A technologically advanced alien civilization can draw the energy it needs from a black hole through a specific structure reminiscent of the so-called “Dyson ball”. This is the result of a new study by Tiger Hsiao, an astronomer at National Tsing Hua University, Taiwan. According to the researcher himself, and according to his colleagues, we should look for such structures around black holes and not around stars, as other scientists have suggested instead.
What is the domain of Dyson?
The Dyson field is a technological concept first described by Freeman Dyson, a British theoretical physicist, in 1960, based on an idea written by a science fiction writer from the same country, Olaf Stapledon.
The Dyson sphere, hypothetically created by a very advanced technological civilization, involves the insertion into orbit, around a cosmic body radiating energy, of a structure or group of structures, for example satellites, that collect part or even all of this energy. from it and transport it to where it will be used, usually a nearby planet or space station.
A Dyson sphere can be built around a star like the Sun as well as around other types of stars.
Dyson balls around black holes
A more special case is the formation of a Dyson ball around a black hole.
This is a special case because black holes do not emit any kind of energy, they attract matter at most and it is the last, before it goes beyond the event horizon, with its whirlpool to release energy through the so-called “growth disk”.
In this sense, black holes can, in fact, be considered a center of energy: of finite extension, and therefore with the possibility of building smaller balls, they are able to transfer an amount of energy around them that can be equivalent to that. of thousands of suns, something that should actually appeal to a sufficiently technically advanced civilization.
This view is supported by Tiger Hsiao himself, who, along with his colleagues, developed an understanding of whether such a structure is actually possible, especially at the level of obtaining an adequate amount of energy.
So the researchers ran some simulations by analyzing specific holes of different sizes: those with a mass five times the mass of our sun, those with a mass 20 times and those 4 million times more massive.
They range, therefore, from “small” black holes, those formed as a result of the collapse of a star, to black holes considered “supermass”, that is, black holes with masses millions of times the mass of our Sun. Over millions of years they obtained material from the surrounding region, which is usually located in the center of galaxies.
Harnessing the power of the accumulator disk
The researchers concluded that, in fact, the accretion disk, with its rapidly rotating gas and jets (material that flies away before crossing the event horizon at very high speed), could be used as an energy source.
The researchers estimated that a Dyson ball around a black hole of 20 solar masses could provide the same amount of energy as 100,000 Dyson balls around many stars. This would be much higher than energy efficiency. It is precisely for this reason that the researcher is convinced that we are wrong in the search for such structures around stars: about black holes that we must learn about.
Balls around black holes are much more efficient than those around stars
Moreover, as the researchers point out, due to their composition, accretion disks around black holes transmit their energy potential in a much more efficient and concentrated way than a star does with its continuous thermonuclear interactions and with energy emitted by practically every square centimeter. from the stellar surface.
Moreover, a hypothetical civilization can exploit in particular the relativistic jets of black holes by collecting not only electromagnetic radiation but also other types of energy that they produce such as kinetics.
Moreover, the energy of the so-called “Bondi accumulation” (or “Bondi-Hoyle-Littleton accumulation”), that is, the growth of material in the spherical region around cosmic objects such as neutron stars and black holes, can be exploited.
Structures are probably already recognizable today
According to the researchers, there will also be a way to locate such a structure around a stellar-mass black hole in our Milky Way. In fact, such a structure must be able to withstand very high temperatures, well above the melting point of metals.
Thus, the hypothetical refractory material in which the structure is built, will scatter a certain amount of heat and this scattering can be detected at ultraviolet wavelengths.
In fact, we have already built telescopes that can detect such structures in this way. Among them are, for example, NASA’s Hubble Space Telescope and the Galaxy Evolution Explorer (the latter was decommissioned in 2013 but can be searched through the data it collected).
Notes and insights
- Dyson’s ball around a black hole | Monthly Notices of the Royal Astronomical Society | Oxford Academy (he is)
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