lens of the 2nd law of thermodynamics, the Fermi paradox becomes a lot less paradoxical. Edit: Apparently I have violated a HN taboo in even daring to mention that bothersome little law. Understanding it and its implications and applying that knowledge to our IRL situation on earth might not be fun, however IS fundamental to making plausible statements about perpetual motion and related topics (i.e."von Neumann probes.") Now, all that remains to be seen, this being HN, is: Will this comment be downvoted into oblivion without a good reason being proferred?
lebuffon 6y ago
Or... is it possible that we are not supposed to meet the "others? Consider: If you wanted to build a "terrarium" for sentient evolving life forms how would you keep them from escaping? 1. Make the distances really really big 2. Put a speed limit in the environment Rolled up with the Fermi paradox this simulation has "smelled fishy" to me for some time. :)
- Frypa 6y ago
  > 1. Make the distances really really big 2. Put a speed limit in the environment Or 3. Don't give humans capabilities to see them. Hell, I'd go even further, what if the "others" are already living on our planet, but we can't see them?
gpsx 6y ago
This may be beside the point, but I don't think there is any alien lift out there. I am going to make up number N_life_universes which is the number of universes needed in order for an instance of intelligent life to evolve. Many people seem to assume this much less than one. I think it is much greater than one, meaning most universes you look at will be void of life. I'd also say there are many universes, one source being the rules of quantum mechanics. But I know some people believe in wave function collapse, and if that is true I am not sure what this means for having mulitple universe. There is a related number, N_hamlet_universes. This is the number of universes needed in order for monkeys to type Hamlet typing as fast as they can, covering every planet spaced 6' feet apart (in case one gets sick). I think this is also a very large number but I haven't figured it out.
oxinabox 6y ago
Interstate idea. The title overstated too late though. Following the premise that an expanding civilization is expanding near the speed of light and it's radio will reach us first. We can expect hundreds of years between radio and anything physical. 1) We started producing a lot of radio around 100 years ago. And we are still a long way from expanding at near speed of light. Even with expodential growth in capacity. 2) expanding near speed of light is much less than speed of light. Say 99% of the speed of light. And expanding civilization is probably going to be coming from far far away, just because there is a lot more far far away than pretty close. So say they are comiy from 10,000 light-years away (still close by galactic standards, and incredibly Close by Universal standards). Then the radio they start transmitting when their grown begins has gained on their expansion ba lead of 100years by the time it reaches us Sure on the million and billion year time-scales mostly talking about that 100+ years is very little but it is still generations.
cbushko 6y ago
I have not studied this area of science but the article reminded me of the fictional book series The Three-Body Problem by Liu Cixin. I really don't want to say anything to spoil the books but the series were so good that I devoured them last summer which is something I rarely do.
ncmncm 6y ago
We don't see aliens because we are looking wrong. They're probably right there. http://cantrip.org/slow.pdf http://cantrip.org/slow.pdf
fao_ 6y ago
For a long time I've figured that the Fermi Paradox is not much of a paradox. Open question: Are we likely to be able to detect the difference between large asteroids and a small swarm of habitable environments in a star. And the second question is: Is it worth spreading out? An advanced civilisation can defend against or modify (maybe even focus) the damage that an imploding star would cause, and an Issac Arthur video on the topic of the amount of space we have in the solar system states clearly that there's more than enough for trillions of trillions of trillions of habitats. There doesn't seem to be much reason for spreading a civilization out whatsoever, given the cost of communication and the assumed cultural and informational lag between the settlement and the source civilization. As the article states, it's unlikely to be the case that we see an expansive civilization until it's too late.
fallingfrog 6y ago
This is extrapolation from an extremely small set of facts, and tremendously conjectural assumptions. It’s the kind of thing you might expect to see from a person living in a civilization that just discovered electrons 200 years ago. Come back to me in 100 years once the economy and population has reached some kind of steady state and then let’s revisit some of these claims. A lot of what we think is rational discourse is actually ingrained, unspoken ideology floating to the surface and being coated with a patina of post hoc rationalization. That’s why it’s so hard to do science properly, especially social science- people don’t even know that they have biases, let alone what they are. But biases aren’t something you can point at directly and say, this belief is not true, it’s more that you might be overestimating the probability of truth of a whole bunch of little things by 10 percent and that creates a self reinforcing network of probable facts that adds up to weird beliefs when they are all put together. The author of the article believes on some deep level that progress is inevitable and will go on indefinitely, combined with the unconscious imagery of a lifetime watching science fiction films, and a life of watching progressively more impressive gadgets appear on store shelves. It all adds up to essays like this.
bserge 6y ago
We're just not looking hard enough. It might seem like a ton of money has been poured into it, but space tech and especially monitoring is so underfunded that it could be a joke when compared against anything else. Any entertainment industry on its own has more funding than all of humanity's space pursuits. All the apps for tracking time, buying clothes, losing weight, scanning tomatoes, properly wiping, get more money than the ESA or JAXA (at least NASA has more than them heh). All the speculation and dreams of a great space colonization are nice, but the reality is that most of us will die on this planet, and likely take half of the life on it with us.
gadtfly 6y ago
Paper: https://arxiv.org/abs/2102.01522 https://arxiv.org/abs/2102.01522 HN discussion of paper: https://news.ycombinator.com/item?id=26045731 https://news.ycombinator.com/item?id=26045731

145 points by gadtfly 6y ago

Even if we do have young competitors like us, they could still be millions of years older than us- the blink of an eye, in a planet’s lifecycle. But millions of years of technological evolution is plenty enough time to make grey goo (or light speed spheres of incoming civilization).

dfabulich 6y ago

The site appears to be down. (504 Gateway Timeout) https://archive.is/ki5Vm https://archive.is/ki5Vm

isoprophlex 6y ago

This is the most profound thing I've read in a while. I'm tempted to whip up some numerical simulation to verify this to some extent... > But here’s the interesting part: conditioned on all the steps having succeeded, we should find ourselves near the end of the useful lifetime of our planet’s star—simply because the more time is available on a given planet, the better the odds there. I.e., look around the universe and you should find that, on most of the planets where evolution achieves all the steps, it nearly runs out the planet’s clock in doing so.

Gupie 6y ago
But we had a billion years left. We have plenty of time to do whether we are going to do before the "planets clock runs out".
- nojokes 6y ago
  and we just getting started.
bpodgursky 6y ago
Robin has done a fair bit of numerical simulation on his OP posts here https://www.overcomingbias.com/2020/12/how-far-aggressive-aliens-part-2.html/ https://www.overcomingbias.com/2020/12/how-far-aggressive-al..., and says he'll have an actual paper out in a week or two.
- isoprophlex 6y ago
  Thanks! Looking forward to reading the paper..!
btilly 6y ago
Want something scary? The form of reasoning used is exactly that in the https://en.wikipedia.org/wiki/Doomsday_argument https://en.wikipedia.org/wiki/Doomsday_argument for why humanity is unlikely to last long, and almost certainly will not have a future where we break out and colonize most of the Solar System, let alone the stars. If you believe both arguments, the most likely outcome is that there is one more step on the way to Robin's argument. And that outcome is the replacement of biological intelligence with mechanical. So indeed we give rise to an expanding wave of technological civilization. But we are close to peak population and will not ourselves see that civilization. All hail our future AI overlords!
- bob33212 6y ago
  We are within 500 years of creating millions of self sustaining spaceports. We are within 500 years of AGI. We are within 500 years of understanding quantum gravity. We are within 500 years of fixing biological death. The order we get to those and how they interplay and change the world matters so much that it doesn't make sense to worry about making predictions.
  - AnimalMuppet 6y ago
    You state these "we are within 500 years" as if they are certainties, but you show no evidence for any of them. The only one I consider even slightly likely is that we are within 500 years of understanding quantum gravity. So... evidence? Argument? Just stating baldly that it is so is not very convincing.
    - bob33212 6y ago
      I don't have a time machine so no I cannot prove what will happen in the future
      - AnimalMuppet 6y ago
        Fine, but you seem to regard it as at least virtually certain. Why? What is your basis for regarding it as close to certain?

chmod600 6y ago

Even in case #3, is it reasonable to assume that the aliens would expand in 3 dimensions at the speed of light? And even of that is true, wouldn't we expect a significant fuzziness in that on the order of a millenium, where we see signs but haven't yet been engulfed?

Gupie 6y ago
But if a civilization has been expanding for a billon years the chances very small that you are this millennium of fuzziness.

larsiusprime 6y ago

This seems like a variant of a hypothesis I've heard before: "The universe is old enough, and the rate of expansion of a spacefaring civilization is fast enough (relative to the age of the universe, even at sub-light speeds) that either the aliens should already be here since long ago, or we're the first (or among the first)." ?

bena 6y ago
Fermi's paradox. It assumes that technology will get to the point where it becomes trivial to explore space. That's not an easy assumption to grant.
- larsiusprime 6y ago
  Sure, but my question was just if the article was making the same basic argument as the given hypothesis (along with the same basic assumptions).
- Pxtl 6y ago
  Trivial and possible are the same. If colonization is possible it will eventually be mastered and then you get geometric growth. Covid has given us all a quick refresher course on the nature of geometric growth. On the timescale of the universe, geometric growth in colonization is functionally hyper rapid. So either colonization (and thus, geometric growth) is impossible or there's nobody else out there.
  - tsimionescu 6y ago
    Well, if establishing colonies and moving from one star system to the next is possible, but takes a few hundred million years each time, then it wouldn't be surprising in any way if even the 'first' civilization to arise has barely colonized a handful of star systems. Perhaps in a few hundred billion years the universe will indeed be full of colonies.
amelius 6y ago
How do you determine who was "first" when simultaneity doesn't exist on a cosmic scale?

breck 6y ago

Hubrisimus. Our current models are the most useful ones we have that fit our limited dataset, but we have no clue whether we understand the first thing about space and time and the age and size of the universe(s).

macintux 6y ago
What's the alternative to working with the data you have?
- TheOtherHobbes 6y ago
  There is no alternative to working with the data you have. But believing that you understand the data when there are huge glaring inconsistencies in your understanding is... naive.
  - macintux 6y ago
    I guess I missed the part where this was proclaimed to be Truth.
    - breck 6y ago
      Yeah fair enough I didn't specifically point out the part I was responding to. He says there are only 3 possibilities (the part starting with "then either" 1) ... 2) ... 3) ... But that's ignoring category 4) which is that we have only a fraction of a fraction of a grain of sand of the real data, and might be a bit early to come to conclusions. So not to say #3 is wrong, and heck it could very well be more probably than #1 and #2, but I wouldn't bet the house yet when we don't know if there's an option #4 - #4,000,000,000,000 because we haven't even observed data from dimensions we don't even know exist it.

throwanem 6y ago

Archive link: https://archive.vn/ki5Vm https://archive.vn/ki5Vm

throwanem 6y ago

Robin Hanson is a pretty decent high-concept sf author, and his occasional forays into cosmic horror can be enjoyable too. It's just too bad he ended up in the wrong line of work.

deleted 6y ago

[deleted]

gmuslera 6y ago

How a civilization would expand at the speed of light? Unless it lives directly on the fabric of space or something like that, matter is discrete in the universe. You settle on planets that are not everywhere, or in space stations built with Oort cloud or asteroid belts materials, but it takes time to settle and expand in each new ground you get. You are not talking about the speed of light anymore there. Of course, here I'm trying to think like an alien civilization that is far ahead from us in technology and scientific knowledge, besides having an alien way of thinking, but the same goes for the article. In any case, if that is like any disaster spreading through the universe at the speed of light (big rip?) not only we won't have time to notice, we won't be able to feel the effects neither.

ctdonath 6y ago
Think “matter scanner/printer”. Scan an object, at atomic & energy vector level. Transmit that information to a destination’s printer. Expansion is then indeed at speed of light, capped only by need to physically move a small “seed” printer (rapid transport may have enormous energy cost, but that’s all that needs moving; everything else is just data). Having seen tech go from digital imaging to 3D organ printing in a fraction of my lifespan, seems plausible.
- lisper 6y ago
  But first you have to deliver the printer to the destination somehow.
  - TeMPOraL 6y ago
    Here's an idea. Imagine you have a way to build von Neumann probes that can boost themselves to some high fraction of c (say, 0.9). You start pumping them out in your home system, and send them towards some stars - not necessarily the closest ones. You keep sending them. There's now a shell expanding at 0.9c that's shaped by your production capabilities. Of course, the probes will spend time accelerating and then decelerating towards their destinations. But even as they decelerate, other probes, going to further targets, pass ahead of them. Any probe that lands in a system sets up a facility for building and provisioning more of itself, and sends those to further star systems, adding to the wave. Meanwhile, any technological advancement could be transmitted at the speed of light - so the probes receive improvement instructions as they fly, and the entire shell keeps upgrading itself as it expands. What's the aggregate speed of that shell? Less than 0.9c, I think, but I'd say it's still a high fraction of it. The main warning sign we could look for, assuming there are no crazy unknown physics allowing creation of silent drives, are deceleration plumes and associated thermal emissions. But then, civilizations like ours should be easy to spot from a distance. Don't bother with radio waves, just look at the spectral lines of the planets in a system; if you spot high concentrations of chemicals that don't have geological rationale to be there (such as oxygen in our case), this implies something is keeping the planet away from equilibrium - likely some form of life. If we go by Dark Forest theory, the standard procedure upon detection of such "life signs" would be to send updated instructions to the von Neumann probe heading towards that system: "don't decelerate, ram the planet (or the star) at 0.9 c". If there's anything of use left there, another probe will come later and consume it. So, by the time we spot the evidence of the von Neumann probes, we may just be about to get hit by a relativistic kill vehicle at the vanguard of the expanding shell. (I'm tempted to build a toy model and play with the parameters to see how much of an advance warning we would have.)

ivalm 6y ago

This kind of assumes that a “maxed out” civilization can expand at speed of light, but I don’t think it is given. It may very well be that meaningfully massive transport cannot exceed even a small fraction of c. After all, propulsion has to make energetic sense. 1. There is energy to get to speed 2. Mass of fuel to decelerate (and you have to accelerate that fuel in the beginning!) 3. Highly blue shifted CMB (that alone limits how close to c you can get before becoming plasma) 4. Collision with micrometeorites (so the “ship” has to be microscopic or probability of collision quickly goes to 1, and there is no way to survive even micro collisions while moving at c). 5. Limits on how fast you can give impulse (because your ship is made of matter with finite strength). Eg You cant reasonably railgun something to close to c without converting it to plasma. There is also all the things you do when you get somewhere before sending more probes to expand, presumably it’s not a single location that seeds everything else (and if it is then the energy budget of that is also complicated). Now, even at 0.1 c and with many pauses to replicate on the new worlds it would still take only a few million years to span the milky way, but if someone was mid-expansion we would see them way before the bubble hits. Being limited to 0.1c also means that those not in our galaxy will likely be unable to expand into ours (and vice versa).

ctdonath 6y ago
3D printing. Deliver the printer, rest is just information.
- ivalm 6y ago
  Sure, but printers have mass/volume and require energy. I think in all Van Neumann probe scenarios (which this is) the fact that you bring a micro—replicator that makes other micro-replicators is a given.
  - abecedarius 6y ago
    Right, a bacterium is proof-of-concept for a literally microscopic printer. Maybe the seed to grow into a radio dish out of asteroid materials and sunlight would necessarily be bigger than that, but I'd be surprised if it really had to be bigger than, say... a seed.

ctdonath 6y ago

Analogy: humans have existed for something around 100,000 years, yet we only explored the whole ball - and began affecting it to the point of worrying about making it uninhabitable - within the last few decades. Any lesser culture/species was dominated or destroyed before they could come to grips with the expansion ... not so much because of malice as of “bug vs windshield”.

Gravityloss 6y ago

The anthropic principle is about sampling. It is often counterintuitive to think about sampling problems.

Pazzaz 6y ago

An interesting paper that I don't see brought up often enough is "Dissolving the Fermi Paradox" by Anders Sandberg, Eric Drexler and Toby Ord[0]. They show that it isn't a surprise that we are alone in the universe if we consider the uncertainty inherent to parameters of the Drake equation. Their analysis estimate that there is (at least) a 39% chance that we are alone in the observable universe. [0]: https://arxiv.org/abs/1806.02404 https://arxiv.org/abs/1806.02404

saberdancer 6y ago
I really dislike these type of papers. Just like Drake equation, it is all guesswork with completely unknown boundaries for many of the parameters. How will their paper work if we confirm life on Venus, especially if it independently evolved.
thesteamboat 6y ago
From a previous discussion of this paper I took away the following clarifying insight: The Drake equation is usually turned into the Fermi paradox via some estimations that show the average (mean) number of alien civilizations we expect to see is large (>1). However, just because the mean is large does not imply that seeing 0 is low probability. More concretely, suppose there were 10 possible 'parallel' universes. In 9 of them humanity is alone and in the tenth there are tens of millions of alien civilizations. The probability of appearing to be alone is 90% even though the number of alien civilizations we'd expect to see is in the millions.
- krapp 6y ago
  You don't even need to invoke parallel universes. Look at the Hubble Deep Field photo[0]. Our observable universe has hundreds of millions of galaxies. It's entirely feasible for tens of millions of alien civilizations to be spread about and not visible to us in the narrow window of space and time in which we've been looking. [0]https://en.wikipedia.org/wiki/Hubble_Deep_Field https://en.wikipedia.org/wiki/Hubble_Deep_Field
  - thesteamboat 6y ago

skybrian 6y ago

It seems like the argument gets a lot less interesting if the most-expanding interstellar civilizations don't spread at anywhere near the speed of light? It's easy to think of reasons why this might be the case. There is acceleration, deceleration, and replication time, which seems like it would be substantial for any civilization that doesn't want to put most of its resources into replicating as fast as possible.

rossdavidh 6y ago
Ah, the classic mistake in a game of "Risk"; expanding as fast as you possibly can, leaving too few resources (troops) at your border to prevent a rapid collapse. If a fast-as-you-can civilization meets a slowly-expanding civilization, it is not at all clear to me that the former would prevail.
- throwaway-571 6y ago
  In rsk everybody is at a roughly similar technological level. it really depends on things like technological level difference (ask the mayas and aztec) and philosophy, and if you're expanding as fast as you can, you can probably mobilize resources rather easily. Then you have philosophical difference: are you expanding to make friends, or just to gather resources for the hive queen?

ehutch79 6y ago

What's this about? Fnords? After two paragraphs, i'm not sure if this is a real article or a diary entry

antiquark 6y ago

This sounds like the grey goo problem [1], but at a cosmic scale and at (near) the speed of light. Like other commenters have already said, this scenario assumes that near-speed-of-light travel is workable. [1] https://en.wikipedia.org/wiki/Gray_goo https://en.wikipedia.org/wiki/Gray_goo

piker 6y ago

Huh? > Only when the sphere’s thin outer shell had reached the earth—perhaps carrying radio signals from the extraterrestrials’ early history, before their rapid expansion started. By that point, though, the expanding sphere itself would be nearly upon us! Wouldn't the problematic portion of the sphere be, by definition, millions of years away from us? Given that radio waves travel at the speed of light, and the alien civilization travels at slightly less than the speed of light, it seems like we should have at least however many million years it took for those aliens to get from producing radio waves to "maxing out" travel.

T-A 6y ago
The first radio transmission by humans was made in 1895. It took another 74 years for humans to land on the moon. It would be disappointing if our augmented and/or artificial descendants really needed millions more years to reach beyond the solar system.
- piker 6y ago
  Right, but that was sparse and unlikely to be detected, and the author is talking about the portions of the sphere which travel at near speed of light catching up to earth. If human progress is measured on the scale of reaching near-speed-of-light travel, it is easy to imagine being thousands if not millions of years off.

tpoacher 6y ago

Wa there really such a big need for such a clickbait title? Now I'll never know what it was about. Probably someone selling stuff.

AnimalMuppet 6y ago
You could either read the article or read the comments. (If there aren't any, wait until there are and read them.) But don't do what you did, which is make a completely uninformative comment. Even if the article is clickbait, and therefore a waste of everybody's time, don't add to the waste with comments like yours.
- tpoacher 6y ago
  On the contrary. If the author sees my comment and the clickbait was unintentional, then they'll be informed of its grave consequences. On the other hand, if it was intentional, then they'll be informed that it doesn't necessarily work as expected. You might as well claim that "The Social Dilemma" was spam because you can just choose not to open facebook today.

gautamcgoel 6y ago

The ideas discussed in his post, especially the idea of rapidly expanding spheres of civilizations consuming all resources in their path, were beautifully explored in Stephen Baxter's sci-fi book, Manifold: Space (a spin-off of his earlier book, Manifold: Time, which is also excellent). In his book, alien intelligences are common; once they become sufficiently advanced, their civilizations tend to rapidly expand and consume all available resources, often to the detriment of other civilizations in their path. This pattern leads to some interesting phenomena: first, while the night sky might seem quiet at first, once we do encounter aliens, we tend to see their signals across many star systems in rapid succession. The reason is pretty obvious: there is only a brief period of time when we are on the surface of a sphere - a few years after our first observations of aliens, we are engulfed within their sphere and observe their signals from all over our stellar neighborhood. Another idea he plays with is the idea of "refugee" species, who attempt to flee oncoming spheres by evacuating ahead of their path instead of being consumed. Actually, he pushes this idea even further: in the book, our solar system was already engulfed in a few spheres millions of years ago. He suggests that this why Venus is such a hellscape: the aliens came, took the resources they wanted, and left behind a polluted mess. In the case of Venus, they left lots of greenhouse gases behind as the result of some chemical process used to extract resources; as a result, Venus quickly became the warmest planet in the solar system. It's a fun twist on the Fermi paradox: signs of aliens are actually all around us, we are just too dumb to notice them. Another interesting idea he explores a bit is "ownership" of resources. Do the resource-rich asteroids in our solar system really belong to us? Or are they available to any alien race who happens to pass through? In the book, we first notice aliens by observing unexplainable infrared radiation from the asteroid belt (later revealed to be thermal emissions from their resource extraction). He suggests that these aliens will potentially crowd out humans; even if they are not overtly hostile, they could gobble up all the resources we would have used to expand our civilization. Highly recommend this book.

philipkglass 6y ago

Notice that, in Robin’s scenario, the present epoch of the universe is extremely special: it’s when civilizations are just forming, when perhaps a few of them will achieve technological liftoff, but before one or more of the civilizations has remade the whole of creation for its own purposes. Now is the time when the early intelligent beings like us can still look out and see quadrillions of stars shining to no apparent purpose, just wasting all that nuclear fuel in a near-empty cosmos, waiting for someone to come along and put the energy to good use. This presumes that The Most Technologically Advanced Civilization sees virgin nature as nothing but raw material waiting to become something useful. That's possible, but probable? I think that it's likely that diminishing marginal utility still holds even for TMTAC, and therefore they are disinclined to convert all the universe's visible matter and energy into Dyson swarms of Space Product. My favorite (not particularly testable) solution to the Fermi paradox is that TMTAC originated shortly after the first heavy elements and planets formed. It became space faring and expanded throughout the visible universe before our solar system formed. Its agents have been lurking in our solar system since before life first appeared here. Having long ago achieved immortality and technological supremacy, there's no motivation for plundering or trading with terrestrial creatures. They silently observe like space faring bird watchers. They'll intervene if/when we start to approach the capabilities of TMTAC, particularly if we show destructive paperclip-maximizer inclinations toward converting the universe into Space Product. To borrow some terminology from Nick Bostrom's Superintelligence book, it's possible that the universe has been colonized by a singleton civilization -- the first one to become star faring. But it's not particularly chatty or inclined to let potentially competing star faring civilizations expand.

gone35 6y ago

Below [1] Hanson explains some of the details of the argument in length. https://www.youtube.com/watch?v=Rjm--7t8Llk&feature=youtu.be https://www.youtube.com/watch?v=Rjm--7t8Llk&feature=youtu.be

shele 6y ago

So in any case I agree that the world needs to get its shit together and thinking about it: I have never really considered to give it a serious try to make/contribute to make that happen.

chronolitus 6y ago

I like to imagine that this is how things would look if we entered a Karadashev type III civilization's light cone: One day, in a small quadrant of the galaxy, we'd notice starts "shutting off", simply going dark. After a few months, our astonomers would confirm their new model: the amount of stars going dark is increasing. Days later: the rate of increase itself, is increasing. One day we'd wake up, and a small portion of the night sky would be dark. A disk of darkness, right at the brightest part of the galactic plane. By then we would have figured it out of course: most stars in the galaxy were being turned into dyson spheres. They were spreading almost as fast as light, making it look almost instantaneous, even though the process had taken hundreds of thousands of years. In a few thousand years a large portion of our sky would be dark. And after that...

hagmonk 6y ago
This is approximately one of the opening ideas in the Commonwealth Saga by Peter Hamilton. Highly recommended!
ncmncm 6y ago
Doesn't it seem kind of stupid that a K-III civilization would depend on collecting starlight for energy? Even the most extreme-primitive cultures, barely off their home planet, will have mastered controlled fusion. Almost immediately, they have no more use for small rocky gravity-well planets, or even for stars. They live in Oort clouds where thermal noise is low and cold is plentiful.
- saberdancer 6y ago
  I agree. It seems very shortsighted to assume a highly advanced civilization would act in this way. Not only would creating Dyson Spheres be extremely visible (Dark Forest comes to mind), but I doubt that these type of civilizations would be energy constrained. Simple fusion reactor solves most of the energy issues.
  - schwartzworld 6y ago
    Maybe Dyson spheres as farms? Fusion wouldn't produce food.

deleted 6y ago

[deleted]

nostrademons 6y ago

Another interesting idea I've been playing with is that there's no guarantee that the lifeform that replaces us will be the same level of complexity. What does it feel like to be a molecule? A mitochondria? A cell? All of these are or were once self-contained "things", but now they exist as part of larger systems. Our image of the beings that replace us tends to look like us and be roughly the same size - robots or little green men. But what if the thing that replaces us encompasses us, so that individual humans become cells in a giant superorganism. There's some evidence that this is already happening - with 6 billion humans on earth, the global economy is already showing specialization (similar to how cells develop into organs in a human) and complex emergent behavior, with parts of it dying off without killing the whole. What if the reason are experience looks like it does, with life a full 1/4 of the age of the universe, because at later points in the universe's evolution, life at this scale becomes meaningless and the primary sentient beings are planetary civilization interacting at the speed of light through the galaxy? Or galactic civilizations interacting throughout the universe?

sangnoir 6y ago
The is an interesting take on a superorganism in Venor Vinge's A Fire Upon the Deep

5nlight 6y ago

If you look carefully enough at the implications of our situation through the lens of the 2nd law of thermodynamics, the Fermi paradox becomes a lot less paradoxical. Edit: Apparently I have violated a HN taboo in even daring to mention that bothersome little law. Understanding it and its implications and applying that knowledge to our IRL situation on earth might not be fun, however IS fundamental to making plausible statements about perpetual motion and related topics (i.e."von Neumann probes.") Now, all that remains to be seen, this being HN, is: Will this comment be downvoted into oblivion without a good reason being proferred?

lebuffon 6y ago

Or... is it possible that we are not supposed to meet the "others? Consider: If you wanted to build a "terrarium" for sentient evolving life forms how would you keep them from escaping? 1. Make the distances really really big 2. Put a speed limit in the environment Rolled up with the Fermi paradox this simulation has "smelled fishy" to me for some time. :)

Frypa 6y ago
> 1. Make the distances really really big 2. Put a speed limit in the environment Or 3. Don't give humans capabilities to see them. Hell, I'd go even further, what if the "others" are already living on our planet, but we can't see them?

gpsx 6y ago

This may be beside the point, but I don't think there is any alien lift out there. I am going to make up number N_life_universes which is the number of universes needed in order for an instance of intelligent life to evolve. Many people seem to assume this much less than one. I think it is much greater than one, meaning most universes you look at will be void of life. I'd also say there are many universes, one source being the rules of quantum mechanics. But I know some people believe in wave function collapse, and if that is true I am not sure what this means for having mulitple universe. There is a related number, N_hamlet_universes. This is the number of universes needed in order for monkeys to type Hamlet typing as fast as they can, covering every planet spaced 6' feet apart (in case one gets sick). I think this is also a very large number but I haven't figured it out.

oxinabox 6y ago

Interstate idea. The title overstated too late though. Following the premise that an expanding civilization is expanding near the speed of light and it's radio will reach us first. We can expect hundreds of years between radio and anything physical. 1) We started producing a lot of radio around 100 years ago. And we are still a long way from expanding at near speed of light. Even with expodential growth in capacity. 2) expanding near speed of light is much less than speed of light. Say 99% of the speed of light. And expanding civilization is probably going to be coming from far far away, just because there is a lot more far far away than pretty close. So say they are comiy from 10,000 light-years away (still close by galactic standards, and incredibly Close by Universal standards). Then the radio they start transmitting when their grown begins has gained on their expansion ba lead of 100years by the time it reaches us Sure on the million and billion year time-scales mostly talking about that 100+ years is very little but it is still generations.

cbushko 6y ago

I have not studied this area of science but the article reminded me of the fictional book series The Three-Body Problem by Liu Cixin. I really don't want to say anything to spoil the books but the series were so good that I devoured them last summer which is something I rarely do.

ncmncm 6y ago

We don't see aliens because we are looking wrong. They're probably right there. http://cantrip.org/slow.pdf http://cantrip.org/slow.pdf

fao_ 6y ago

For a long time I've figured that the Fermi Paradox is not much of a paradox. Open question: Are we likely to be able to detect the difference between large asteroids and a small swarm of habitable environments in a star. And the second question is: Is it worth spreading out? An advanced civilisation can defend against or modify (maybe even focus) the damage that an imploding star would cause, and an Issac Arthur video on the topic of the amount of space we have in the solar system states clearly that there's more than enough for trillions of trillions of trillions of habitats. There doesn't seem to be much reason for spreading a civilization out whatsoever, given the cost of communication and the assumed cultural and informational lag between the settlement and the source civilization. As the article states, it's unlikely to be the case that we see an expansive civilization until it's too late.

fallingfrog 6y ago

This is extrapolation from an extremely small set of facts, and tremendously conjectural assumptions. It’s the kind of thing you might expect to see from a person living in a civilization that just discovered electrons 200 years ago. Come back to me in 100 years once the economy and population has reached some kind of steady state and then let’s revisit some of these claims. A lot of what we think is rational discourse is actually ingrained, unspoken ideology floating to the surface and being coated with a patina of post hoc rationalization. That’s why it’s so hard to do science properly, especially social science- people don’t even know that they have biases, let alone what they are. But biases aren’t something you can point at directly and say, this belief is not true, it’s more that you might be overestimating the probability of truth of a whole bunch of little things by 10 percent and that creates a self reinforcing network of probable facts that adds up to weird beliefs when they are all put together. The author of the article believes on some deep level that progress is inevitable and will go on indefinitely, combined with the unconscious imagery of a lifetime watching science fiction films, and a life of watching progressively more impressive gadgets appear on store shelves. It all adds up to essays like this.

bserge 6y ago

We're just not looking hard enough. It might seem like a ton of money has been poured into it, but space tech and especially monitoring is so underfunded that it could be a joke when compared against anything else. Any entertainment industry on its own has more funding than all of humanity's space pursuits. All the apps for tracking time, buying clothes, losing weight, scanning tomatoes, properly wiping, get more money than the ESA or JAXA (at least NASA has more than them heh). All the speculation and dreams of a great space colonization are nice, but the reality is that most of us will die on this planet, and likely take half of the life on it with us.

gadtfly 6y ago

Paper: https://arxiv.org/abs/2102.01522 https://arxiv.org/abs/2102.01522 HN discussion of paper: https://news.ycombinator.com/item?id=26045731 https://news.ycombinator.com/item?id=26045731