5 ms·

If you look at the realistic reach of the signals of human civilization, it's a few tens of lightyears at best. And once you factor in how inhumane it'd be to

If you look at the realistic reach of the signals of human civilization, it's a few tens of lightyears at best. And once you factor in how inhumane it'd be to send children out to colonize foreign solar systems ... are we really sure we'll do that? That's 10 generations that live their entire lives in small metal boxes ... without the vast majority of everything we have on earth. Not so much as a single field of grass (or field of anything, building a big room in space will be a great challenge, especially since weightlessness means you don't really need room). 10 generations that will have absolutely zero power to do anything about their situation. It will take 100+ generations before anything remotely resembling earth level comfort will happen (assuming the planets encountered can at any point support human life. If they need to be terraformed, we're easily talking 1000+ generations)

dogma1138 5y ago
That’s an accurate statement the reality is that any civilization that develops sufficient level of technology to allow it to spread across a single galaxy or even to adjacent star systems would be able to use that technology to find better alternatives in their own star system. That’s if civilizations even live that long in the first place.
- Ekaros 5y ago
  Minimal fraction of suns energy output would allow insane number of humans to survive. And it will be around a while so there is really no hurry to move out. Kinda comes to calculation that when earliest potentially space faring civilisation runs out of their sun? And can't adapt to live in system. For us that would still be at least few billions of years if not more with proper preparation.
  - Nbox9 5y ago
    I could imagine humans fighting over the limited energy harvested by Sol’s Dyson sphere in 10million years. It would give any group of human’s controlling it a massive advantage, similarly to the advantage having the only A-bomb gave US briefly.
    - Ekaros 5y ago
      On the other end, looking at the population growth projections there might not be too many humans to fight over it in 10 million years. Who am I kidding, they would still fight over it...
    - rsynnott 5y ago
      That's assuming that people have an inexhaustible appetite for energy, geometric population expansion, or both. Those are both actually quite big assumptions and aren't supported by current trends.
    - SubiculumCode 5y ago
      Maybe. Just maybe. We will have artificial fusion energy in 10M years. ;)
      - Nbox9 5y ago
        Even if we had fusion most of the mass in the solar system exists in the sun, so that’s where most of the energy is. E=mc^2.
    - giantrobot 5y ago
      There is an absolutely stupid amount of energy given off by the Sun. We're finally waking up to the fact we can capture a portion of the small portion that hits Earth every second to power our civilization. Higher technology levels have only increased the efficiency of our power use and use per capita. I'm not saying we're at the height of technology or development or anything but the idea we'd need a whole star's worth of power output for something I think is ludicrous. If you've got the technology to build a Dyson sphere (or swarm) it's unlikely you'd actually need to. To even get to that point as a tool-using civilization you couldn't have had unchecked geometric growth. Unless you had some Motie-like biological imperative to reproduce uncontrollably your civilization would reach a point long before Dyson sphere level where it worked fine without having to move the mass of several solar systems around a star to capture some high fraction of its power output.
Nbox9 5y ago
I’m unsure the human rights aspect is going to be the limiting factor. Humans are constantly doing inhuman things. We have a history of forcibly migrating people, it’s not uncommon in our history at all. I think it’s just as likely that we never spend the engineering effort on a multi-generation colonization ship. Compared to inner-stellar travel inter-stellar travel requires much much more space, robust systems, and reliability. For example, the distance between Earth and the nearest star is over 100,000,000 times the distance between Earth and Jupiter. It’s questionable we’ll ever put the effort into being inner-stellar, but the difference between inner-stellar and inter-stellar is greater than the difference between a paddle board and an aircraft carrier.
- ido 5y ago
  Assume we survive climate change as a technologically advanced society & that no other natural disaster or war wipe us out, so you really think you can predict what sort of technology will or will not be available to humans 1,000 years from now? How about 1,000,000? If in those time spans we figure out a way to sustain 1g acceleration throughout the trip (currently not achievable but less sci-fi than FTL) we can reach nearby stars within the lifetime of the astronauts: https://www.forbes.com/sites/startswithabang/2021/12/30/how-far-could-a-spaceship-go-if-we-never-ran-out-of-thrust/ https://www.forbes.com/sites/startswithabang/2021/12/30/how-...
  - Nbox9 5y ago
    In your favor “How can we go faster” has been a question people have been asking for thousands of years, and we’ve made pretty steady progress on it.
kypro 5y ago
But why would a sufficiently advanced civilisation choose to colonise the galaxy with organic human-like beings? Surely it would make far more sense for this hypothetical civilisation to send robots first? A technologically advanced civilisation is also likely to rebuild their organic bodies specifically to overcome these limitations, in which case concerns around terraforming really aren't that big a deal. The problems you're raising are far more technological in nature than fundamental IMO. I agree that as it stands it wouldn't make much sense to attempt to colonise the galaxy even if we had the rocket technology today, but by the end of the century we'll probably have the kind of technology required to colonise the galaxy (robots, AI, improved battery tech) even if we're still stuck with slow combustion rockets.
- nexuist 5y ago
  This adds a new, unexpected element to the alien visitation theory: the aliens that come here will not be alive at all, they will be robots programmed to extract resources that cannot be reasoned with diplomatically (assuming they are not outfitted with general intelligence). Unless the senders thought ahead and built empathy into the robots, there will be no way to end the invasion other than to kill everything that comes here.
  - baja_blast 5y ago
    There are no resources on Earth that a space fairing civilization or robot would need that they couldn't get far more practically from asteroids. Earth is a gravity well, extracting resources from the planet and getting it off is way harder than just mining Kuiper belt, lots of water, minerals, metals anything they would need.
    - bluGill 5y ago
      One exception to that: gravity. The only reason I can think of they would want our gravity is if they want to live here though, so we are back to them not sending robots which we already agreed isn't likely.
rsynnott 5y ago
> If you look at the realistic reach of the signals of human civilization, it's a few tens of lightyears at best. And probably getting smaller every year. We don't have as many giant multi-megawatt radio transmitters as we used to. Quite conceivably it could be ~zero in a few decades, as everything goes fibre and cellular.
- giantrobot 5y ago
  Even our multi-megawatt transmitters being detectable for tens of light years is largely a myth. Omnidirectional broadcasts need to be powerful just to be detected several miles away thanks to the inverse square law. Most powerful TV and radio transmitters won't be detectable too far outside the solar system. It takes a lot of power (or a highly directional antenna) to send a detectable signal detectable light years away. The only unintentional signals we generate are high power weather and military radar. Those are very tight beams that sweep the sky. Any interstellar eavesdropper would need to have the beam sweep over them to detect it. Even then it would be a transient signal with no guarantee of repetition since everything is it motion. It would be like us being a mile apart in the blackest of night and you swinging a laser pointer around. Even if I'm looking specifically for you and have a general idea where you are the odds are vanishingly small your laser pointer will happen to be visible to me. You'd have to be specifically pointing it at me to even have a hope of me seeing it.
- Ekaros 5y ago
  And they stop being trivial to decode like AM or FM was. How we reach those higher speeds makes whole thing much harder to get anything out of.

dogma1138 5y ago

That’s an accurate statement the reality is that any civilization that develops sufficient level of technology to allow it to spread across a single galaxy or even to adjacent star systems would be able to use that technology to find better alternatives in their own star system. That’s if civilizations even live that long in the first place.

Ekaros 5y ago
Minimal fraction of suns energy output would allow insane number of humans to survive. And it will be around a while so there is really no hurry to move out. Kinda comes to calculation that when earliest potentially space faring civilisation runs out of their sun? And can't adapt to live in system. For us that would still be at least few billions of years if not more with proper preparation.
- Nbox9 5y ago
  I could imagine humans fighting over the limited energy harvested by Sol’s Dyson sphere in 10million years. It would give any group of human’s controlling it a massive advantage, similarly to the advantage having the only A-bomb gave US briefly.
  - Ekaros 5y ago
    On the other end, looking at the population growth projections there might not be too many humans to fight over it in 10 million years. Who am I kidding, they would still fight over it...
  - rsynnott 5y ago
    That's assuming that people have an inexhaustible appetite for energy, geometric population expansion, or both. Those are both actually quite big assumptions and aren't supported by current trends.
  - SubiculumCode 5y ago
    Maybe. Just maybe. We will have artificial fusion energy in 10M years. ;)
    - Nbox9 5y ago
      Even if we had fusion most of the mass in the solar system exists in the sun, so that’s where most of the energy is. E=mc^2.
  - giantrobot 5y ago
    There is an absolutely stupid amount of energy given off by the Sun. We're finally waking up to the fact we can capture a portion of the small portion that hits Earth every second to power our civilization. Higher technology levels have only increased the efficiency of our power use and use per capita. I'm not saying we're at the height of technology or development or anything but the idea we'd need a whole star's worth of power output for something I think is ludicrous. If you've got the technology to build a Dyson sphere (or swarm) it's unlikely you'd actually need to. To even get to that point as a tool-using civilization you couldn't have had unchecked geometric growth. Unless you had some Motie-like biological imperative to reproduce uncontrollably your civilization would reach a point long before Dyson sphere level where it worked fine without having to move the mass of several solar systems around a star to capture some high fraction of its power output.

Nbox9 5y ago

I’m unsure the human rights aspect is going to be the limiting factor. Humans are constantly doing inhuman things. We have a history of forcibly migrating people, it’s not uncommon in our history at all. I think it’s just as likely that we never spend the engineering effort on a multi-generation colonization ship. Compared to inner-stellar travel inter-stellar travel requires much much more space, robust systems, and reliability. For example, the distance between Earth and the nearest star is over 100,000,000 times the distance between Earth and Jupiter. It’s questionable we’ll ever put the effort into being inner-stellar, but the difference between inner-stellar and inter-stellar is greater than the difference between a paddle board and an aircraft carrier.

ido 5y ago
Assume we survive climate change as a technologically advanced society & that no other natural disaster or war wipe us out, so you really think you can predict what sort of technology will or will not be available to humans 1,000 years from now? How about 1,000,000? If in those time spans we figure out a way to sustain 1g acceleration throughout the trip (currently not achievable but less sci-fi than FTL) we can reach nearby stars within the lifetime of the astronauts: https://www.forbes.com/sites/startswithabang/2021/12/30/how-far-could-a-spaceship-go-if-we-never-ran-out-of-thrust/ https://www.forbes.com/sites/startswithabang/2021/12/30/how-...
- Nbox9 5y ago
  In your favor “How can we go faster” has been a question people have been asking for thousands of years, and we’ve made pretty steady progress on it.

kypro 5y ago

But why would a sufficiently advanced civilisation choose to colonise the galaxy with organic human-like beings? Surely it would make far more sense for this hypothetical civilisation to send robots first? A technologically advanced civilisation is also likely to rebuild their organic bodies specifically to overcome these limitations, in which case concerns around terraforming really aren't that big a deal. The problems you're raising are far more technological in nature than fundamental IMO. I agree that as it stands it wouldn't make much sense to attempt to colonise the galaxy even if we had the rocket technology today, but by the end of the century we'll probably have the kind of technology required to colonise the galaxy (robots, AI, improved battery tech) even if we're still stuck with slow combustion rockets.

nexuist 5y ago
This adds a new, unexpected element to the alien visitation theory: the aliens that come here will not be alive at all, they will be robots programmed to extract resources that cannot be reasoned with diplomatically (assuming they are not outfitted with general intelligence). Unless the senders thought ahead and built empathy into the robots, there will be no way to end the invasion other than to kill everything that comes here.
- baja_blast 5y ago
  There are no resources on Earth that a space fairing civilization or robot would need that they couldn't get far more practically from asteroids. Earth is a gravity well, extracting resources from the planet and getting it off is way harder than just mining Kuiper belt, lots of water, minerals, metals anything they would need.
  - bluGill 5y ago
    One exception to that: gravity. The only reason I can think of they would want our gravity is if they want to live here though, so we are back to them not sending robots which we already agreed isn't likely.

rsynnott 5y ago

> If you look at the realistic reach of the signals of human civilization, it's a few tens of lightyears at best. And probably getting smaller every year. We don't have as many giant multi-megawatt radio transmitters as we used to. Quite conceivably it could be ~zero in a few decades, as everything goes fibre and cellular.

giantrobot 5y ago
Even our multi-megawatt transmitters being detectable for tens of light years is largely a myth. Omnidirectional broadcasts need to be powerful just to be detected several miles away thanks to the inverse square law. Most powerful TV and radio transmitters won't be detectable too far outside the solar system. It takes a lot of power (or a highly directional antenna) to send a detectable signal detectable light years away. The only unintentional signals we generate are high power weather and military radar. Those are very tight beams that sweep the sky. Any interstellar eavesdropper would need to have the beam sweep over them to detect it. Even then it would be a transient signal with no guarantee of repetition since everything is it motion. It would be like us being a mile apart in the blackest of night and you swinging a laser pointer around. Even if I'm looking specifically for you and have a general idea where you are the odds are vanishingly small your laser pointer will happen to be visible to me. You'd have to be specifically pointing it at me to even have a hope of me seeing it.
Ekaros 5y ago
And they stop being trivial to decode like AM or FM was. How we reach those higher speeds makes whole thing much harder to get anything out of.