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They only have to be friendly enough to not have to spend the massive amount of resources necessary to travel between solar systems simply to kill off beings yo

They only have to be friendly enough to not have to spend the massive amount of resources necessary to travel between solar systems simply to kill off beings you don't know for no good reason. People seriously underestimate how difficult it would be to travel between solar systems. The scales involved are so far beyond human experience that we can't properly visualize them. Short of discovering a practical FTL (which seems likely to be impossible thanks to the Fermi Paradox) it is unlikely that humans will ever visit a distant solar system.

omoikane 5y ago
They wouldn't simply kill us off, they would raid our resources first, if you believe Stephen Hawking. http://news.bbc.co.uk/2/hi/uk_news/8642558.stm http://news.bbc.co.uk/2/hi/uk_news/8642558.stm
- ncmncm 5y ago
  There is nothing we have that they haven't got, or could get overwhelmingly more easily than getting it from here.
  - danlugo92 5y ago
    Our star is a pretty rare type, what if they want it whole D:.
  - inkblotuniverse 5y ago
    We leave resources unexploited for our own aesthetic or economic reasons- it's uneconomical to mine every ore deposit, and we might not want to, if we value pristine land. Imagine you didn't care about the pristine land- let's ignore aesthetic reasons to hold back for a moment. As technology improves, it becomes easier to exploit resources. You can dig deeper with automated robots etc. Now imagine a technologically mature civilization: one whose tech is pushing the limits of physics. If our current ideas of physics are about right, you have to build things out of matter, and there's a finite amount of matter and negentropy out there. Conversely, right now, replication is cheap. Interstellar travel times are longer than civilisational lifetimes: ergo, most entities that arrive at other stars will have relatively mature technology. If I'm a super-civilisation/large-scale AI digging in for the long haul (till the end of the universe), what do I do? I put out all the stars, if I can, because they're wasteful. Negentropy is finite: we want to eke out every tiny bit of use there, not let hydrogen atoms fuse randomly out of our control. Large corporations viciously purse 0.1% efficiency gains because that amounts to millions of dollars at their scale. At the scale of the galaxy, 0.1% efficiency gains in your conversion of stars, planets, rocks and dust into things you care about is quadrillions of lives. The high travel time means the dynamics are different. You don't have to move from star to star: you can just build (number of solar systems)*(safe number of sentient self-replicating factory probes per system) probes in your home system, and send them out all at once (or as they roll off the line). Every solar system is a massive prize, every star left burning a travesty. If I'm turning the galaxy into stockpiled resources, I'm not going to leave any out that are profitable- and with mature tech, it's all profitable. There's no labor cost, after all.
spookthesunset 5y ago
It’s only impossible under our current understanding of physics, which on the scale of humanity is a brief little slice of time. A hundred years from now who knows what discoveries we will find that either bypass FTL travel or change our understanding of the universe so much that “time and distance” become irrelevant.
gpm 5y ago
I don't think it's necessarily that massive an expenditure. Colonizing another solar system, that's massively expensive. Sending a single interstellar missile at the planet though... that could wipe us out... and definitely seems possible without a huge expenditure of resources (for a civilization with mega-structures). Missiles being much simpler because they don't have to support life, they don't have to slow down - and therefore don't need on board propulsion past what is needed for manoeuvring (assuming some sort of "push it with lasers" style of propulsion), and apart from systems needed for manoeuvring they can really just be a hunk of metal that you accelerate really fast.
- pantalaimon 5y ago
  But what would be their motivation to do so? It would still be a huge effort - and for what? Why destroy a distant civilization?
  - gpm 5y ago
    For humans in a hypothetical advanced society the most likely reason would be preemptive self defence. I think it's a mistake to assume that aliens will be overly similar in their thought process.
    - XorNot 5y ago
      We don't worry too much about killing an ant colony. Which always feels like it should be different when "sentient" beings are involved, but humans are so limited that beyond 150 people we struggle to conceptualize of other sentient minds as "real". So really it could go either way: alien intelligence so advanced and vast that we don't seem meaningfully alive to it, or alien intelligence so advanced and vast that man's inhumanity to man makes us seem impossibly savage and dangerous.
- orlp 5y ago
  Interstellar "rods from god": https://en.wikipedia.org/wiki/Kinetic_bombardment https://en.wikipedia.org/wiki/Kinetic_bombardment A civilization powerful enough to make mega-structures is almost certainly able of landing on one of its endemic large meteors, attach thrusters and over the course of decades accelerate it towards us in a collision path with the earth at a decent fraction of the speed of light. By the time we'd notice it would essentially be impossible to stop.
Georgelemental 5y ago
There are no fundamental physical barriers to sublight generation ships. It would be extremely difficult and expensive, and require lots of new technolgy—unlikely to happen without some supremely compelling motivation. But it's possible.
- addaon 5y ago
  There's also a reasonable chance that the first immortal humans are alive today, depending on how optimistically you project maximum life expectancy curves with medical development. (There's also, of course, an extremely reasonable chance that they're not.) The dynamics of "generation ships" change drastically with changes in human lifetime, including both the dynamics on board such a ship, but also the motivation to pursue it.
  - lazide 5y ago
    Looking at how crazy many folks get being asked to stay at home, I don’t give high odds to a generation ship of awake humans ever making it intact anyway.
    - inkblotuniverse 5y ago
      Don't worry, they'll be overtaken by a 1kg lump of computers, self-replication machinery, and propellant crewed by sapient AI/digitised humans and offered a pickup. Virtual passengers only, though, sorry...
      - lazide 5y ago
        Probably a lot more comfortable for everyone involved too! One can dream, eh?
- ncmncm 5y ago
  Truly, the only thing difficult is getting here in a hurry. Anybody not in a hurry would have little more difficulty than we did launching Voyager or New Horizons. They would, of course, need to build it such that it would operate for long enough to get here, which would be harder. Or, anyway, start operating again once it got near here. It ought not to be very difficult to preserve equipment cooled to 2.7 degrees above absolute zero, which is, notably, below the temperature where helium condenses. Maybe the boiling helium could be used to wake it up.
AdamJacobMuller 5y ago
> for no good reason Why would it need to be a good reason? Especially why would it need to be a good reason, from our perspective? Hardly an original thought but it's entirely possible that an alien civilization pro-forma sends out an unmanned planet-killer-scale weapon at every alien civilization they detect, simply to avoid the possibility that we might grow up to be hostile to them, or even compete with them for resources. An unmanned bomb like that wouldn't take many resources and it's possible they would view us as primitively as we view stomping on an ant hill in africa. Now that's a depressing thought.
- supernovae 5y ago
  Or, they send out probes for science, because only humans have the insatiable appetite for destroying each other.
  - BitwiseFool 5y ago
    >"because only humans have the insatiable appetite for destroying each other." Chimpanzees 'go to war', and so do some non-great ape species like ants and termites. Interestingly, some ant species conquer other colonies and essentially 'enslave' the defeated worker ants using pheromones. It stands to reason that belligerence would arise elsewhere in the universe because it has on Earth several times. https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War
    - sph 5y ago
      Any life on Earth basically is and behaves the same. We're all cousins here. It is unreasonable to assume aliens are anything like us.
      - ALittleLight 5y ago
        When you're sample size is 1 it's wrong to assume that the general population is exactly like your sample. Of course, it's slightly more wrong to assume the general population is nothing like your sample.
317070 5y ago
> It is unlikely that humans will ever visit a distant solar system Yes, but it is quite likely human technology will some day.
- worker_person 5y ago
  But how likely any humans will be in a position to learn the results?
  - pfraze 5y ago
    Depends on your definition of human
chmod775 5y ago
> They only have to be friendly enough to not have to spend the massive amount of resources necessary to travel between solar systems [...] Not many resources really. They can simply use their abundance of energy to hurl, propel, or divert some rock at us at some non-negligible fraction of light speed, and we would be powerless to stop it. Likely we wouldn't even see it coming. Make it two or a dozen to be sure. It doesn't even take a very advanced civilization to pull off such a thing. Give it maybe a hundred years and humanity might be able to do it too. Since it is a rather easy to end a civilization in such a way and it is near impossible to defend against, you arrive at a very... interesting game-theoretic problem: Did they already send kinetic weapons our way? Should we destroy them before they decide to destroy us? If we're about to die anyways, does it even matter if we fire back? It's like the cold war except nobody is able to talk to another and you don't see the nukes coming.
- dorgo 5y ago
  >to hurl, propel, or divert some rock at us at some non-negligible fraction of light speed, and we would be powerless to stop it. Wouldn't you need to solve the n-body problem to hit a planet (earth) from many light years away with a rock? And to do this without exact knowledge of planetary bodies in our star system. And even if you could, a stray hydrogen atom hitting your rock early on would make it miss its target by some light hours. So you better account for every speck of dust on the way and everything with gravitational pull on your rock. An all the quantum fluctuations.. I would even wonder whether the space itself is fine grained enought to precisely target stuff light years away.
  - chmod775 5y ago
    You need to stick the tiny maneuvering thrusters to it in any case. Or maybe just some light sails will do the trick at those distances, depending on how good your aim with the primary means of propulsion was. If humanity was doing this, we'd likely attach propulsion and accelerate the entire way anyways. Unless there's some new drive technology discovered by then or we hijack something natural/environs to do it for us.
manquer 5y ago
> Short of discovering a practical FTL (which seems likely to be impossible thanks to the Fermi Paradox) You could colonize the galaxy in few hundred million years at most without FTL. Replicating machines which can build and launch many more of themselves after reaching each new resource rich system is all that is needed. Humanity may not reach other systems, but either descendants of humanity or human derived machines improved over many generations during transit by AI(doesn’t have to be AGI) is likely to visit.
thedougd 5y ago
Trophy hunting. I've seen the movie.

omoikane 5y ago

They wouldn't simply kill us off, they would raid our resources first, if you believe Stephen Hawking. http://news.bbc.co.uk/2/hi/uk_news/8642558.stm http://news.bbc.co.uk/2/hi/uk_news/8642558.stm

ncmncm 5y ago
There is nothing we have that they haven't got, or could get overwhelmingly more easily than getting it from here.
- danlugo92 5y ago
  Our star is a pretty rare type, what if they want it whole D:.
- inkblotuniverse 5y ago
  We leave resources unexploited for our own aesthetic or economic reasons- it's uneconomical to mine every ore deposit, and we might not want to, if we value pristine land. Imagine you didn't care about the pristine land- let's ignore aesthetic reasons to hold back for a moment. As technology improves, it becomes easier to exploit resources. You can dig deeper with automated robots etc. Now imagine a technologically mature civilization: one whose tech is pushing the limits of physics. If our current ideas of physics are about right, you have to build things out of matter, and there's a finite amount of matter and negentropy out there. Conversely, right now, replication is cheap. Interstellar travel times are longer than civilisational lifetimes: ergo, most entities that arrive at other stars will have relatively mature technology. If I'm a super-civilisation/large-scale AI digging in for the long haul (till the end of the universe), what do I do? I put out all the stars, if I can, because they're wasteful. Negentropy is finite: we want to eke out every tiny bit of use there, not let hydrogen atoms fuse randomly out of our control. Large corporations viciously purse 0.1% efficiency gains because that amounts to millions of dollars at their scale. At the scale of the galaxy, 0.1% efficiency gains in your conversion of stars, planets, rocks and dust into things you care about is quadrillions of lives. The high travel time means the dynamics are different. You don't have to move from star to star: you can just build (number of solar systems)*(safe number of sentient self-replicating factory probes per system) probes in your home system, and send them out all at once (or as they roll off the line). Every solar system is a massive prize, every star left burning a travesty. If I'm turning the galaxy into stockpiled resources, I'm not going to leave any out that are profitable- and with mature tech, it's all profitable. There's no labor cost, after all.

spookthesunset 5y ago

It’s only impossible under our current understanding of physics, which on the scale of humanity is a brief little slice of time. A hundred years from now who knows what discoveries we will find that either bypass FTL travel or change our understanding of the universe so much that “time and distance” become irrelevant.

gpm 5y ago

I don't think it's necessarily that massive an expenditure. Colonizing another solar system, that's massively expensive. Sending a single interstellar missile at the planet though... that could wipe us out... and definitely seems possible without a huge expenditure of resources (for a civilization with mega-structures). Missiles being much simpler because they don't have to support life, they don't have to slow down - and therefore don't need on board propulsion past what is needed for manoeuvring (assuming some sort of "push it with lasers" style of propulsion), and apart from systems needed for manoeuvring they can really just be a hunk of metal that you accelerate really fast.

pantalaimon 5y ago
But what would be their motivation to do so? It would still be a huge effort - and for what? Why destroy a distant civilization?
- gpm 5y ago
  For humans in a hypothetical advanced society the most likely reason would be preemptive self defence. I think it's a mistake to assume that aliens will be overly similar in their thought process.
  - XorNot 5y ago
    We don't worry too much about killing an ant colony. Which always feels like it should be different when "sentient" beings are involved, but humans are so limited that beyond 150 people we struggle to conceptualize of other sentient minds as "real". So really it could go either way: alien intelligence so advanced and vast that we don't seem meaningfully alive to it, or alien intelligence so advanced and vast that man's inhumanity to man makes us seem impossibly savage and dangerous.
orlp 5y ago
Interstellar "rods from god": https://en.wikipedia.org/wiki/Kinetic_bombardment https://en.wikipedia.org/wiki/Kinetic_bombardment A civilization powerful enough to make mega-structures is almost certainly able of landing on one of its endemic large meteors, attach thrusters and over the course of decades accelerate it towards us in a collision path with the earth at a decent fraction of the speed of light. By the time we'd notice it would essentially be impossible to stop.

Georgelemental 5y ago

There are no fundamental physical barriers to sublight generation ships. It would be extremely difficult and expensive, and require lots of new technolgy—unlikely to happen without some supremely compelling motivation. But it's possible.

addaon 5y ago
There's also a reasonable chance that the first immortal humans are alive today, depending on how optimistically you project maximum life expectancy curves with medical development. (There's also, of course, an extremely reasonable chance that they're not.) The dynamics of "generation ships" change drastically with changes in human lifetime, including both the dynamics on board such a ship, but also the motivation to pursue it.
- lazide 5y ago
  Looking at how crazy many folks get being asked to stay at home, I don’t give high odds to a generation ship of awake humans ever making it intact anyway.
  - inkblotuniverse 5y ago
    Don't worry, they'll be overtaken by a 1kg lump of computers, self-replication machinery, and propellant crewed by sapient AI/digitised humans and offered a pickup. Virtual passengers only, though, sorry...
    - lazide 5y ago
      Probably a lot more comfortable for everyone involved too! One can dream, eh?
ncmncm 5y ago
Truly, the only thing difficult is getting here in a hurry. Anybody not in a hurry would have little more difficulty than we did launching Voyager or New Horizons. They would, of course, need to build it such that it would operate for long enough to get here, which would be harder. Or, anyway, start operating again once it got near here. It ought not to be very difficult to preserve equipment cooled to 2.7 degrees above absolute zero, which is, notably, below the temperature where helium condenses. Maybe the boiling helium could be used to wake it up.

AdamJacobMuller 5y ago

> for no good reason Why would it need to be a good reason? Especially why would it need to be a good reason, from our perspective? Hardly an original thought but it's entirely possible that an alien civilization pro-forma sends out an unmanned planet-killer-scale weapon at every alien civilization they detect, simply to avoid the possibility that we might grow up to be hostile to them, or even compete with them for resources. An unmanned bomb like that wouldn't take many resources and it's possible they would view us as primitively as we view stomping on an ant hill in africa. Now that's a depressing thought.

supernovae 5y ago
Or, they send out probes for science, because only humans have the insatiable appetite for destroying each other.
- BitwiseFool 5y ago
  >"because only humans have the insatiable appetite for destroying each other." Chimpanzees 'go to war', and so do some non-great ape species like ants and termites. Interestingly, some ant species conquer other colonies and essentially 'enslave' the defeated worker ants using pheromones. It stands to reason that belligerence would arise elsewhere in the universe because it has on Earth several times. https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War
  - sph 5y ago
    Any life on Earth basically is and behaves the same. We're all cousins here. It is unreasonable to assume aliens are anything like us.
    - ALittleLight 5y ago
      When you're sample size is 1 it's wrong to assume that the general population is exactly like your sample. Of course, it's slightly more wrong to assume the general population is nothing like your sample.

317070 5y ago

> It is unlikely that humans will ever visit a distant solar system Yes, but it is quite likely human technology will some day.

worker_person 5y ago
But how likely any humans will be in a position to learn the results?
- pfraze 5y ago
  Depends on your definition of human

chmod775 5y ago

> They only have to be friendly enough to not have to spend the massive amount of resources necessary to travel between solar systems [...] Not many resources really. They can simply use their abundance of energy to hurl, propel, or divert some rock at us at some non-negligible fraction of light speed, and we would be powerless to stop it. Likely we wouldn't even see it coming. Make it two or a dozen to be sure. It doesn't even take a very advanced civilization to pull off such a thing. Give it maybe a hundred years and humanity might be able to do it too. Since it is a rather easy to end a civilization in such a way and it is near impossible to defend against, you arrive at a very... interesting game-theoretic problem: Did they already send kinetic weapons our way? Should we destroy them before they decide to destroy us? If we're about to die anyways, does it even matter if we fire back? It's like the cold war except nobody is able to talk to another and you don't see the nukes coming.

dorgo 5y ago
>to hurl, propel, or divert some rock at us at some non-negligible fraction of light speed, and we would be powerless to stop it. Wouldn't you need to solve the n-body problem to hit a planet (earth) from many light years away with a rock? And to do this without exact knowledge of planetary bodies in our star system. And even if you could, a stray hydrogen atom hitting your rock early on would make it miss its target by some light hours. So you better account for every speck of dust on the way and everything with gravitational pull on your rock. An all the quantum fluctuations.. I would even wonder whether the space itself is fine grained enought to precisely target stuff light years away.
- chmod775 5y ago
  You need to stick the tiny maneuvering thrusters to it in any case. Or maybe just some light sails will do the trick at those distances, depending on how good your aim with the primary means of propulsion was. If humanity was doing this, we'd likely attach propulsion and accelerate the entire way anyways. Unless there's some new drive technology discovered by then or we hijack something natural/environs to do it for us.

manquer 5y ago

> Short of discovering a practical FTL (which seems likely to be impossible thanks to the Fermi Paradox) You could colonize the galaxy in few hundred million years at most without FTL. Replicating machines which can build and launch many more of themselves after reaching each new resource rich system is all that is needed. Humanity may not reach other systems, but either descendants of humanity or human derived machines improved over many generations during transit by AI(doesn’t have to be AGI) is likely to visit.

thedougd 5y ago

Trophy hunting. I've seen the movie.