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Original link:/Alien-Suction-Black hole-Energy

An imaginary picture of a black hole seen from a planet.

Source: Mark garrick/Science Photo Gallery

Scientists recently said that when aliens lick the energy of black holes, we may find their whereabouts.

This method of collecting energy may leave traces outside the horizon of the rotating black hole. Within this boundary, the gravity of the black hole is so strong that neither matter nor energy can escape. This phenomenon can at least partially explain the plasma flares that scientists have found near highly unstable space-time regions such as black holes. 65438+1October 13 A new study published in american physical society's Journal of Physical Review D puts forward this view.

At present, this is just a very sci-fi idea, because the nearest black hole is more than 1000 light years away. Although in the foreseeable future, humans may not be able to use the energy of these behemoths, rotating black holes may indeed become an inexhaustible source of energy for advanced civilizations.

Luca Comisso, a co-author of the study and an astrophysicist at Columbia University in new york, said that the next step would be to find out how aliens extract energy from black holes.

"In this paper, we only discussed the theoretical part," he said. "But now I am working with one of my colleagues, trying to apply the theory to reality, looking for extraterrestrial civilization, and trying to understand what signals we need to find."

Spin black hole

A fictional black hole in the sci-fi movie Interstellar.

This is the fourth time in 50 years that scientists have proposed a new method to absorb energy from rotating black holes. The most famous research was put forward by physicist roger penrose in 1969. He won the 2020 Nobel Prize in Physics for his work on black holes.

He proposed a mechanism called Penrose process. According to this mechanism, a particle will break in half next to a black hole rotating at nearly the speed of light. Then, before falling into the event horizon of the black hole, some particles will fall into a space-time chaotic region called the energy layer.

"Because the black hole rotates too fast, it disturbs space-time like a vortex," Comisso said.

According to calculations, objects falling into the energy layer may have negative energy, which is impossible in other parts of the universe. "The energy plane is the only tiny space where this can happen," Comisso said.

He said that because adding particles with negative energy into a black hole is equivalent to extracting energy from the black hole, aliens can extract the energy of the black hole by capturing the other half particles that escape the strong gravity of the black hole. "It's like feeding negative energy to a black hole."

Penrose only considered splitting a particle in half in his initial research, while the latest research includes generating a large amount of plasma in a huge thermal accretion disk around a black hole. Because plasma contains a lot of particles, it can generate a lot of energy accordingly.

In theory, black holes will gradually "evaporate" through Hawking radiation. But this process is too weak to be detected so far.

Magnetic reconnection

The orange accretion disk can be clearly seen in the first photo of a black hole taken by humans.

Felipe Asenjo, the co-author of Comisso and an astrophysicist at Adolphe Ibana University in Santiago, Chile, suggested that the plasma that extracts energy from a rotating black hole is caused by the phenomenon of "magnetic reconnection", that is, the strong magnetic field lines are entangled, broken and recombined outside the event horizon.

Comisso said that magnetic reconnection usually occurs on the surface of stars like the sun. Under this mechanism, when the plasma flare moves in the opposite direction, it will release a lot of energy.

Generally speaking, the plasma flare generated on a star will eventually fall back to the star or be ejected into space. However, due to the existence of the energy layer in the black hole, the falling plasma flow will have negative energy, and the other half of the escape flow will get more energy from the black hole.

This new research questions the theory of extracting energy from black holes put forward by astrophysicists Roger Brandford and Roman Zanuck in 1977. They claim that the magnetic field near the rotating black hole will not reconnect, but it will generate extra angular momentum in the escaping plasma stream, that is, "electromagnetic torque."

Comisso said that only after both conditions are tested can we determine which method can extract energy from the rotating black hole most effectively.

"In the future, people will use supercomputers to simulate these two situations and compare them." He said: "But at present, the situation is still unclear."

Comisso said that no matter which theory is finally confirmed, it can help astronomers to better estimate the spin rate of black holes and better determine the amount of energy released by black holes in the event horizon.

Mu Fu Xin media editorial department

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