[HN Gopher] Once we can see them, it's too late ___________________________________________________________________ Once we can see them, it's too late Author : gadtfly Score : 80 points Date : 2021-01-30 19:27 UTC (3 hours ago) (HTM) web link (www.scottaaronson.com) (TXT) w3m dump (www.scottaaronson.com) | dfabulich wrote: | The site appears to be down. (504 Gateway Timeout) | https://archive.is/ki5Vm | ehutch79 wrote: | What's this about? Fnords? After two paragraphs, i'm not sure if | this is a real article or a diary entry | antiquark wrote: | 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 | newsbinator wrote: | 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). | chronolitus wrote: | 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... | [deleted] | piker wrote: | 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 wrote: | 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 wrote: | 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. | gmuslera wrote: | 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 wrote: | 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 wrote: | But first you have to deliver the printer to the destination | somehow. | isoprophlex wrote: | 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. | btilly wrote: | Want something scary? | | The form of reasoning used is exactly that in the | 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! | dsr_ wrote: | It's just as likely that we all greet our future AI | grandchildren, as they will be us. | bob33212 wrote: | 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. | Gupie wrote: | 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". | bpodgursky wrote: | Robin has done a fair bit of numerical simulation on his OP | posts here https://www.overcomingbias.com/2020/12/how-far- | aggressive-al..., and says he'll have an actual paper out in a | week or two. | ivalm wrote: | 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). | empiricus wrote: | If we think about the limits of the physical laws, one | possibility is having a civilization that maximizes the | available computation, and I suspect that this looks like some | kind of black hole expanding with the speed of light. | ndjtjgkglf wrote: | In theory you can manipulate atoms and molecules at a distance | with light. | | So you can use a laser beam to construct a 3D printer at a | distance. | | Rinse and repeat, and this is asymptotically expanding at c. | eloff wrote: | A laser beam expanding out over light years is not a laser | anymore and definitely not atom sized. | ndjtjgkglf wrote: | You are assuming present day lasers. An advanced | civilization will individually control the photons. | | You also don't really need atom resolution anyway. You can | build mechanical computers driven by rolling stones by | abblating matter with powerful beams - lithography on | continent size scale, etc. | ctdonath wrote: | 3D printing. | | Deliver the printer, rest is just information. | ivalm wrote: | 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. | xvedejas wrote: | I understood the "close to the speed of light" really meant | something much much smaller than 0.1c, since on cosmological | timescales the difference between the first radio signals and | domination from an alien civilization could be millions of | years, and that'd still be an instant compared to the time | before and after the event. So I'm assuming for the fermi | paradox to work out here, we'd not need speeds anywhere near | 0.1c | ivalm wrote: | If you move slower than 0.1c then you can't really cross | between galaxies (or at least you are limited to very nearby | ones). So we only have to worry about grabby aliens in our | galaxy AND we can be fairly certain that there are currently | none! Since we ourselves are probably only thousands of years | from being grabby this implies we don't have advanced | competitors .This is a very different picture from what | Hansen discusses. | gautamcgoel wrote: | 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. | chmod600 wrote: | 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 wrote: | But if a civilization has been expanding for a billon years the | chances very small that you are this millennium of fuzziness. | philipkglass wrote: | _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. | ctdonath wrote: | 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 wrote: | The anthropic principle is about sampling. It is often | counterintuitive to think about sampling problems. | larsiusprime wrote: | 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)." ? | amelius wrote: | How do you determine who was "first" when simultaneity doesn't | exist on a cosmic scale? | bena wrote: | 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 wrote: | 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 wrote: | 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. | jstanley wrote: | What makes you think we'll be among the first? | | No human being has ever set foot on a different planet. | | No man-made object has ever reached a star system outside our | own, let alone landed on a planet. | | We may still be quite a long way away from accomplishing those | things at scale. | larsiusprime wrote: | I'm just asking if the article is making a similar argument | to the stated hypothesis. | breck wrote: | 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 wrote: | What's the alternative to working with the data you have? | TheOtherHobbes wrote: | 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 wrote: | I guess I missed the part where this was proclaimed to be | Truth. | breck wrote: | 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 wrote: | Archive link: https://archive.vn/ki5Vm | Pazzaz wrote: | 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 | throwanem wrote: | 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. | skybrian wrote: | 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 wrote: | 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. | gone35 wrote: | Below [1] Hanson explains some of the details of the argument in | length. | | https://www.youtube.com/watch?v=Rjm--7t8Llk&feature=youtu.be | tpoacher wrote: | 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. | shele wrote: | 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. ___________________________________________________________________ (page generated 2021-01-30 23:00 UTC)