4 ms·

Interesting. Just a note: it probably wouldn't seem as if a chunk of the galaxies was removed; in fact, I believe the luminosity (after some settling time) of a

Interesting. Just a note: it probably wouldn't seem as if a chunk of the galaxies was removed; in fact, I believe the luminosity (after some settling time) of a start with a Dyson sphere or the like would emit about the same light a regular star does -- the difference would be the temperature. The apparent temperature of the star should increase(?) (i.e. it emits(?) higher entropy radiation): by simple energy conservation, we wouldn't expect the energy to build up indefinitely inside the sphere. Presumable the energy would be used for computation -- so the end result is that the Star's energy is used to compensate Landauer's Principle[1], essentially cooling the computer. So instead maybe we should look for galaxies that are hotter than expected for their brightness/age? [1] http://en.wikipedia.org/wiki/Landauer%27s_principle http://en.wikipedia.org/wiki/Landauer%27s_principle

marcosdumay 12y ago
Highter entropy radiation has lower temperature. But yes, the energy must go somewhere, thus the total energy irradiated is the same. It just shifts into infrared or radio.
- darkmighty 12y ago
  Oh yea I wasn't sure which one was it! Intuitively it seemed to need to be at lower temperature, but the association of entropy of gases with their temperature made me write otherwise, but of course E=h*f dictates that the entropy from a larger number of lower energy photons must be higher. Thanks for the correction!
danieltillett 12y ago
Such galaxies already exist [1]. They appear to be natural, but who knows for sure. The temperature of the Dyson Sphere will determine the wave length the star apears to shine at. If the sphere is designed to capture the maximum energy possible then the temperature will be close to the cosmic background radiation temperature (2.73K) and so would be very hard to detect. 1. http://en.m.wikipedia.org/wiki/Luminous_infrared_galaxy http://en.m.wikipedia.org/wiki/Luminous_infrared_galaxy

marcosdumay 12y ago

Highter entropy radiation has lower temperature. But yes, the energy must go somewhere, thus the total energy irradiated is the same. It just shifts into infrared or radio.

darkmighty 12y ago
Oh yea I wasn't sure which one was it! Intuitively it seemed to need to be at lower temperature, but the association of entropy of gases with their temperature made me write otherwise, but of course E=h*f dictates that the entropy from a larger number of lower energy photons must be higher. Thanks for the correction!

danieltillett 12y ago

Such galaxies already exist [1]. They appear to be natural, but who knows for sure. The temperature of the Dyson Sphere will determine the wave length the star apears to shine at. If the sphere is designed to capture the maximum energy possible then the temperature will be close to the cosmic background radiation temperature (2.73K) and so would be very hard to detect. 1. http://en.m.wikipedia.org/wiki/Luminous_infrared_galaxy http://en.m.wikipedia.org/wiki/Luminous_infrared_galaxy