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Is it possible that the gravitational discrepancies can be explained with dyson spheres? Or dyson spheres collected into grids (with a dyson sphere scale tech

Is it possible that the gravitational discrepancies can be explained with dyson spheres? Or dyson spheres collected into grids (with a dyson sphere scale tech you can prob move suns by making the dyson sphere a giant fusion engine). There is an advantage to arranging dyson spheres closer together in order to reduce latency between nodes. If your dyson spheres were optimized enough, could absorb all known spectrums and recycle them. Wouldn’t that appear completely dark save for gravity? I mean, isn’t it possible entire galaxies have been converted in this way? Seems like it could be a much simpler explanation within the confines of current understanding. But I’m sure this has been thought about and accounted for.

badpun 4y ago
My layman understanding is that the dyson spheres would occlude objects behind them if they happen to be in line of sight to us. Given that things in the universe are not static, other (visible) bodies would move in and out of occlusion, allowing us to detect the DS.
- gbasin 4y ago
  Nothing an LCD and some cameras can't solve
  - badpun 4y ago
    Only if they would want to fool us specifically. Those LCDs would have to display a different image for every different point of view, so they can choose only one planet in the universe to fool.
    - geysersam 4y ago
      And they chose us. Just our luck!
growt 4y ago
Sure, but occams razor would probably prefer some gas cloud.
krastanov 4y ago
> If your dyson spheres were optimized enough, could absorb all known spectrums and recycle them. A really cool outcome of statistical mechanics and thermodynamics is that what you suggest is impossible. The dyson sphere can be as amazing as you want, using every single trickery permitted by physics, but at some point it will enter thermal equilibrium with its host start (or pipe that heat somewhere else where you would still be able to see its thermal radiation). Inherently, if they are optimized to be good absorbers, they will have to also be thermal emitters. There is no such thing as "recycle all spectrum". Tangentially related to the fact that a "perfectly black body", i.e. a perfect absorber, is also the perfect emitter of thermal radiation of its own.
- tiagod 4y ago
  Couldn't it be a good emitter, but redirect the heat in a focused way? (beam of RF)
  - OkayPhysicist 4y ago
    Nope. That would violate the 2nd Law of Thermodynamics.
    - survirtual 4y ago
      Why? Couldn’t one build a dyson sphere around a blackhole? Wouldn’t the blackhole have properties of a Bose–Einstein condensate given the matter at the center cannot vibrate? It would be the coldest temperature possible. Heat moves downhill, you deposit heat into a singularity and have a shell around it. That aside, at even a scale of a single dyson sphere, something tells me when a civilization has the power to bend spacetime, the rules of possibilities begin to change. I think it is unwise to operate with so much certainty in the face of possibilities.
  - krastanov 4y ago
    The sibling already mentioned the axioms of thermodynamics that forbid it. Another way to see that this is forbidden is Etendue https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendue https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendu...
gus_massa 4y ago
It's very similar to artificial MACHOs. The natural version uses neutron starts and other difficult to detect big natural things instead of Dyson spheres. https://en.wikipedia.org/wiki/Massive_compact_halo_object https://en.wikipedia.org/wiki/Massive_compact_halo_object
fallingknife 4y ago
For this to match observations, all galaxies visible outside the milky way would have to be Dyson sphered through their whole extent. If they weren't, it would be obviously visible, as an expanding civilization that had only spread throughout half a galaxy would be a totally lopsided galaxy. And for some reason, all of those civilizations must have decided to leave a certain percentage of stars un-sphered even though they have the capacity to sphere them all. And the Milky way would have to be un-dyson sphered, because if it were, we would be able to notice these spheres close up. e.g. if dark matter is 5x regular matter, we would expect there to be 5 Dyson spheres of stars the size of the alpha centauri system all within 4ly of Earth. This would be easy to detect through occlusion. Also, gravitational interactions between sphered stars and unsphered stars would be easily observable in our own galaxy. So for this to work, at minimum, the whole observable universe must by Dyson sphered, except for our own galaxy.

badpun 4y ago

My layman understanding is that the dyson spheres would occlude objects behind them if they happen to be in line of sight to us. Given that things in the universe are not static, other (visible) bodies would move in and out of occlusion, allowing us to detect the DS.

gbasin 4y ago
Nothing an LCD and some cameras can't solve
- badpun 4y ago
  Only if they would want to fool us specifically. Those LCDs would have to display a different image for every different point of view, so they can choose only one planet in the universe to fool.
  - geysersam 4y ago
    And they chose us. Just our luck!

growt 4y ago

Sure, but occams razor would probably prefer some gas cloud.

krastanov 4y ago

> If your dyson spheres were optimized enough, could absorb all known spectrums and recycle them. A really cool outcome of statistical mechanics and thermodynamics is that what you suggest is impossible. The dyson sphere can be as amazing as you want, using every single trickery permitted by physics, but at some point it will enter thermal equilibrium with its host start (or pipe that heat somewhere else where you would still be able to see its thermal radiation). Inherently, if they are optimized to be good absorbers, they will have to also be thermal emitters. There is no such thing as "recycle all spectrum". Tangentially related to the fact that a "perfectly black body", i.e. a perfect absorber, is also the perfect emitter of thermal radiation of its own.

tiagod 4y ago
Couldn't it be a good emitter, but redirect the heat in a focused way? (beam of RF)
- OkayPhysicist 4y ago
  Nope. That would violate the 2nd Law of Thermodynamics.
  - survirtual 4y ago
    Why? Couldn’t one build a dyson sphere around a blackhole? Wouldn’t the blackhole have properties of a Bose–Einstein condensate given the matter at the center cannot vibrate? It would be the coldest temperature possible. Heat moves downhill, you deposit heat into a singularity and have a shell around it. That aside, at even a scale of a single dyson sphere, something tells me when a civilization has the power to bend spacetime, the rules of possibilities begin to change. I think it is unwise to operate with so much certainty in the face of possibilities.
- krastanov 4y ago
  The sibling already mentioned the axioms of thermodynamics that forbid it. Another way to see that this is forbidden is Etendue https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendue https://en.wikipedia.org/wiki/Etendue#Conservation_of_etendu...

gus_massa 4y ago

It's very similar to artificial MACHOs. The natural version uses neutron starts and other difficult to detect big natural things instead of Dyson spheres. https://en.wikipedia.org/wiki/Massive_compact_halo_object https://en.wikipedia.org/wiki/Massive_compact_halo_object

fallingknife 4y ago

For this to match observations, all galaxies visible outside the milky way would have to be Dyson sphered through their whole extent. If they weren't, it would be obviously visible, as an expanding civilization that had only spread throughout half a galaxy would be a totally lopsided galaxy. And for some reason, all of those civilizations must have decided to leave a certain percentage of stars un-sphered even though they have the capacity to sphere them all. And the Milky way would have to be un-dyson sphered, because if it were, we would be able to notice these spheres close up. e.g. if dark matter is 5x regular matter, we would expect there to be 5 Dyson spheres of stars the size of the alpha centauri system all within 4ly of Earth. This would be easy to detect through occlusion. Also, gravitational interactions between sphered stars and unsphered stars would be easily observable in our own galaxy. So for this to work, at minimum, the whole observable universe must by Dyson sphered, except for our own galaxy.