One possible solution is dyson ball – a kind of massive stellar engineering project that encapsulates an entire star (or, in this case, a
“> Dungeon) in an artificial envelope that captures all the energy emitted by the body at its center. But even if it were able to capture all the energy the black hole emits, the ball itself would still suffer heat loss. And that this heat loss will make it visible to us, according to new research published by an international team led by researchers from National Tsing Hua University in Taiwan.
Obviously, such a structure has not yet been discovered. However, the paper shows that it is possible to do so, despite the lack of visible light beyond the sphere’s surface and the black hole’s reputation for being light sinks rather than light sources. To understand how to detect such a system in the first place, it would be helpful to understand what such a system would be designed for.
The authors study six different sources of energy that a possible Dyson ball could accumulate around a black hole. They are the ubiquitous cosmic microwave background radiation (which would wash out the ball no matter where it is), the Hawking radiation from the black hole, its accretion disk, the Bondi accretion, its corona, and its relativistic jets.
Some of these energy sources are more powerful than others, and the energy from the black hole’s accretion disk drives the beam in terms of capturing potential energy. Other types of energy require completely different engineering challenges, such as capturing the kinetic energy of the relativistic jets emerging from the poles of the black hole. Apparently, size plays a role in how much energy these black holes emit. The authors focus primarily on stellar-mass black holes as a good point of comparison with other possible energy sources. At this size, the accretion disk alone would provide hundreds of times the energy output of a main sequence star.
It would be impossible to build a Dyson sphere around any object of this size using currently known materials. But the type of civilization that would be interested in taking on such an engineering challenge would likely contain much stronger materials than we have today. Alternatively, they can work with known materials to create Dyson Swarm or Dyson Bubble, which don’t require a lot of physical force but lose some of the energy that a full ball could capture, adding multiple layers of complexity by coordinating orbital trajectories, and other factors. Any such structure must be outside the accretion disk to take full advantage of the energy emitted by the black hole.
Even a single ball around a single stellar-mass black hole would be enough to push whatever civilization that created it into the Type II region, giving it a level of energy production unimaginable with current technology. But even such a powerful civilization probably wouldn’t be able to bend the laws of physics. Regardless of the energy level, something will be lost due to the heat.
For astronomers, heat is just another form of light: infrared radiation, to be exact. According to the researchers, the heat emitted by the Dyson sphere around the black hole should be detectable by our current set of telescopes, such as the Wide-field Infrared Survey Explorer and the Sloan Digital Sky Survey, at a distance of at least about 10 kilobits per second. . This is about 1/3 of the distance in the entire
“> milky way. No matter how close they are, they will not appear like conventional stars, but they can be detected using the radial velocity method commonly used to find exoplanets.
While this theoretical work is helpful, there has certainly been no evidence for such a structure yet – the Fermi paradox remains. But given all the data that we are already collecting with these telescopes, it might be interesting to scan them again to check if there is heat coming from where it would not be expected. It would be useful to at least investigate what such a groundbreaking discovery might be in the first place.
Originally posted on universe today.
Reference: “Dyson’s ball around a black hole” by Tiger Yu, Yang Hsiao, Tomotsugu Goto, Tetsuya Hashimoto, Daryl Jo D. .- W. Wu, Simon C .; Ho and Ting-Yi Lu, June 29, 2021, Available here. Astrophysics> High-energy astrophysical phenomena.