Yes, remember that the star is still radiating insidethe dyson sphere, so one of fourthings must be happening:
the energy must all be radiated after processing (i.e. after the computer concerned has used the energy to transform its internal data as far as is possible;
or
the dyson sphere (actually a non rigid swarm) would increase in temperature;
or
the swarm could expand in volume due to Boyles Law;
or
the energy could be stored in a non-volatile form such as matter-antimatter pairs (difficult to acheive in practice, AFAIK).
If you look at it that way it is baffling, but if you consider the possibility that the other planets have intelligent life, and may have access to our TV satellites-meaning they’ve seen the reality shows and news networks-they could just be avoiding us. What intelligent lifeform wouldn’t?
eburacum45: Yeah, that’s why I asked about ‘black-body radiation’. I assume a Dyson Sphere would radiate, but not nearly as much as the star inside. Plus, because the Sphere is much, much bigger than the star, the surface temperature would be much lower. So maybe a Dyson sphere would look like a big hole in space, radiating at a low enough temperature to not be easily visible.
If you made it big enough, it would be at the same temperature as the backgroundradiation- but that would be several light minutes across,
iirc.
Anyway, that is one thing the SETI people should be looking for, as well as some kind of powerful anti-asteroid radar which would surely be invaluable for any spacebased society.
Transmissions of data would almost certainly be tight beam laser in visible light or uv (gamma and x-ray lasers seem to have insurmountable problems for data transmission)…
the deep space surveys of extragalactic supernovae could perhaps find some of these bursts of light, although they might not recognise them at first.
OK, um, um, OK, what we’re thinking of as…as aliens, they’re extradimensional beings, that an earlier precursor of the, um, space program made contact with. They are not what they claim to be.