In 1960, the British-American mathematical and theoretical physicist Freeman Dyson (who passed away in 2020), published an article in Science magazine that changed the way we began to talk about extraterrestrial civilizations. In it, Dyson surmised that a sufficiently advanced civilization would harness the power of its natal star to generate power on a large scale. He also proposed that nascent search for extraterrestrial intelligence (SETI) programs should “search for sources of infrared radiation” to “accompany the recently initiated search for interstellar radio communications.”
Now, a new study has presented some novelties in this regard, arguing that we could locate advanced extraterrestrial civilizations by looking for precisely this type of energy harvester called a Dyson sphere, which extracts energy from a black hole.
“In this study, we consider an energy source from a well-developed Type II or Type III civilization. They need a more powerful source of energy than their own Sun,” the authors write in their article published in the Monthly Notices of the Royal Astronomical journal. Society. “An accretion disk, corona, and relativistic jets could be potential powerhouses for a Type II civilization. Our results suggest that for a stellar-mass black hole, even at a low Eddington ratio, the accretion disk could provide hundreds times brighter than a main sequence star . “
This megastructure that collects the energy of the star at the source, initially proposed that infrared emissions of thermal energy could escape as the Dyson structure captured and converted the stellar energy , which could hypothetically reveal the presence of these structures as a signature. to identify alien civilizations.
But what if it were around a black hole?
According to experts, the possible emission of the accretion disk around a black hole, its corona and even the relativistic jets emitted by the black hole, would be ideal to take advantage of them as an energy source and said civilization would not have to worry about its energy needs during a lot of time. At work, the focus is on a Kardashev-scale Type II civilization that can harness roughly a trillion times the energy humanity has used in 2020. With that in mind, a Dyson sphere around a black hole it would be the most efficient solution.
In fact, the supermassive black hole in our galaxy, Sagittarius A *, could provide more energy than about 100,000,000 suns.
Although we cannot do it right now, there could be extraterrestrial civilizations that can do it. If such a structure existed in the Milky Way, we could detect it, although much more research would be needed to confirm that it is an artificial source.
Referencia: A Dyson sphere around a black hole Tiger Yu-Yang Hsiao, Tomotsugu Goto, Tetsuya Hashimoto, Daryl Joe D Santos, Alvina Y L On, Ece Kilerci-Eser, Yi Hang Valerie Wong, Seong Jin Kim, Cossas K-W Wu, Simon C-C Ho … Show more Monthly Notices of the Royal Astronomical Society, Volume 506, Issue 2, September 2021, Pages 1723–1732, https://doi.org/10.1093/mnras/stab1832