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Beyond “Fermi’s Paradox”: The Percolation Theory Hypothesis

57 points by headalgorithm 6y ago

molticrystal 6y ago
Thanks for pointing out this series, here is an rss feed for those interested in never missing the next article: https://www.universetoday.com/feed/?s=%22Beyond+%22Fermi%27s+Paradox%22%22 https://www.universetoday.com/feed/?s=%22Beyond+%22Fermi%27s... Or you can broaden the list with some additional articles tagged as related to the Fermi Paradox with: https://www.universetoday.com/tag/fermi-paradox/feed/ https://www.universetoday.com/tag/fermi-paradox/feed/ It seems the author publishes every few weeks to months.
l33tman 6y ago
It's extremely anthropocentric reasoning, like "the cost is too large", "you lose control of the hegemony" etc. And that there are "colonists" that "die off". I'm not sure any of these assumptions are applicable given billions of possible origins of life at various stages of development. Even at Earth, and with extremely conservative estimates, given 100 more years of nanotech/biotech/AI development, we won't die off, and could certainly send autonomous robot probes. When you don't die anymore, 8 years roundtrip (or more) suddenly doesn't seem so long. BTW in the fiction arena, I suggest reading David Brin "Existence" if you're so inclined which is related to this :)
- rm445 6y ago
  Great post, but in the context of "Where is everybody?", each 'we won't' or 'we could', where we haven't actually done it yet, is potentially part of the solution to the puzzle. Perhaps filling the universe with undying, exponentially-spreading probes, that don't stop spreading due to values drift, is harder than we think. (Personally, an early filter feels more likely to me, but if it's not that, it's gotta be something).
- mabbo 6y ago
  > It's extremely anthropocentric reasoning, like "the cost is too large" I'm not sure certain. Cost is, at its core, based on physics- energy, resources and time are the true values all money is based on. Those constraints will exist everywhere in the universe, however they may be treated by an ETI. No matter where you go or who you are, you still need a massive amount of energy to move matter from one star to another.
  - l33tman 6y ago
    Travel doesn't cost any energy, only acceleration and decceleration, so if you accept a slow travel this isn't particularly expensive. Especially with drones you wouldn't need a huge spaceship with environmental systems for squishy bio-masses like humans... :)
    - tsimionescu 6y ago
      That's only true if you're launching a piece of rock. Otherwise, it does cost energy to maintain a system running and, at the very least, tracking time for 10000 years. It's not even obvious that it is theoretically possible with current circuit technologies. Pieces would fuse together, moving parts would erode, all sorts of organic materials might deteriorate, everything would be affected by the huge amount of time. And you would almost certainly need energy to actively fight this entropy so that you would have an active machine when you reach your destination.
      - ganzuul 6y ago
        https://en.wikipedia.org/wiki/Magnetic_logic https://en.wikipedia.org/wiki/Magnetic_logic Iron is nuclear ash, and this tech is just about the most reliable implementation of logic we have. It was used in the V2 rocket and US nuclear submarines. It's abandoned tech though and was never pushed beyond 1MHz. If however you have a decade to compute your reactions then that might not matter. Superconducting magnetic loops also store their flux indefinitely, and in space keeping it cool would be trivial.
  - TheOtherHobbes 6y ago
imtringued 6y ago
It's pretty obvious. Space is harsh. Even just doing colonization within the solar system is hard to swallow. It's not possible to live on most planets even if we assume that everyone stays in what amounts to a grounded space station. Since we have not yet unlocked fusion we will always have to stay close to the sun. Mars is already too far away. Venus has an extreme atmosphere that causes it to be extremely hot. If a crackpot said we have to build a 100000 person colony in space this century we would have to start on the moon even though there is no water there. The primary reason would be that we are still close enough to the sun that we can use solar panels to generate energy. Space colonization without fusion is simply put: a joke. If space was easy then our galaxy would have been devoured by some grey goo AI (not life) a long time ago. Life has to build artificial habitats and live in them. AIs can just stay in space forever as long as they can gather enough resources.
- ben_w 6y ago
  I’m more concerned with the politics than the technology of space colonisation. Space colonisation with current tech isn’t a joke, but it is a folly in the sense of British Victorian-era aristocrats — extremely rich people doing fancy but not very cost-effective things. Fusion isn’t necessary for this, however, as PV scales well enough for a Mars colony (don’t get me wrong, still extremal, but it could be made to work up to about Jupiter if cost of local manufacturing was not a limiting factor). But: politics. Let’s assume every settlement on Earth has a corresponding space habitat (O’Neill cylinder or whatever) of the same population in Earth orbit. With this situation, rapid transport between any two locations is trivial enough that high school students could accidentally blow everything up up — I made an ion drive while at school (simple ones are easy) but orbital dynamics are counter-intuitive and not something a high schooler is likely to know, so a kid running one in space with that many large stations around has a high risk of causing a Kessler cascade. Scale the hypothetical scenario up to a K2 swarm around the sun, same applies only with the risk of mass extinction on the home planet. In either case it can be weaponised, and about 19 years ago a bunch of theocratic fundamentalists demonstrated that a small group of humans can be smart enough to cause enormous harm while also being dumb enough to not predict the consequences.
  - 6y ago
coldcode 6y ago
One problem with determining how a civilization could travel is we only know what we know now or can reasonably speculate. A hundred years ago we didn't really have the ability to even get into orbit much less imaging visiting another star. Today we can imagine ways but they are insanely expensive and likely to take dozens of years or even centuries at best. Assuming constant progress in technology we might be able to get there faster by waiting decades than by leaving now. Even the absolute limit of light speed, while impossible to imagine today, might turn out to be less of on obstacle in some future understanding of physics. It's hard to predict the future since all you have is today's knowledge.
- 7373737373 6y ago
  https://en.wikipedia.org/wiki/Interstellar_travel#Wait_calculation https://en.wikipedia.org/wiki/Interstellar_travel#Wait_calcu... https://www.researchgate.net/publication/260275150_Interstellar_Travel_-_The_Wait_Calculation_and_the_Incentive_Trap_of_Progress https://www.researchgate.net/publication/260275150_Interstel...
- boraoztunc 6y ago
  Thinking the same, for travel and all. After 30+ years of my humble existence in this universe, these are the times I want so badly to see a glimpse of the future, a scene from 10.000 years later. SO, SO curious. Thinking is leading me to nowhere with my limited capacity, dreaming with mostly unrelated fantasies and visions. A real one would be nice, even from the exact location I'm sitting now, the street, the sea nearby, everything around, how they evolved. Mind-blowing universe, amazing planet, very little time sadly.
  - jdmoreira 6y ago
    10.000 years is a lot. In the past that’s roughly when agriculture was invented. In the future chances are humans will be either extinct or living in very though conditions. The future is not necessarily always better. It certainly wasn’t for the grandsons of hunter-gatherers that became farmers
amelius 6y ago
Why explore space when your holodeck has much better content?
- plutonorm 6y ago
  I agree. Technology will soon (within 1000 years) take us to a place where whatever we can imagine we can have in a simulation that is indistinguishable from the real world. Why bother with the real world anymore? There maybe some cultures that still see value in the physical world, but I'd wager not many. I also think it's likely that panspermia is a thing. Life is evolving at the galaxy level, it's therefore a little more reasonable to think that we represent one of the more evolutionarily advanced life forms at the current time.
  - GoblinSlayer 6y ago
    People who see no value in the physical world don't want simulation to be indistinguishable from the real world.
- Enginerrrd 6y ago
  Yeah, I actually think there's a ton of merit to this. Fundamentally, the natural progression of technology for any alien species is probably going to be the capability to backup/restore/copy/enhance their consciousness. Biology is delicate, but a purpose-built computer can be designed to survive under very austere conditions, and offers so many incentives! Under the premise that such technology allows for faster and more robust iteration, it would quickly come to dominate the species within which it originates. At that point though, I think there's a lot of incentive toward looking inward rather than outward as an entity--be it from internal competition to become the dominant intelligent entity within your species, or because you've secured a large store of energy and low entropy to harvest. At some point, your iterations are so fast that, IMO, expanding beyond a certain size is likely to introduce a significant fracturing of that society/entity. Why spend the energy on having to compete with your future self?
hliyan 6y ago
When you consider the potential age of the universe [1], we can also argue that the universe is currently in its extreme infancy and we many in fact be one of the very first civilizations to start thinking about other civilizations, and all other "firstborn" civilizations are similarly constrained by technology. [1] https://en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe https://en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe , more dramatically portrayed in this excellent video: A Journey to the End of Time [2] [2] https://youtu.be/uD4izuDMUQA?t=196 https://youtu.be/uD4izuDMUQA?t=196
- hindsightbias 6y ago
  Evidence points to us having missed all the good parties: https://arxiv.org/abs/2012.07902 https://arxiv.org/abs/2012.07902
- pfdietz 6y ago
  It has been estimated that 95% of the stars that will ever form have already formed. Far from being in its infancy, from the point of view of locations for new life arising the universe is nearly done. https://scitechdaily.com/star-formation-in-the-universe-has-decreased-drastically/ https://scitechdaily.com/star-formation-in-the-universe-has-...
  - soared 6y ago
    But they have existed for a short period of their lifespan, so by definition are early in their lifetimes. The argument isn’t that there will be new stars, but that they will exist for a long time.
    - pfdietz 6y ago
      There's good reason to think life is not going to arise on planets around M stars. Our sun is quite bright compared to the typical star, is already gone through about half its time on the main sequence, and as the Sun continues to brighten the Earth will become uninhabitable in about 1 billion more years. Moreover, life originated early on Earth. This suggests either that more than one extremely rare event is needed to get from life to us, or that the conditions for OoL do not persist for very long (ammonia, for example, is rapidly destroyed by solar radiation.)
GoblinSlayer 6y ago
They assume that a space faring civilization is identical to us down to capitalism, technology, fossil fuel dependency, education, politics, tradition, everything, but this assumption is self defeating: we have all these properties and space travel is infeasible to us, consequently any other civilization that has all the same properties is unable to travel between stars either.
api 6y ago
Interstellar travel is possible with 1960s technology. Search for Project Orion. Thermonuclear Orion could reach as much as 10% the speed of light, which is fast enough to reach the Centauri system in a human life span. Then there is the potential of things like hibernation, or AI that can just turn itself off. The latter would be able to use a less costly but slower propulsion system. I really don’t think travel implausibility works as a Fermi paradox answer. It’s hard but not hard enough to explain the absence of visitors in a galaxy full of planets in habitable zones.
- avian 6y ago
  > Thermonuclear Orion could reach as much as 10% the speed of light I wonder how much such a mission would cost in terms of total Earth resources. I've read Dyson's book on the project some years back and I don't remember that being mentioned. Wikipedia states the cost in percentage of U.S. GDP (0.1 - 1% of yearly GDP), but I feel like the millions of tons of copper and fissile material required would be significant hit on remaining mineral reserves. It's kind of hard to justify sending out a few missions if it means that the planet left behind is out of easily mined copper and uranium deposits.
  - api 6y ago
    It wouldn’t take that much. Fissile material can be bred in fast breeder reactors, and in a thermonuclear Orion type pulse drive most of the power comes from hydrogen fusion. The fissile warheads are primers for each fusion charge. We could probably send a probe to Centauri for the price of one Iraq war. Of course launching “the devil’s pogo stick” from within our biosphere would be rather horrible for the environment. It would be a lot better to build a base on the Moon and launch it from there. You wouldn’t need to burn as much power getting out of a big gravity well. The Moon, being formed from the same stuff as Earth, certainly has fissile material, and it may be closer to the surface and easier to get there. I really think the most likely answer to the Fermi paradox is that extreme intelligence is rare. There probably isn’t a single great filter per se. It’s probably just unlikely for an environment to be simultaneously stable enough over billions of years to produce high intelligence and interesting enough to stimulate its evolution. Most interesting environments will be unstable, and most stable environments uninteresting (a.k.a. having low Shannon information content). The universe is probably full of microbes, simple microbial colonies, and maybe a few worms and bugs, but there are probably not very many minds around capable of harnessing the atom and plotting orbital trajectories. Fewer still may have the motivation to invest in such an epic and likely one way journey. For the latter point keep in mind that solar systems are huge. There are enough bodies and resources in our solar system to keep even a spacefaring humanity busy for millions of years. No necessity to travel to the stars for quite a long time. Space is called space for a reason.
misja111 6y ago
If we, here on Earth, want to survive the next couple of centuries we need to find a way to keep our population growth under control. Either we succeed or we most likely will destroy ourselves and/or the Earth. But if we succeed, we also don't have much need to leave Earth anymore. I'd say that this is also the case for other civilisations, which might be another reason why we don't see them.
- gkfasdfasdf 6y ago
  I think we currently have the opposite problem: fertility rates are down, and the world's population is aging. Population growth is slowing and projected to stop. https://www.pewresearch.org/fact-tank/2019/06/17/worlds-population-is-projected-to-nearly-stop-growing-by-the-end-of-the-century/ https://www.pewresearch.org/fact-tank/2019/06/17/worlds-popu...
  - pfdietz 6y ago
    Like pesticides on insects, this will eventually select for people not subject to the birth control effects of modern society.
- D-Coder 6y ago
  This assumes that every single intelligent species fails this way. We only need one that is smart enough or lucky enough to avoid this problem. Similarly for other problems that can block interstellar travel (bureaucracy, nuking themselves, etc).
  - pfdietz 6y ago
    And not just here, but in all the other galaxies we can see. Surveys for K3 civilizations in other galaxies have come up empty.
gkfasdfasdf 6y ago
I think it's about time we started sending probes to other systems. Sure it could take 50-100 years before the probe sent back any meaningful data - but imagine how extraordinary that would be for future generations. Seems like we have the technology for it.
- maxerickson 6y ago
  We don't even have the science for it. https://www.universetoday.com/15403/how-long-would-it-take-to-travel-to-the-nearest-star/ https://www.universetoday.com/15403/how-long-would-it-take-t... And then it would be one of the most significant engineering projects in history.
- rini17 6y ago
  No way. The gravitational lens telescope mission merely >550 AU away is estimated to take 40 years with today's tech.
simonh 6y ago
The article claims since the galaxy is over 13 billion years old there has been that much time for civilisations to emerge and spread. We know that’s not the case. The Universe is only a billion years older than that, and started off as a near homogenous field of hydrogen and helium. All the heavier elements we know today were forged in stars, and distributed when those stars aged and exploded, spewing heavier elements into space. This went through several cycles before reaching the element rich environment we evolved in. It may well be that heavy element densities only reached a viable level in the last generation of stars, maybe the last 1/3 of the history of the universe, or the last 4 to 5 billion years or so. That changes the playing field considerably. Our system might be one of the first capable of supporting life.
- Gravityloss 6y ago
  There's still say a billion year window. The jurassic was 200 million years ago. If some spacefaring civilization developed at that time on some other planet, and the galaxy could be colonized in a few million years, they could have done it a hundred times over since the dinosaurs. The distances in the milky way are mind boggling. But the age of the Earth is even more so.
  - Balgair 6y ago
    As an aside: The technology / evolutionary differences are likely to be immense. Imagine trying to have a 'first contact' with an ant in your backyard. Honestly, for most humans, it's not even close to worth the time or energy to 'talk' with something like that. We don't even consider a single ant worth of much study at all. Now imagine a people as far advanced of us, as that ant is to you. Now imagine that 10,000 times more advanced. Or 100 million times more. That is the kind of difference we have to consider. The unfortunate reality may be that other civilizations are so far advanced from us (100x? 10,000x? 10 billion?) that we are effectively 'alone' all the same. Like an ant pondering the garden hoses, BBQs, or fence posts of the universe.
  - pharke 6y ago
    I think that calculation only works if you replace "colonized" with "explored". Automated, self-replicating probes could reach every star system in the galaxy by moving and spreading as fast as they can but effectively colonizing each system would take a lot longer. This isn't a game of Civilization where you just pump out settlers, real colonists need a reason to leave everything behind and stellar scale civilizations probably take thousands of years to mature and fully exploit their star system. I think the article is closer to the truth.
guscost 6y ago
One of my favorite Christmas traditions is reading these whimsical “how many aliens can dance on a pinhead” arguments that always show up. Have a great holiday break, everyone.
deleted 6y ago
[deleted]
notassigned 6y ago
USS Nimitz UFO incident
rdlecler1 6y ago
It’s not clear why travel would be ‘expensive’. I can imagine a scenario where we create several robots, one for mining, one for chemistry, one for manufacturing, and you could simply send them out start self replicating and creating technology ‘for free’.
fallingfrog 6y ago
On earth, populations move to new regions because of 1) natural population increase and gradual migration by people who are pushed out of their home region due to overcrowding, or 2) deliberate conquest by groups with a very centralized power structure, in which there is a person or group who is in a position to extract tribute or resources from the conquest. In the case of interstellar travel, neither of those two are feasible. The people doing the migrating have to be supported by massive amounts of money, which rules out the first reason for migration, as it’s not a cost efficient way to deal with overpopulation. And there is no way to exert control or exact tribute from light years away, so that rules the second reason for migration. So there is a question of motive: why spend the money when you will not directly benefit?
credit_guy 6y ago
Here's two possible solutions to Fermi's paradox that don't require the Great Filter: interstellar travel is hard, and interstellar communication is hard. 1. Interstellar travel is genuinely hard, so hard that advanced civilizations do it from time to time, but not so often to result in "percolation". In order to have a reasonable argument, let's start from contemplating how hard it would be for us, humans. This is the only civilization we know of at this point. There are two things that make interstellar travel very difficult: 1.a. potential collisions with dust grains and 1.b. violence. 1.a. Danger of collisions. According to wikipedia, cosmic dust grains can have a size up to 500 microns. At a typical density of 2g/cm3 this is a mass of 0.5 mg. Assuming you have a spaceship that travels of 0.01 the speed of light, the energy of impact with such a dust grain will be about 20% the energy of an armor piercing round shot from a modern main battle tank such as the M1 Abrams. Over a 4 light year travel (the distance from us to the closest stars), or a few hundred years of flight at 0.01c, there would be billions- trillions of such impacts. 1.b. Human violence. Assuming we get the technological prowess to accelerate things to 0.01c, what's to stop someone to point a little projectile in the direction of Earth, or some other place colonized by humans? Such of projectile weighing only 15 kg would have the energy of the Hiroshima bomb. In fact, it's actually most likely that the road to interstellar travel will start from military applications, just like the Apollo program was a side-effect of the arms race that created the ICBMs. 2. Interstellar communication is hard. Let's say that aliens are indeed everywhere, including in the planetary systems of our closest galactic neighbors. How would we know? Would SETI find out about that? The only way we'd find out were if they were pointing some large antennas straight at us, and putting some megawatts of power into beaming signals at us. How do we know that? We know because we get radio signals from Voyager 1, which is 150 AU from us. Proxima Centauri is 1700 times further, so the signal would be more than 3 million times weaker. Voyager's antenna is 3.7 meters and the transmitter has 22 W of power. So, if our neighbors are not actively trying to beam signals at us, our chance of detecting them is practically nil.
- pharke 6y ago
  1.a. Invent a better cow catcher 1.b. Space faring civilizations probably don't live on planets the same way we no longer live in caves and mud huts, they build modern houses and cities out in space near to their preferred energy sources and transportation networks. It's a lot harder to hit something smaller and more mobile than a planet and even if you do it doesn't have the same consequences that it would on the ground. i.e. more likely to just punch a big hole rather than convert all its energy to heat, no pressure wave, your neighbours are further away, etc. 2. This is probably why we don't hear anyone, either they are smart about their use of EM communication and everything high powered is directional or they are even smarter than us and have figured out some form of FTL communication.
pharke 6y ago
I think this sounds like a fairly reasonable solution to the paradox. Fermi's Paradox always assumed that at least one civilization would attempt to "colonize" the galaxy as fast as possible but if you think about that logistically it doesn't make much sense. What is the driving motive, cui bono? If we take our own history of colonization as an example, we didn't set out to establish colonies for no reason. We sought out new lands due to a number of reasons, population pressure, lack of opportunity, political oppression, to capitalize on virgin resources such as lumber, gold, and fish. Imagine being an English farmer in 1560, chances are you don't have enough wealth to expand your production even if your neighbours were willing to sell but you would have enough funds if you liquidated your belongings to take a chance on a new world with more land than people. Combine that with the fact that space is big and resources much more plentiful than on a planet alone and it would take a civilization a long time to populate their entire solar system. I don't even think true space faring civilizations would be primarily dependent on planets, once you have enough tonnage in space it would be easier to just build everything in space to begin with rather than trying to drag it out of a gravity well. At that point you have almost infinite real estate since you can just build more land. It wouldn't be a stretch of the imagination to think that a new colony wouldn't be seriously attempted until the current one had formed something akin to a dyson swarm made up of space habitats. The timeline for galactic colonization would have to take this into account. Most of the estimates I've seen assume geometric increase in the number of colonies with the shortest possible dwell time at each star but I think that's an extremely aggressive assumption without any evidence to back it up. I think there are also a large number of confounding variables such as the possibility of civilizational collapse or large scale disaster that may set back colonization efforts.

57 points by headalgorithm 6y ago

Thanks for pointing out this series, here is an rss feed for those interested in never missing the next article: https://www.universetoday.com/feed/?s=%22Beyond+%22Fermi%27s+Paradox%22%22 https://www.universetoday.com/feed/?s=%22Beyond+%22Fermi%27s... Or you can broaden the list with some additional articles tagged as related to the Fermi Paradox with: https://www.universetoday.com/tag/fermi-paradox/feed/ https://www.universetoday.com/tag/fermi-paradox/feed/ It seems the author publishes every few weeks to months.

l33tman 6y ago

It's extremely anthropocentric reasoning, like "the cost is too large", "you lose control of the hegemony" etc. And that there are "colonists" that "die off". I'm not sure any of these assumptions are applicable given billions of possible origins of life at various stages of development. Even at Earth, and with extremely conservative estimates, given 100 more years of nanotech/biotech/AI development, we won't die off, and could certainly send autonomous robot probes. When you don't die anymore, 8 years roundtrip (or more) suddenly doesn't seem so long. BTW in the fiction arena, I suggest reading David Brin "Existence" if you're so inclined which is related to this :)

rm445 6y ago
Great post, but in the context of "Where is everybody?", each 'we won't' or 'we could', where we haven't actually done it yet, is potentially part of the solution to the puzzle. Perhaps filling the universe with undying, exponentially-spreading probes, that don't stop spreading due to values drift, is harder than we think. (Personally, an early filter feels more likely to me, but if it's not that, it's gotta be something).
mabbo 6y ago
> It's extremely anthropocentric reasoning, like "the cost is too large" I'm not sure certain. Cost is, at its core, based on physics- energy, resources and time are the true values all money is based on. Those constraints will exist everywhere in the universe, however they may be treated by an ETI. No matter where you go or who you are, you still need a massive amount of energy to move matter from one star to another.
- l33tman 6y ago
  Travel doesn't cost any energy, only acceleration and decceleration, so if you accept a slow travel this isn't particularly expensive. Especially with drones you wouldn't need a huge spaceship with environmental systems for squishy bio-masses like humans... :)
  - tsimionescu 6y ago
    That's only true if you're launching a piece of rock. Otherwise, it does cost energy to maintain a system running and, at the very least, tracking time for 10000 years. It's not even obvious that it is theoretically possible with current circuit technologies. Pieces would fuse together, moving parts would erode, all sorts of organic materials might deteriorate, everything would be affected by the huge amount of time. And you would almost certainly need energy to actively fight this entropy so that you would have an active machine when you reach your destination.
    - ganzuul 6y ago
      https://en.wikipedia.org/wiki/Magnetic_logic https://en.wikipedia.org/wiki/Magnetic_logic Iron is nuclear ash, and this tech is just about the most reliable implementation of logic we have. It was used in the V2 rocket and US nuclear submarines. It's abandoned tech though and was never pushed beyond 1MHz. If however you have a decade to compute your reactions then that might not matter. Superconducting magnetic loops also store their flux indefinitely, and in space keeping it cool would be trivial.
- TheOtherHobbes 6y ago

imtringued 6y ago

It's pretty obvious. Space is harsh. Even just doing colonization within the solar system is hard to swallow. It's not possible to live on most planets even if we assume that everyone stays in what amounts to a grounded space station. Since we have not yet unlocked fusion we will always have to stay close to the sun. Mars is already too far away. Venus has an extreme atmosphere that causes it to be extremely hot. If a crackpot said we have to build a 100000 person colony in space this century we would have to start on the moon even though there is no water there. The primary reason would be that we are still close enough to the sun that we can use solar panels to generate energy. Space colonization without fusion is simply put: a joke. If space was easy then our galaxy would have been devoured by some grey goo AI (not life) a long time ago. Life has to build artificial habitats and live in them. AIs can just stay in space forever as long as they can gather enough resources.

ben_w 6y ago
I’m more concerned with the politics than the technology of space colonisation. Space colonisation with current tech isn’t a joke, but it is a folly in the sense of British Victorian-era aristocrats — extremely rich people doing fancy but not very cost-effective things. Fusion isn’t necessary for this, however, as PV scales well enough for a Mars colony (don’t get me wrong, still extremal, but it could be made to work up to about Jupiter if cost of local manufacturing was not a limiting factor). But: politics. Let’s assume every settlement on Earth has a corresponding space habitat (O’Neill cylinder or whatever) of the same population in Earth orbit. With this situation, rapid transport between any two locations is trivial enough that high school students could accidentally blow everything up up — I made an ion drive while at school (simple ones are easy) but orbital dynamics are counter-intuitive and not something a high schooler is likely to know, so a kid running one in space with that many large stations around has a high risk of causing a Kessler cascade. Scale the hypothetical scenario up to a K2 swarm around the sun, same applies only with the risk of mass extinction on the home planet. In either case it can be weaponised, and about 19 years ago a bunch of theocratic fundamentalists demonstrated that a small group of humans can be smart enough to cause enormous harm while also being dumb enough to not predict the consequences.
- 6y ago

coldcode 6y ago

One problem with determining how a civilization could travel is we only know what we know now or can reasonably speculate. A hundred years ago we didn't really have the ability to even get into orbit much less imaging visiting another star. Today we can imagine ways but they are insanely expensive and likely to take dozens of years or even centuries at best. Assuming constant progress in technology we might be able to get there faster by waiting decades than by leaving now. Even the absolute limit of light speed, while impossible to imagine today, might turn out to be less of on obstacle in some future understanding of physics. It's hard to predict the future since all you have is today's knowledge.

7373737373 6y ago
https://en.wikipedia.org/wiki/Interstellar_travel#Wait_calculation https://en.wikipedia.org/wiki/Interstellar_travel#Wait_calcu... https://www.researchgate.net/publication/260275150_Interstellar_Travel_-_The_Wait_Calculation_and_the_Incentive_Trap_of_Progress https://www.researchgate.net/publication/260275150_Interstel...
boraoztunc 6y ago
Thinking the same, for travel and all. After 30+ years of my humble existence in this universe, these are the times I want so badly to see a glimpse of the future, a scene from 10.000 years later. SO, SO curious. Thinking is leading me to nowhere with my limited capacity, dreaming with mostly unrelated fantasies and visions. A real one would be nice, even from the exact location I'm sitting now, the street, the sea nearby, everything around, how they evolved. Mind-blowing universe, amazing planet, very little time sadly.
- jdmoreira 6y ago
  10.000 years is a lot. In the past that’s roughly when agriculture was invented. In the future chances are humans will be either extinct or living in very though conditions. The future is not necessarily always better. It certainly wasn’t for the grandsons of hunter-gatherers that became farmers

amelius 6y ago

Why explore space when your holodeck has much better content?

plutonorm 6y ago
I agree. Technology will soon (within 1000 years) take us to a place where whatever we can imagine we can have in a simulation that is indistinguishable from the real world. Why bother with the real world anymore? There maybe some cultures that still see value in the physical world, but I'd wager not many. I also think it's likely that panspermia is a thing. Life is evolving at the galaxy level, it's therefore a little more reasonable to think that we represent one of the more evolutionarily advanced life forms at the current time.
- GoblinSlayer 6y ago
  People who see no value in the physical world don't want simulation to be indistinguishable from the real world.
Enginerrrd 6y ago
Yeah, I actually think there's a ton of merit to this. Fundamentally, the natural progression of technology for any alien species is probably going to be the capability to backup/restore/copy/enhance their consciousness. Biology is delicate, but a purpose-built computer can be designed to survive under very austere conditions, and offers so many incentives! Under the premise that such technology allows for faster and more robust iteration, it would quickly come to dominate the species within which it originates. At that point though, I think there's a lot of incentive toward looking inward rather than outward as an entity--be it from internal competition to become the dominant intelligent entity within your species, or because you've secured a large store of energy and low entropy to harvest. At some point, your iterations are so fast that, IMO, expanding beyond a certain size is likely to introduce a significant fracturing of that society/entity. Why spend the energy on having to compete with your future self?

hliyan 6y ago

When you consider the potential age of the universe [1], we can also argue that the universe is currently in its extreme infancy and we many in fact be one of the very first civilizations to start thinking about other civilizations, and all other "firstborn" civilizations are similarly constrained by technology. [1] https://en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe https://en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe , more dramatically portrayed in this excellent video: A Journey to the End of Time [2] [2] https://youtu.be/uD4izuDMUQA?t=196 https://youtu.be/uD4izuDMUQA?t=196

hindsightbias 6y ago
Evidence points to us having missed all the good parties: https://arxiv.org/abs/2012.07902 https://arxiv.org/abs/2012.07902
pfdietz 6y ago
It has been estimated that 95% of the stars that will ever form have already formed. Far from being in its infancy, from the point of view of locations for new life arising the universe is nearly done. https://scitechdaily.com/star-formation-in-the-universe-has-decreased-drastically/ https://scitechdaily.com/star-formation-in-the-universe-has-...
- soared 6y ago
  But they have existed for a short period of their lifespan, so by definition are early in their lifetimes. The argument isn’t that there will be new stars, but that they will exist for a long time.
  - pfdietz 6y ago
    There's good reason to think life is not going to arise on planets around M stars. Our sun is quite bright compared to the typical star, is already gone through about half its time on the main sequence, and as the Sun continues to brighten the Earth will become uninhabitable in about 1 billion more years. Moreover, life originated early on Earth. This suggests either that more than one extremely rare event is needed to get from life to us, or that the conditions for OoL do not persist for very long (ammonia, for example, is rapidly destroyed by solar radiation.)

GoblinSlayer 6y ago

They assume that a space faring civilization is identical to us down to capitalism, technology, fossil fuel dependency, education, politics, tradition, everything, but this assumption is self defeating: we have all these properties and space travel is infeasible to us, consequently any other civilization that has all the same properties is unable to travel between stars either.

api 6y ago

Interstellar travel is possible with 1960s technology. Search for Project Orion. Thermonuclear Orion could reach as much as 10% the speed of light, which is fast enough to reach the Centauri system in a human life span. Then there is the potential of things like hibernation, or AI that can just turn itself off. The latter would be able to use a less costly but slower propulsion system. I really don’t think travel implausibility works as a Fermi paradox answer. It’s hard but not hard enough to explain the absence of visitors in a galaxy full of planets in habitable zones.

avian 6y ago
> Thermonuclear Orion could reach as much as 10% the speed of light I wonder how much such a mission would cost in terms of total Earth resources. I've read Dyson's book on the project some years back and I don't remember that being mentioned. Wikipedia states the cost in percentage of U.S. GDP (0.1 - 1% of yearly GDP), but I feel like the millions of tons of copper and fissile material required would be significant hit on remaining mineral reserves. It's kind of hard to justify sending out a few missions if it means that the planet left behind is out of easily mined copper and uranium deposits.
- api 6y ago
  It wouldn’t take that much. Fissile material can be bred in fast breeder reactors, and in a thermonuclear Orion type pulse drive most of the power comes from hydrogen fusion. The fissile warheads are primers for each fusion charge. We could probably send a probe to Centauri for the price of one Iraq war. Of course launching “the devil’s pogo stick” from within our biosphere would be rather horrible for the environment. It would be a lot better to build a base on the Moon and launch it from there. You wouldn’t need to burn as much power getting out of a big gravity well. The Moon, being formed from the same stuff as Earth, certainly has fissile material, and it may be closer to the surface and easier to get there. I really think the most likely answer to the Fermi paradox is that extreme intelligence is rare. There probably isn’t a single great filter per se. It’s probably just unlikely for an environment to be simultaneously stable enough over billions of years to produce high intelligence and interesting enough to stimulate its evolution. Most interesting environments will be unstable, and most stable environments uninteresting (a.k.a. having low Shannon information content). The universe is probably full of microbes, simple microbial colonies, and maybe a few worms and bugs, but there are probably not very many minds around capable of harnessing the atom and plotting orbital trajectories. Fewer still may have the motivation to invest in such an epic and likely one way journey. For the latter point keep in mind that solar systems are huge. There are enough bodies and resources in our solar system to keep even a spacefaring humanity busy for millions of years. No necessity to travel to the stars for quite a long time. Space is called space for a reason.

misja111 6y ago

If we, here on Earth, want to survive the next couple of centuries we need to find a way to keep our population growth under control. Either we succeed or we most likely will destroy ourselves and/or the Earth. But if we succeed, we also don't have much need to leave Earth anymore. I'd say that this is also the case for other civilisations, which might be another reason why we don't see them.

gkfasdfasdf 6y ago
I think we currently have the opposite problem: fertility rates are down, and the world's population is aging. Population growth is slowing and projected to stop. https://www.pewresearch.org/fact-tank/2019/06/17/worlds-population-is-projected-to-nearly-stop-growing-by-the-end-of-the-century/ https://www.pewresearch.org/fact-tank/2019/06/17/worlds-popu...
- pfdietz 6y ago
  Like pesticides on insects, this will eventually select for people not subject to the birth control effects of modern society.
D-Coder 6y ago
This assumes that every single intelligent species fails this way. We only need one that is smart enough or lucky enough to avoid this problem. Similarly for other problems that can block interstellar travel (bureaucracy, nuking themselves, etc).
- pfdietz 6y ago
  And not just here, but in all the other galaxies we can see. Surveys for K3 civilizations in other galaxies have come up empty.

gkfasdfasdf 6y ago

I think it's about time we started sending probes to other systems. Sure it could take 50-100 years before the probe sent back any meaningful data - but imagine how extraordinary that would be for future generations. Seems like we have the technology for it.

maxerickson 6y ago
We don't even have the science for it. https://www.universetoday.com/15403/how-long-would-it-take-to-travel-to-the-nearest-star/ https://www.universetoday.com/15403/how-long-would-it-take-t... And then it would be one of the most significant engineering projects in history.
rini17 6y ago
No way. The gravitational lens telescope mission merely >550 AU away is estimated to take 40 years with today's tech.

simonh 6y ago

The article claims since the galaxy is over 13 billion years old there has been that much time for civilisations to emerge and spread. We know that’s not the case. The Universe is only a billion years older than that, and started off as a near homogenous field of hydrogen and helium. All the heavier elements we know today were forged in stars, and distributed when those stars aged and exploded, spewing heavier elements into space. This went through several cycles before reaching the element rich environment we evolved in. It may well be that heavy element densities only reached a viable level in the last generation of stars, maybe the last 1/3 of the history of the universe, or the last 4 to 5 billion years or so. That changes the playing field considerably. Our system might be one of the first capable of supporting life.

Gravityloss 6y ago
There's still say a billion year window. The jurassic was 200 million years ago. If some spacefaring civilization developed at that time on some other planet, and the galaxy could be colonized in a few million years, they could have done it a hundred times over since the dinosaurs. The distances in the milky way are mind boggling. But the age of the Earth is even more so.
- Balgair 6y ago
  As an aside: The technology / evolutionary differences are likely to be immense. Imagine trying to have a 'first contact' with an ant in your backyard. Honestly, for most humans, it's not even close to worth the time or energy to 'talk' with something like that. We don't even consider a single ant worth of much study at all. Now imagine a people as far advanced of us, as that ant is to you. Now imagine that 10,000 times more advanced. Or 100 million times more. That is the kind of difference we have to consider. The unfortunate reality may be that other civilizations are so far advanced from us (100x? 10,000x? 10 billion?) that we are effectively 'alone' all the same. Like an ant pondering the garden hoses, BBQs, or fence posts of the universe.
- pharke 6y ago
  I think that calculation only works if you replace "colonized" with "explored". Automated, self-replicating probes could reach every star system in the galaxy by moving and spreading as fast as they can but effectively colonizing each system would take a lot longer. This isn't a game of Civilization where you just pump out settlers, real colonists need a reason to leave everything behind and stellar scale civilizations probably take thousands of years to mature and fully exploit their star system. I think the article is closer to the truth.

guscost 6y ago

One of my favorite Christmas traditions is reading these whimsical “how many aliens can dance on a pinhead” arguments that always show up. Have a great holiday break, everyone.

deleted 6y ago

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notassigned 6y ago

USS Nimitz UFO incident

rdlecler1 6y ago

It’s not clear why travel would be ‘expensive’. I can imagine a scenario where we create several robots, one for mining, one for chemistry, one for manufacturing, and you could simply send them out start self replicating and creating technology ‘for free’.

fallingfrog 6y ago

On earth, populations move to new regions because of 1) natural population increase and gradual migration by people who are pushed out of their home region due to overcrowding, or 2) deliberate conquest by groups with a very centralized power structure, in which there is a person or group who is in a position to extract tribute or resources from the conquest. In the case of interstellar travel, neither of those two are feasible. The people doing the migrating have to be supported by massive amounts of money, which rules out the first reason for migration, as it’s not a cost efficient way to deal with overpopulation. And there is no way to exert control or exact tribute from light years away, so that rules the second reason for migration. So there is a question of motive: why spend the money when you will not directly benefit?

credit_guy 6y ago

Here's two possible solutions to Fermi's paradox that don't require the Great Filter: interstellar travel is hard, and interstellar communication is hard. 1. Interstellar travel is genuinely hard, so hard that advanced civilizations do it from time to time, but not so often to result in "percolation". In order to have a reasonable argument, let's start from contemplating how hard it would be for us, humans. This is the only civilization we know of at this point. There are two things that make interstellar travel very difficult: 1.a. potential collisions with dust grains and 1.b. violence. 1.a. Danger of collisions. According to wikipedia, cosmic dust grains can have a size up to 500 microns. At a typical density of 2g/cm3 this is a mass of 0.5 mg. Assuming you have a spaceship that travels of 0.01 the speed of light, the energy of impact with such a dust grain will be about 20% the energy of an armor piercing round shot from a modern main battle tank such as the M1 Abrams. Over a 4 light year travel (the distance from us to the closest stars), or a few hundred years of flight at 0.01c, there would be billions- trillions of such impacts. 1.b. Human violence. Assuming we get the technological prowess to accelerate things to 0.01c, what's to stop someone to point a little projectile in the direction of Earth, or some other place colonized by humans? Such of projectile weighing only 15 kg would have the energy of the Hiroshima bomb. In fact, it's actually most likely that the road to interstellar travel will start from military applications, just like the Apollo program was a side-effect of the arms race that created the ICBMs. 2. Interstellar communication is hard. Let's say that aliens are indeed everywhere, including in the planetary systems of our closest galactic neighbors. How would we know? Would SETI find out about that? The only way we'd find out were if they were pointing some large antennas straight at us, and putting some megawatts of power into beaming signals at us. How do we know that? We know because we get radio signals from Voyager 1, which is 150 AU from us. Proxima Centauri is 1700 times further, so the signal would be more than 3 million times weaker. Voyager's antenna is 3.7 meters and the transmitter has 22 W of power. So, if our neighbors are not actively trying to beam signals at us, our chance of detecting them is practically nil.

pharke 6y ago
1.a. Invent a better cow catcher 1.b. Space faring civilizations probably don't live on planets the same way we no longer live in caves and mud huts, they build modern houses and cities out in space near to their preferred energy sources and transportation networks. It's a lot harder to hit something smaller and more mobile than a planet and even if you do it doesn't have the same consequences that it would on the ground. i.e. more likely to just punch a big hole rather than convert all its energy to heat, no pressure wave, your neighbours are further away, etc. 2. This is probably why we don't hear anyone, either they are smart about their use of EM communication and everything high powered is directional or they are even smarter than us and have figured out some form of FTL communication.

pharke 6y ago

I think this sounds like a fairly reasonable solution to the paradox. Fermi's Paradox always assumed that at least one civilization would attempt to "colonize" the galaxy as fast as possible but if you think about that logistically it doesn't make much sense. What is the driving motive, cui bono? If we take our own history of colonization as an example, we didn't set out to establish colonies for no reason. We sought out new lands due to a number of reasons, population pressure, lack of opportunity, political oppression, to capitalize on virgin resources such as lumber, gold, and fish. Imagine being an English farmer in 1560, chances are you don't have enough wealth to expand your production even if your neighbours were willing to sell but you would have enough funds if you liquidated your belongings to take a chance on a new world with more land than people. Combine that with the fact that space is big and resources much more plentiful than on a planet alone and it would take a civilization a long time to populate their entire solar system. I don't even think true space faring civilizations would be primarily dependent on planets, once you have enough tonnage in space it would be easier to just build everything in space to begin with rather than trying to drag it out of a gravity well. At that point you have almost infinite real estate since you can just build more land. It wouldn't be a stretch of the imagination to think that a new colony wouldn't be seriously attempted until the current one had formed something akin to a dyson swarm made up of space habitats. The timeline for galactic colonization would have to take this into account. Most of the estimates I've seen assume geometric increase in the number of colonies with the shortest possible dwell time at each star but I think that's an extremely aggressive assumption without any evidence to back it up. I think there are also a large number of confounding variables such as the possibility of civilizational collapse or large scale disaster that may set back colonization efforts.