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On the other hand, stars are extremely wasteful. A technological civilization will, eventually, encase their sun in an energy extracting Dyson swarm. So why isn

On the other hand, stars are extremely wasteful. A technological civilization will, eventually, encase their sun in an energy extracting Dyson swarm. So why isn't the sky full of dim uniform-distribution infrared blobs?

JauntTrooper 6y ago
Would they still be detectable? Or could they capture enough energy that the stars would be barely noticeable, like trying to find a brown dwarf?
- saberdancer 6y ago
  I followed Tabby's Star news for a while (star that showed massive dips, speculation was that it is a dyson sphere being built). Most scientists believe that even if the star is encased in Dyson sphere that there would be excess infrared emissions as the sphere would need to vent heat. It would be hotter than surrounding space and thus visible. They are thus trying to detect such stars with higher mass and IR excess than expected, but so far there are not many candidates.
- garmaine 6y ago
  You cannot simply absorb all the energy of the star and never emit it. The waste heat has to go somewhere. An efficient Dyson sphere would still emit lower energy infrared radiation in a way that would be detectable from out space-based observatories.
Filligree 6y ago
Because there's no other intelligent life out there. You know that. But it bears mention, for others following along, that rampant artificial intelligence or similar does not count as a great filter candidate, because it would be just as visible as the life it's replacing. That doesn't leave a lot of fast-acting filters that could still be in our future, to be honest. Nuclear war? Sure, but we've avoided it too long for that to be a good one either.
- cgriswald 6y ago
  Artificial intelligence would necessarily have different physical needs than biological life. We can expect even our own AI to be a bit alien to our ways of thinking. Alien created AI would be completely alien to us. With different needs and different motivations, what evidence do we even look for, and if it is pervasive, how do we know we aren’t looking right at it?
  - garmaine 6y ago
    It would still exist in the same universe subject to the same laws of thermodynamics, and would still extract energy from fusion stars in a way that leaves an unmistakable technology signature.
    - cgriswald 6y ago
      It would be subject to the same laws, barring novel physics (like extracting energy from dark matter or some other process we don't yet understand). But a single AI could be smarter than 10 billion humans and consume less energy, need less space, and not care about expanding out into the stars. They could coast around their host star indefinitely and when they eventually needed to leave (which could be never), they could store energy and make a long, slow trek to another star. Imagine trying to find an asteroid-sized object in interstellar space.
- timmytokyo 6y ago
  >Nuclear war? Sure, but we've avoided it too long for that to be a good one either. 75 years is an infinitessimal blip of time in cosmic terms.
rthomas6 6y ago
One must assume either the aliens aren't there, or that the idea is not worth it for reasons we haven't discovered yet. Maybe planetside fusion power is just more efficient. Maybe they can harvest energy from black holes or something.
rtsil 6y ago
Such observation supposes that our timeline matches theirs (taking into account the delay due to lightspeed). We weren't capable of such observation until about a few decades ago, other civilization could have existed and vanished billions of years ago, or billions of years in the future, or are so distant that they're outside of our obserable universe (if they ever was within it). Or energy is not such a big deal anymore once you've reached a certain stage of technological advancement, so it's not the right criteria.
- garmaine 6y ago
  Civilizations won’t go extinct once there are interstellar, thanks to the speed of light balkanizing any such civilization, and thereby providing redundancy.
yesenadam 6y ago
> A technological civilization will, eventually, encase their sun in an energy extracting Dyson swarm. I always wonder, when I read this and similar claims, how on earth the tone of 100% certainty is justified. It seems pure bluff.
- mekkkkkk 6y ago
  I have wondered about this too. I suppose the reasoning is that every solar system has a massive source of energy in the middle of it, and that mega civilizations would be stupid to not utilize it. Sounds probable, but I can see many possible reasons not to bother. Not to mention it is speculating about technology so far ahead of our own that it seems silly. 50's predictions of rocket belts and nuclear powered cars come to mind.
  - TeMPOraL 6y ago
    > 50's predictions of rocket belts and nuclear powered cars come to mind. These are different kind of predictions. Rocket belts could work, but they don't make economic sense and there's a strong safety argument against it. It's the same reason we don't have flying cars either. Nuclear-powered cars could have worked; the failure wasn't predicting technology or its feasibility, but that nobody figured out humanity will collectively go insane and irrationally refuse to develop use of nuclear energy. Dyson spheres are a pretty obvious thing to do - every star is a free, self-maintaining fusion generator that just wastes almost 100% of its output. So the argument is really that when a civilization's need for energy gets larger than what can be supplied by burning whatever stuff they have on their planet, the next obvious step is their star. Barring some magic tech breakthroughs like pulling energy from "subspace" or whatever, you have a rather solid argument that's essentially: "as long as life is not limited from growing, it will eventually start blotting out the sun it orbits".
    - mekkkkkk 6y ago
      The 50s analogy is only to point out how we like to extrapolate contemporary technical understanding into the future. The envisioned dyson spheres I've seen look like our current understanding and use of photovoltaics extrapolated in the same way. I don't disagree that the core idea of harnessing the suns energy seems likely. As the parent poster said, it's just the absolute confidence that people seem to have on the subject that's a bit curious. Maybe breakthroughs in energy generation will make it not worth the effort? Maybe becoming interstellar makes it obsolete since the energy requirements for a given civilization are spread thinner? Maybe there are other ways to harness the solar energy that would not show the same signs as we predict? Maybe civilizations trend to energy efficiency instead of just increased usage? Maybe not.

JauntTrooper 6y ago

Would they still be detectable? Or could they capture enough energy that the stars would be barely noticeable, like trying to find a brown dwarf?

saberdancer 6y ago
I followed Tabby's Star news for a while (star that showed massive dips, speculation was that it is a dyson sphere being built). Most scientists believe that even if the star is encased in Dyson sphere that there would be excess infrared emissions as the sphere would need to vent heat. It would be hotter than surrounding space and thus visible. They are thus trying to detect such stars with higher mass and IR excess than expected, but so far there are not many candidates.
garmaine 6y ago
You cannot simply absorb all the energy of the star and never emit it. The waste heat has to go somewhere. An efficient Dyson sphere would still emit lower energy infrared radiation in a way that would be detectable from out space-based observatories.

Filligree 6y ago

Because there's no other intelligent life out there. You know that. But it bears mention, for others following along, that rampant artificial intelligence or similar does not count as a great filter candidate, because it would be just as visible as the life it's replacing. That doesn't leave a lot of fast-acting filters that could still be in our future, to be honest. Nuclear war? Sure, but we've avoided it too long for that to be a good one either.

cgriswald 6y ago
Artificial intelligence would necessarily have different physical needs than biological life. We can expect even our own AI to be a bit alien to our ways of thinking. Alien created AI would be completely alien to us. With different needs and different motivations, what evidence do we even look for, and if it is pervasive, how do we know we aren’t looking right at it?
- garmaine 6y ago
  It would still exist in the same universe subject to the same laws of thermodynamics, and would still extract energy from fusion stars in a way that leaves an unmistakable technology signature.
  - cgriswald 6y ago
    It would be subject to the same laws, barring novel physics (like extracting energy from dark matter or some other process we don't yet understand). But a single AI could be smarter than 10 billion humans and consume less energy, need less space, and not care about expanding out into the stars. They could coast around their host star indefinitely and when they eventually needed to leave (which could be never), they could store energy and make a long, slow trek to another star. Imagine trying to find an asteroid-sized object in interstellar space.
timmytokyo 6y ago
>Nuclear war? Sure, but we've avoided it too long for that to be a good one either. 75 years is an infinitessimal blip of time in cosmic terms.

rthomas6 6y ago

One must assume either the aliens aren't there, or that the idea is not worth it for reasons we haven't discovered yet. Maybe planetside fusion power is just more efficient. Maybe they can harvest energy from black holes or something.

rtsil 6y ago

Such observation supposes that our timeline matches theirs (taking into account the delay due to lightspeed). We weren't capable of such observation until about a few decades ago, other civilization could have existed and vanished billions of years ago, or billions of years in the future, or are so distant that they're outside of our obserable universe (if they ever was within it). Or energy is not such a big deal anymore once you've reached a certain stage of technological advancement, so it's not the right criteria.

garmaine 6y ago
Civilizations won’t go extinct once there are interstellar, thanks to the speed of light balkanizing any such civilization, and thereby providing redundancy.

yesenadam 6y ago

> A technological civilization will, eventually, encase their sun in an energy extracting Dyson swarm. I always wonder, when I read this and similar claims, how on earth the tone of 100% certainty is justified. It seems pure bluff.

mekkkkkk 6y ago
I have wondered about this too. I suppose the reasoning is that every solar system has a massive source of energy in the middle of it, and that mega civilizations would be stupid to not utilize it. Sounds probable, but I can see many possible reasons not to bother. Not to mention it is speculating about technology so far ahead of our own that it seems silly. 50's predictions of rocket belts and nuclear powered cars come to mind.
- TeMPOraL 6y ago
  > 50's predictions of rocket belts and nuclear powered cars come to mind. These are different kind of predictions. Rocket belts could work, but they don't make economic sense and there's a strong safety argument against it. It's the same reason we don't have flying cars either. Nuclear-powered cars could have worked; the failure wasn't predicting technology or its feasibility, but that nobody figured out humanity will collectively go insane and irrationally refuse to develop use of nuclear energy. Dyson spheres are a pretty obvious thing to do - every star is a free, self-maintaining fusion generator that just wastes almost 100% of its output. So the argument is really that when a civilization's need for energy gets larger than what can be supplied by burning whatever stuff they have on their planet, the next obvious step is their star. Barring some magic tech breakthroughs like pulling energy from "subspace" or whatever, you have a rather solid argument that's essentially: "as long as life is not limited from growing, it will eventually start blotting out the sun it orbits".
  - mekkkkkk 6y ago
    The 50s analogy is only to point out how we like to extrapolate contemporary technical understanding into the future. The envisioned dyson spheres I've seen look like our current understanding and use of photovoltaics extrapolated in the same way. I don't disagree that the core idea of harnessing the suns energy seems likely. As the parent poster said, it's just the absolute confidence that people seem to have on the subject that's a bit curious. Maybe breakthroughs in energy generation will make it not worth the effort? Maybe becoming interstellar makes it obsolete since the energy requirements for a given civilization are spread thinner? Maybe there are other ways to harness the solar energy that would not show the same signs as we predict? Maybe civilizations trend to energy efficiency instead of just increased usage? Maybe not.