[HN Gopher] Once we can see them, it's too late
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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.
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