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>Every other society realized it at the same time? Which would imply every other society is roughly born at the same time, which sounds unlikely. So some of the

>Every other society realized it at the same time? Which would imply every other society is roughly born at the same time, which sounds unlikely. So some of them (like us) should not yet have discovered the danger of broadcasting signals. And I'll play Devil's Advocate to your Devil's Advocate. :) It's entirely possible that there have been other technological civilizations over the past 13.7 or so billion years. That's a long time. As such, any civilization that stopped broadcasting in our direction, if they ever did so in the first place, any more than 100,000 or so years ago, would be completely undetectable to us -- ever. What's more, as was pointed out in another comment, we haven't been looking for such signals for long (~60 years) and haven't surveyed anything close to the entire galaxy. I guess the most accurate thing we can say would be that we haven't detected another technological civilization within 60 light years or so in the few places we've looked. Given the lack of data, the Drake equation[0] is less a predictive device than a way to categorize our ignorance. The Fermi Paradox[1] and its "where is everybody?" question is more in line with what I perceive to be your point. Given that we haven't looked very hard for very long (as I mention above) in an enormous galaxy that's existed for billions of years, it seems to be in a similar position as any predictions from the Drake equation. It's interesting to speculate, but without enough data, speculation is all it is. [0] https://en.wikipedia.org/wiki/Drake_equation https://en.wikipedia.org/wiki/Drake_equation [1] https://en.wikipedia.org/wiki/Fermi_paradox https://en.wikipedia.org/wiki/Fermi_paradox

krapp 6y ago
>Given that we haven't looked very hard for very long (as I mention above) in an enormous galaxy that's existed for billions of years, it seems to be in a similar position as any predictions from the Drake equation. Also remember the search space isn't even just a single galaxy, it's the entire observable universe with a hundred billion galaxies, give or take.
Voloskaya 6y ago
> It's entirely possible that there have been other technological civilizations over the past 13.7 or so billion years. That's a long time. As such, any civilization that stopped broadcasting in our direction, if they ever did so in the first place, any more than 100,000 or so years ago, would be completely undetectable to us -- ever. But this is assuming radio signals are the only way we could detect a civilization, what about probes (von neuman or regular), dyson spheres etc. ? > I guess the most accurate thing we can say would be that we haven't detected another technological civilization within 60 light years or so in the few places we've looked The signals we received in the last 60 years come from the entire observable universe (it's how we define the observable universe), not just from a 60 ly radius. But the furthest the signal comes from the hardest it is to detect (or the strongest it would have to be to be detectable). > It's interesting to speculate, but without enough data, speculation is all it is. I certainly hope that everyone is aware that is pure speculation ;)
- fiblye 6y ago
  > But this is assuming radio signals are the only way we could detect a civilization, what about probes (von neuman or regular), dyson spheres etc. ? That’s trying to find a needle in a universe sized haystack, and we’ve only just started digging. Concluding that there’s probably not a needle when we’ve only just started digging our hands in is premature.
  - Voloskaya 6y ago
    > That’s trying to find a needle in a universe sized haystack But that is the whole point of the fermi paradox. Given the staggering numbers of planets in our galaxy/universe, and given the staggering age of the universe (when compared to our history), it should not be like trying to find a needle in a haystack. If it is, then that means life is extremly rare, which already answers part of the question.
    - halfdan 6y ago
      Even if it's as rare as one in a billion we'd still have to map billions of suns, their planets and actually look for it. Other than SETI I don't know any really serious, concerted efforts to looks for other signals of life. Even the discovery here was somewhat random and required someone to start digging through recorded data.
    - fiblye 6y ago
      That comes with the big assumption that in basically any given corner of the universe, civilizations in galaxies billions of light years away are pumping out radio signals strong enough to be detected from earth. How likely is it that by the time humanity would be a space faring society that we’d be pumping turbo charged radio signals that are easily distinguished from noise when doing a quick sweep? How likely is it that societies are using radio signals or something similar for a long period of time, and not simply using some better method that humans have yet to discover?
      - Voloskaya 6y ago

krapp 6y ago

>Given that we haven't looked very hard for very long (as I mention above) in an enormous galaxy that's existed for billions of years, it seems to be in a similar position as any predictions from the Drake equation. Also remember the search space isn't even just a single galaxy, it's the entire observable universe with a hundred billion galaxies, give or take.

Voloskaya 6y ago

> It's entirely possible that there have been other technological civilizations over the past 13.7 or so billion years. That's a long time. As such, any civilization that stopped broadcasting in our direction, if they ever did so in the first place, any more than 100,000 or so years ago, would be completely undetectable to us -- ever. But this is assuming radio signals are the only way we could detect a civilization, what about probes (von neuman or regular), dyson spheres etc. ? > I guess the most accurate thing we can say would be that we haven't detected another technological civilization within 60 light years or so in the few places we've looked The signals we received in the last 60 years come from the entire observable universe (it's how we define the observable universe), not just from a 60 ly radius. But the furthest the signal comes from the hardest it is to detect (or the strongest it would have to be to be detectable). > It's interesting to speculate, but without enough data, speculation is all it is. I certainly hope that everyone is aware that is pure speculation ;)

fiblye 6y ago
> But this is assuming radio signals are the only way we could detect a civilization, what about probes (von neuman or regular), dyson spheres etc. ? That’s trying to find a needle in a universe sized haystack, and we’ve only just started digging. Concluding that there’s probably not a needle when we’ve only just started digging our hands in is premature.
- Voloskaya 6y ago
  > That’s trying to find a needle in a universe sized haystack But that is the whole point of the fermi paradox. Given the staggering numbers of planets in our galaxy/universe, and given the staggering age of the universe (when compared to our history), it should not be like trying to find a needle in a haystack. If it is, then that means life is extremly rare, which already answers part of the question.
  - halfdan 6y ago
    Even if it's as rare as one in a billion we'd still have to map billions of suns, their planets and actually look for it. Other than SETI I don't know any really serious, concerted efforts to looks for other signals of life. Even the discovery here was somewhat random and required someone to start digging through recorded data.
  - fiblye 6y ago
    That comes with the big assumption that in basically any given corner of the universe, civilizations in galaxies billions of light years away are pumping out radio signals strong enough to be detected from earth. How likely is it that by the time humanity would be a space faring society that we’d be pumping turbo charged radio signals that are easily distinguished from noise when doing a quick sweep? How likely is it that societies are using radio signals or something similar for a long period of time, and not simply using some better method that humans have yet to discover?
    - Voloskaya 6y ago