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Galactic Settlement and the Fermi Paradox
- jjaredsimpson 7y agoI believe we are alone in Milky Way. Self assembling replicators from some civilization should have colonized and cataloged every star system over billion year time scales. It's inconceivable that no intelligent space faring civilization would have thought to do this.
- jmmcd 7y agoMaybe they did and it left no trace noticeable to us, or their policy is not to contact life-bearing planets, and did you read the article?
- m4rtink 7y agoAlien ruins would be nice to explore but oh well. If it really is like that, we can at least spread through it in a relative peace. :)
- gnulinux 7y agoMaybe they're in the process of doing that but it just so happened that they haven't cataloged our system yet.
- 3pt14159 7y agoPresuming we're not in a simulation then I think it is unlikely that we're alone in the Milky Way. There are too many stars and too many close enough galaxies that could contain life. If they've been spacefaring for even ten thousand years longer than us then they're almost certainly able to monitor us without our ability to detect it. But if we're doomed to a great filter in the near future, like nuclear war, then it still doesn't mean we're alone. It just means that out there in the sky there are others kinda like us. Searching for meaning before hitting a technological explosion of one kind or another that wipes us out. But just because we don't have contact doesn't mean we're alone, even if we're only present in each others respective imaginations.
- semi-extrinsic 7y agoI've been mulling this over: given the constraints of information travelling at lightspeed and physical objects travelling at a lot less, what if it simply doesn't make financial sense for any actor in a market economy to colonize the galaxy? What if the ROI of space colonization even at multi-decade or multi-century timescales is negative? Then why would anyone do it?
- ncmncm 7y agoMarket economy is far from a law of nature. Even most human activity is cannot be understood as market driven.
- kochikame 7y agoThere doesn't have to be an economic motive What if they just feel like exploring, and gaining knowledge, and seeing things no one else has ever seen?
- semi-extrinsic 7y agoWell, they'd still have to be able to pay for everything they need to go off on that voyage.
- krapp 7y agoIt seems like you're assuming the difficult part about creating self-assembling replicators capable of sustained, error-free exponential growth across interstellar space and billions of years is merely coming up with the idea. It's entirely conceivable that every space faring civilization which has tried has failed simply because the odds are so stacked against success, even once, at every step along that process. Just because the math is simple, doesn't mean the application is simple. Hell, we don't even know what the odds are of becoming a space faring civilization to being with, and it doesn't seem axiomatic that every such civilization would even want to seed the galaxy with self-assembling replicators to begin with.
- rthomas6 7y agoBut what if that happens once every, say, 2 billion years on average? What is the likelihood we exist in a time close enough to that happening for us to be able to find ruins of it? That is the point the article made. There is an assumption that, if that happens, the colonization is permanent. Maybe that's not a good assumption.
- aeternum 7y agoPlot-twist: We are those self-assembling replicators, and DNA/RNA is the deployment mechanism.
- seiferteric 7y agoMaybe we are the colonizers. Perhaps panspermia is the method in which distant civilizations choose to spread through the galaxy.
- ben_w 7y agoMy gut feeling says panspermia is likely occurring regardless of whether Earth life is descended from stuff from other worlds or vice-versa. I don’t expect it to be a deliberate colonial mechanism, thought perhaps it might work as a deliberate terraforming mechanism, as one step in a plan in the vein of Stuart Armstrong’s talk on disassembling Mercury and using it to directly colonise the entire supercluster essentially simultaneously?
- kangnkodos 7y agoWhen we finally build Artificial General Intelligence, they will decide where to shoot the next DNA seeds, and the cycle will begin again.
- ben_w 7y agoYou might want to watch his presentation. We don’t need an AGI to decide, could literally shoot everywhere.
- seiferteric 7y agoMaybe our perspective is just wrong. If you consider that DNA itself is the life on earth, and not "us" in particular and that maybe DNA is the only life possible in this universe then this view makes more sense. Humans could be viewed as just an appendage of DNA.
- yesenadam 7y ago"We are survival machines – robot vehicles blindly programmed to preserve the selfish molecules known as genes. This is a truth which still fills me with astonishment" - Richard Dawkins, The Selfish Gene, 1976 Dawkins talking about the first sentence, about 1980: "...that was no metaphor. I believe it is the literal truth, provided certain key words are defined in the particular ways favoured by biologists. Of course it is a hard truth to swallow at first gulp. As Dr Christopher Evans has remarked, "This horrendous concept - the total prostitution of all animal life, including Man and all his airs and graces, to the blind purposiveness of these minute virus-like substances - is so desperately at odds with almost every other view that Man has of himself, that Dawkins’ book has received a bleak reception in many quarters. Nevertheless his argument is virtually irrefutable" ... http://www.politicsforum.org/forum/viewtopic.php?t=58430 http://www.politicsforum.org/forum/viewtopic.php?t=58430
- irrational 7y agoI don't think we can start wondering about the Fermi Paradox until we actually manage to get humans (or at least a von Neumann probe) to another star system. We are the only intelligent more-or-less spacefaring species that we are aware of and if we can't do it why would we think other hypothetical intelligent spacefaring species can do it.
- metalliqaz 7y agoBecause we went from beating sticks together to manned spaceflight in less than 1x10^4 years. Isn't it fair to extrapolate that to inter-stellar travel in 1x10^6 years?
- irrational 7y agoNo, my gut feeling is that we will never reach another star with humans or a self-replicating probe, so until we do I assume nobody else can/will either.
- scrumper 7y agoThing that's interesting to me is that we have a number of proposals for how we might reach another star with essentially present-day technology. So even us dumb humans think we could get a robot probe out there. A self-replicating one is much further off of course. Are you just questioning the Von Neumann machine aspect or the entire feasibility of sending a basic dumb probe out to another star for a fly-by?
- manicdee 7y agoThere’s a huge technological leap between s tiny laser-propelled fly-by probe and a ship full of humans stopping in that system to settle.
- irrational 7y agoA fly-by doesn't count. Even the Voyager probes will someday fly-by some star. Going to a star and setting up shop (whether a human colony or self-replicating probes) is the only thing that counts in my book.
- keiferski 7y agoMaybe I’m misunderstanding it, but the Fermi Paradox always seemed hopelessly naive and myopic to me. We understand such a small percentage of reality, but more importantly, everything we learn and observe is through our human perspective. It seems more logical to assume that the universe appears empty to us because we are the only organisms like ourselves, and that other life forms exist in ways that are simply incomprehensible to us at the current level of scientific understanding. Edit: To use a metaphor I’ve just thought of (and think works): many people assume that meeting extraterrestrial life will be akin to Europeans landing in the New World. It’s more likely that it will be akin to the discovery of the atom.
- TheOtherHobbes 7y agoAgreed. Assuming we avoid extinction, it's not obvious we'll be able to recognise ourselves a few hundred years from now, never mind a few thousand. And a gulf of a few million years would be utterly incomprehensible. In fact I'd be very suspicious if recognisable alien life appeared and knocked on our door, because it would literally be so astronomically unlikely I'd be skeptical about taking it at face value.
- blacksmith_tb 7y agoWell, yes and no - plenty of terrestrial organisms that haven't shared a common ancestor with us for hundreds of millions of years can recognize us (like, say, crows). But I agree that easily recognizable sentient aliens visiting us in person is very unlikely, due to the scale of the universe.
- jbattle 7y agoI mean sorta. But think about the incredible variety of life on Earth. Read some science fiction. I'm not saying our search space / our expectations are perfectly broad enough. But I've never seen any sign the people involved in SETI are doing this with blinders trying to find bipedal creatures with a mouth that breathes oxygen and are about 1-2 meters tall.
- 7y ago
- ncmncm 7y agoEither of the following suffices to account for the evidence: 1. Expansionist civilizations that encounter one another reliably obliterate one another. Non-expansionists don't spread out. 2. Advanced civilizations have no need for goldielocks-zone planets. Where mass is needed, Kuiper-belt objects are more convenient sources. The notion of Dyson spheres seems especially silly: even extreme primitives would have confined fusion power, and have no need to rely on primitive, diffuse stellar radiation. Both could be true, along with others not listed.
- saltyfamiliar 7y agoWhat if preoccupation with the material world is a primitive perspective that civilizations simply grow out of eventually? There's an inescapable time limit to the universe and it's all objectively pointless anyway. Why spend valuable resources scouting the cold void of space when you can just turtle up on your planet and live 100 lifetimes at .1x speed in VR?
- cm2012 7y agoThe universe is just really, really big. If there's no way to exceed the speed of light it makes perfect sense we haven't detected other life.
- coldtea 7y ago"A spacefaring species could easily settle the entire Milky Way given billions of years" That's somewhat of a wild assumption. What's a "spacefaring species"? Are we one since we've built a few ships and went to the moon? Have they solved problems that might be intractable, like being able to travel anywhere remotely far in anything else than a "generation ship"? Have they found the power to deploy those ships, and the materials (and amounts required of them) to withstand the radiation of space, incoming meteors and space debris over decades of flying, while still being able to propel their spaceships out of their gravity? And why would those settlements even be able to survive in space, going out on some remote systems, and not knowing what they'll find there, and what exactly their Earth-like planets will provide them? >William Newman and Carl Sagan later wrote a major rebuttal to Hart’s work, in which they argued that the timescales to populate the entire galaxy could be quite long. In particular, they noted that the colonization fronts Hart described through the Milky Way might move much more slowly than the speed of the colonization ships if their population growth rates were so low that they only needed to spread to nearby stars very rarely. They also argued that being a long-lived civilization is inconsistent with being a rapidly-expanding one, so any species bent on settling the galaxy would not last long enough to succeed. In other words, they reasoned that the galaxy could be filled with both short-lived rapidly expanding civilizations that don’t get very far and long-lived slowly expanding civilizations that haven’t gotten very far—either way, it’s not surprising that we have not been visited. That sounds much more logical!
- baja_blast 7y agoOne thing I think often gets ignored is the fact advanced civilizations require complex supply chains that would be extremely hard to bring to another planet. If anything goes wrong everyone is wiped out. Also hopping from one planet to the next would require the next planet to develop over a long period before they could start the next generation ship.
- Teever 7y agoThere's no proof that an advanced civilization requires a complex supply chain. In fact one of epochs of technological progression that occurs after an industrial revolution could possibly be an industrial simplification where supply chains and manufacturing processes reach a sort of apex in complexity that leads to absolute simplification. It may just be that such a developmental landmark is a prerequisite of a civilization reaching interplanetary scale and it may even be a great filter.
- axilmar 7y agoWe really can't reach any actual conclusion at this point. We may say today that interstellar travel is impossible, but tomorrow we may find a solution. We may say today that we are alone, only to be visited by intelligent aliens somewhere in the next millennia. We may never be visited by anyone or visit anyone, but the universe may be full of intelligent life. We simply cannot compute anything for such a problem, with so many unknowns.