Could we harness energy from black holes?

Jan 13, 2021

(Nanowerk News) Einstein’s astounding prediction of universal relativity – the theory that links space, time, and gravity – is that rotating black holes have a large amount of energy available to tap.

For the past 50 years, scientists have tried to propose methods to release this power. Nobel physicist Roger Penrose theorized that particle decomposition could extract energy from a black hole; Stephen Hawking proposed that black holes could release energy through quantum mechanical emissions; while Roger Blandford and Roman Znajek suggest electromagnetic torque as a major energy extraction agent.

Now, in a study published in the journal Physical Review D. (“Magnetic reconnection as a mechanism for extracting energy from rotating black holes”), physicists Luca Comisso of Columbia University and Felipe Asenjo of Universidad Adolfo Ibanez in Chile, found a new way to extract energy from black holes by cutting and rejoining with magnetic field lines. near the event horizon, the point where nothing, not even light, can escape the gravitational pull of the black hole. Plasma near event horizon about to be destroyed by a rotating black hole. (© IOP Publishing)

“Black holes are often surrounded by hot ‘soup’ of plasma particles carrying a magnetic field,” said Luca Comisso, a research scientist at Columbia University and the study’s first author.

“Our theory shows that when magnetic field lines disconnect and reconnect, in exactly the right way, they can accelerate plasma particles to negative energy and large amounts of black hole energy can be extracted.”

This finding could allow astronomers to better estimate black hole spin, drive black hole energy emissions, and could even provide an energy source for advanced civilization needs, Comisso said.

Comisso and Asenjo built their theory on the premise that magnetic field reconnection accelerates plasma particles in two different directions. One plasma flow is pushed against the spin of the black hole, while the other is driven in the direction of the spin and can escape the black hole claws, which release power if the plasma has the black hole is swallowed by negative energy.

“It’s like someone could lose weight by eating candy with negative calories,” said Comisso, who explained that a black hole loses energy by essentially eating energy-negative particles. “This may sound strange,” he said, “but it can happen in a region called the ergosphere, where the space-time continuum rotates so fast that all objects are spinning in the same direction as the black hole. ”

Inside the ergosphere, magnetic reconnection is so extreme that the plasma particles are accelerated to speeds approaching the speed of light.

Asenjo, professor of physics at the Universidad Adolfo Ibez and coauthor on the study, explained that the relatively high speed between trapped and escaped plasma streams is what allows the proposed process to draw a great deal of energy from the black hole.

“We calculated that the process of plasma energetics can reach 150 percent efficiency, which is much higher than any power station operating on Earth,” Asenjo said. “Achieving efficiency in excess of 100 percent is possible because black holes release energy, which is given free of charge to the plasma escaping the black hole.”

The energy extraction process envisaged by Comisso and Asenjo may already be operating in large numbers of black holes. That may be what drives black hole flares – powerful radiation bursts that can be detected from the Earth.

“Our growing knowledge of how magnetic reconnection occurs in the vicinity of the black hole may be crucial for guiding our interpretation of current and future telescope observations of black holes, such as those from the Horizon Event Telescope,” he said Asenjo.

While it might sound like science fiction stuff, mining energy from black holes could be the answer to our future power needs.

“Thousands or millions of years from now, humanity may be able to survive around a black hole without harnessing the energy of stars,” said Comisso. “It’s basically a technological problem. If we look at the physics, there’s nothing stopping it.”

The study, Magnetic reconnection as a mechanism for extracting energy from rotating black holes, was funded by the National Institute of Science, NASA’s Windows on the Universe initiative, and the Chilean National Fund for Scientific and Technological Development.

“We look forward to the potential translation of seemingly esoteric studies of black hole astrophysics into the practical realm,” Lukin said.

“The ideas and concepts discussed in this work are truly fascinating,” said Vyacheslav (Slava) Lukin, program director at the National Science Foundation. He said NSF aims to catalyze new theoretical endeavors based on frontier observations, bringing together theoretical physics and observational astronomy under one roof.

“We look forward to the possible translation of seemingly esoteric studies of black hole astrophysics into the practical realm,” he added.

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