One possible solution is a Dyson-Ball – some kind of massive stellar engineering project that spans a whole star (or in this case a
“> Black hole) in an artificial shell that captures all of the energy given off by the body in its center. But even if it could capture all of the energy the black hole is sending out, the ball itself would still be losing heat. And that this heat loss will make it visible to us, shows new research results published by an international team led by researchers from the National Tsing Hua University in Taiwan.
Obviously, such a structure has not yet been discovered. However, the paper proves that this is possible, despite the lack of visible light beyond the surface of the sphere and the black hole’s reputation for being light sinks rather than light sources. In order to understand how such a system can be recognized, it would first be helpful to understand what such a system would be designed for.
The authors examine six different sources of energy that a potential Dyson sphere could collect around a black hole. They are the ubiquitous cosmic microwave background radiation (which would wash the ball away no matter where it was), the Hawking radiation of 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, with energy from the black hole’s accretion disk propelling the beam in terms of trapping potential energy. Other types of energy require completely different technical challenges, such as capturing the kinetic energy of relativistic jets emerging from the poles of the black hole. Apparently, size plays a big role in how much energy these black holes emit. The authors mainly focus on black holes with stellar mass as a good point of comparison with other potential energy sources. At this size, the accretion disk alone would provide a hundred times the energy output of a main sequence star.
It would be impossible to build a Dyson sphere around an object of this size with existing materials. But the kind of civilization that would be interested in taking on such a technical challenge would likely contain much stronger materials than we have today. Alternatively, they can work with known materials to create the Dyson Swarm or Dyson Bladder, which don’t require a lot of physical strength but lose some of the energy that a full ball could capture, multiple levels of complexity in coordinating Add orbits and other factors. Any such structure must be outside of the accretion disk in order to take full advantage of the energy that the black hole emits.
Even a single sphere around a single black hole of stellar mass would be enough to force any civilization that created it into the Type II region, giving it an energy output unimaginable with current technology. But even such a powerful civilization would most likely not be able to bend the laws of physics. Regardless of the energy level, some are lost to heat.
For astronomers, heat is just another form of light – infrared radiation, to be precise. According to the researchers, the heat emitted by the Dyson sphere around the black hole should be removed by our current telescopes, such as the Wide-field Infrared Survey Explorer and the Sloan Digital Sky Survey, up to a distance of at least 10. kilobits per second can be detected. . That is about 1/3 of the distance over the whole
“> Milky Way. No matter how close they are, they don’t appear like traditional stars but can be discovered using the radial velocity method commonly used to find exoplanets.
While this theoretical work is useful, there has certainly been no evidence to support such a structure – the Fermi paradox persists. But given all of the data we’re already collecting with these telescopes, it might be interesting to search them again to see if heat is coming from where it wouldn’t be expected. It would be useful at least to research what such a groundbreaking discovery could be.
Originally published in 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.