One notable prediction of Einstein’s general theory of relativity – the theory that links space, time, and gravity – is that rotating black holes have enormous amounts of energy to tap into.
For the past 50 years, scientists have tried to develop methods of releasing this force. Noble physicist Roger Penrose theorized that particle decay could draw energy from a black hole; Stephen Hawking suggested that black holes could release energy through quantum mechanical emission; Roger Blandford and Roman Znajek suggested electromagnetic torque as the main means of generating energy.
Well, in a study published in the journal Physical examination D.Physicists Luca Comisso from Columbia University and Felipe Asenjo from Universidad Adolfo Ibanez in Chile have found a new way to extract energy from black holes by breaking and reconnecting magnetic field lines near the event horizon. From this point, 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 scientist at Columbia University and lead author of the study.
“Our theory shows that magnetic field lines, when properly separated and reconnected, accelerate plasma particles to negative energies and large amounts of energy can be extracted from black holes.”
This finding could allow astronomers to better estimate the spin of black holes, increase black hole energy emissions and even provide an energy source for the needs of an advanced civilization, Comisso said.
Comisso and Asenjo built their theory on the premise that reconnecting magnetic fields accelerates plasma particles in two different directions. One plasma stream is pushed against the black hole’s spin while the other is driven in the direction of the spin and can escape the black hole’s clutches, releasing current when the plasma swallowed by the black hole has negative energy.
“It’s like a person could lose weight if they eat candy with negative calories,” said Comisso, who explained that essentially a black hole loses energy when it eats particles with negative energy. “That may sound strange,” he said, “but it can happen in a region called the ergosphere, where the space-time continuum rotates so fast that every object rotates in the same direction as the black hole.”
Within 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 speed between captured and exiting plasma streams enables the proposed method to extract enormous amounts of energy from the black hole.
“We have calculated that the process of plasma excitation can achieve an efficiency of 150 percent, much higher than any power plant on earth,” said Asenjo. “An efficiency of more than 100 percent is possible because black holes lose energy, which is given free of charge to the plasma emerging from the black hole.”
The energy recovery process planned by Comisso and Asenjo may already be running in a large number of black holes. That could be what powers black hole torches – powerful bursts of radiation that can be captured from Earth.
“Our expanded knowledge of how magnetic reconnections occur near the black hole could be critical to our interpretation of current and future telescope observations of black holes such as those used by the Event Horizon Telescope,” said Asenjo.
While it sounds like science fiction, extracting energy from black holes could be the answer to our future electricity needs.
“In thousands or millions of years, humanity could be able to survive around a black hole without using the energy of the stars,” Comisso said. “It’s essentially a technological problem. If we look at physics, there’s nothing stopping it.”
The study Magnetic Reconnection as a Mechanism for Harvesting Energy from Rotating Black Holes was funded by the Windows on the Universe initiative of the National Science Foundation, NASA, and the National Fund for Scientific and Technological Development in Chile.
Vyacheslav (Slava) Lukin, program director at NSF, said the foundation intends to catalyze new theoretical efforts based on frontier observations in facilities like the EHT, bringing theoretical physics and observational astronomy together under one roof.
“We look forward to the possible translation of seemingly esoteric studies on black hole astrophysics into practice,” said Lukin.
“The ideas and concepts discussed in this paper are really fascinating,” said Vyacheslav (Slava) Lukin, program director at the National Science Foundation. He said NSF aims to catalyze new theoretical endeavors based on boundary observation and bring theoretical physics and observational astronomy under one roof.
“We look forward to the possible translation into practice of seemingly esoteric studies of black hole astrophysics,” he added.
Black holes get new powers when they spin fast enough
Luca Comisso and Felipe A. Asenjo. Magnetic reconnection as a mechanism for generating energy from rotating black holes. Phys. Rev. D.. DOI: 10.1103 / PhysRevD.103.023014, journals.aps.org/prd/accepted/… 304179756dd56a93a764
Provided by Columbia University
Quote: Could we use energy from black holes? (2021, January 13) Retrieved January 14, 2021 from https://phys.org/news/2021-01-harness-energy-black-holes.html
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