A remarkable prediction of Einstein’s general theory of relativity – the theory that connects space, time, and gravity – is that rotating black holes have enormous amounts of energy available for use.
For the past 50 years, scientists have tried to find methods to unleash this power. Nobel physicist Roger Penrose theorized that a disintegration of particles could draw energy from a black hole; Stephen Hawking proposed that black holes could release energy by emission of quantum mechanics; while Roger Blandford and Roman Znajek have suggested the electromagnetic couple as the main energy extractor.
Now, in a study published in the journal Physical examination D, physicists Luca Comisso of Columbia University and Felipe Asenjo of Adolfo Ibanez University in Chile, have found a new way to extract energy from black holes by breaking and joining magnetic field lines near the event horizon, the point from which nothing, not even light, can escape the gravitational pull of the black hole.
“Black holes are usually surrounded by a hot ‘soup’ of plasma particles that carry a magnetic field,” said Luca Comisso, a Columbia University researcher and first author of the study.
“Our theory shows that when the magnetic field lines disconnect and reconnect, in the right way, they can accelerate the plasma particles into negative energies and large amounts of black hole energy can be extracted.”
The discovery could allow astronomers to better estimate the rotation of black holes, generate black hole energy emissions and could even provide an energy source for the needs of an advanced civilization, Comisso said.
Comisso and Asenjo built their theory on the principle that reconnecting magnetic fields accelerates plasma particles in two different directions. One stream of plasma is pushed against the rotation of the black hole, while the other is propelled in the direction of the rotation and can escape the claws of the black hole, which releases energy if the plasma swallowed by the black hole has negative energy.
“It’s like a person can lose weight by eating candy with negative calories,” said Comisso, who explained that essentially a black hole loses energy by eating particles of negative energy. “It might sound strange,” he said, “but it can happen in a region called the ergosphere, where the space-time continuum spins so fast that each object spins in the same direction as the black hole. “
Inside the ergosphere, the magnetic reconnection is so extreme that the plasma particles are accelerated to speeds approaching the speed of light.
Asenjo, professor of physics at Universidad Adolfo Ibáñez and co-author of the study, explained that the high relative velocity between captured and escaping plasma streams is what allows the proposed process to extract massive amounts of black hole energy.
“We have calculated that the process of energizing the plasma can achieve an efficiency of 150 percent, far higher than any power plant operating on Earth,” Asenjo said. “Achieving greater than 100 percent efficiency is possible because black holes leak energy, which is given free to plasma escaping from the black hole.”
The energy extraction process envisioned by Comisso and Asenjo could already work in a large number of black holes. Perhaps this is what causes black hole eruptions – powerful bursts of radiation that can be detected from Earth.
“Our increased knowledge of how magnetic reconnection occurs near the black hole could be crucial in guiding our interpretation of current and future observations of black holes by the telescope, such as those from the Event Horizon Telescope,” Asenjo said.
While it may sound like science fiction, extracting energy from black holes could be the answer to our future energy needs.
“In thousands or millions of years, humanity may be able to survive around a black hole without harnessing the energy of stars,” Comisso said. “It’s basically a technological problem. If you look at the physics, there’s nothing stopping it.”
The study, Magnetic Reconnection as a Mechanism of Extracting Energy from Rotating Black Holes, was funded by the Windows on the Universe initiative of the National Science Foundation, NASA and the Chilean National Fund for Scientific Development and technological.
Vyacheslav (Slava) Lukin, program director at NSF, said the foundation aims to catalyze new theoretical efforts based on boundary observations at facilities such as the EHT, bringing together theoretical physics and astronomy observation under one roof.
“We look forward to the potential translation of seemingly esoteric studies from black hole astrophysics into the practical field,” Lukin said.
“The ideas and concepts covered in this work are really fascinating,” said Vyacheslav (Slava) Lukin, program director at the National Science Foundation. He said the NSF aims to catalyze new theoretical efforts based on frontier observations, bringing together theoretical physics and observational astronomy under one roof.
“We look forward to the potential translation of seemingly esoteric studies from black hole astrophysics into the practical field,” he added.
Black holes gain new powers when they spin fast enough
Luca Comisso and Felipe A. Asenjo. Magnetic reconnection as a mechanism for extracting energy from rotating black holes. Phys. Rev. D. DOI: 10.1103 / PhysRevD.103.023014, journals.aps.org/prd/accepted/… 304179756dd56a93a764
Provided by Columbia University
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