Dyson sphere around the black hole
Tiger Yu-Yang Hsiao1*, Tomotsugu Goto1
1Institute of Astronomy, National Tsing Hua University, Hsinchu, Taiwan
* Presenter:Tiger Yu-Yang Hsiao, email:tigerhsiao@gapp.nthu.edu.tw
The search for extra-terrestrial intelligence (SETI) has been conducted for 60 years. Although hitherto there is only negative result, individuals’ curiosities have been invoked. We assume a civilization which develops the technology between Type II and Type III civilization (the Alien) in the universe. The Alien must have collected the energy from their parent star for a while and start to absorb or start absorbing the energy from the nearby stars. In this study, we discuss and conclude that the collectable energy from cosmic wave background (CMB) and Hawking radiation would be too small to maintain the civilization regardless of present or future. Nevertheless, if the Alien has the technology advanced enough to afford the strong radiation from accretion disk and the relativistic jests, they can absorb a large amount of energy compared to a similar size star in the main sequence even if the efficiency is low. Considering the spectra, our results show that Dyson sphere is measurable in the UV, optical and IR wavelengths due to the radiation of waste heat.

Keywords: black holes, Dyson sphere, SETI