If you have a handy black hole around, can you dump the waste heat into a black hole? What that would look like?
More-or-less like a black hole, gravitational signature but no light emitted.
Imagine a scenario where aliens come to a star system, build a Dyson sphere around the star, and then arrange for all that energy to be narrow-beamed to neighbouring star systems where it will be collected and used.
That doesn’t work. The emitted energy must have higher entropy content than the initial energy of the star, so it would be less useful to the destination star. In fact, if the original destination star can extract useful work from it, so could the original star.
so it would be less useful to the destination star.
Sure, but I don’t see a problem here. If you have a particular attachment to a star system, you may want to supply it with energy from other stars instead of moving to them.
The point is that since the energy will get “consumed” elsewhere, the waste heat at the origin will be minimal and so the Dyson sphere will remain relatively cold (though higher than the background temperature, to be sure).
More-or-less like a black hole, gravitational signature but no light emitted.
That doesn’t work. The emitted energy must have higher entropy content than the initial energy of the star, so it would be less useful to the destination star. In fact, if the original destination star can extract useful work from it, so could the original star.
Sure, but I don’t see a problem here. If you have a particular attachment to a star system, you may want to supply it with energy from other stars instead of moving to them.
The point is that since the energy will get “consumed” elsewhere, the waste heat at the origin will be minimal and so the Dyson sphere will remain relatively cold (though higher than the background temperature, to be sure).
However, the destination star would emit large amounts of heat, i.e., infrared.