Scientists at the Center for Exoplanets and Habitable Worlds have suggested that extraterrestrial civilizations could use Dyson spheres – hypothetical space structures that harness the energy of a star – make computers. Such objects, much smaller than typical Dyson spheres, emit characteristic thermal radiation that can be detected with astrophysical instruments. A preprint of the article has been published in the arXiv repository. It is thought that Dyson spheres could be detected using radiation at mid-infrared wavelengths, but so far this research has been unsuccessful.
In their new work, scientists proposed changing the search criteria, depending not only on possible thermal radiation, but also on the possibility of using such structures. Capturing a star’s energy for later use is just one possible use for the Dyson sphere. It could also be a giant engine capable of moving stars (Shkadov engine), or a giant supercomputer (Matryoshka’s brain).
The Matryoshka brain has a nested structure, where the inner layer absorbs direct sunlight and the outer layers use the waste heat of the inner layer to optimize computing efficiency. In addition, an alien civilization could build such a structure gradually, section by section. Based on these assumptions, scientists applied radiation thermodynamics to Dyson spheres as computing machines to determine hypothetical observable properties.
It turned out that building shells does not have any advantages and the optimal use of mass corresponds to smaller and hotter Dyson spheres. In addition, there will be noticeable differences between structures still under construction and those already completed. This broadens the search parameters for objects with temperatures well above 300 Kelvin, because extracting energy from starlight is much more efficient near the star.