Humans can theoretically harness energy from black holes

Date:4 March 2021

In new research, scientists say they’ve unlocked a new way to harness the enormous energy potential of black holes.

Their insights could apply to some far-future energy utility, sure—but it could also help other scientists who study black holes here and now to better understand them. The energy signature is released when forces that pull in opposite directions release huge blasts of energy.

“Black holes are commonly surrounded by a hot ‘soup’ of plasma particles that carry a magnetic field,” lead author Luca Comisso, a physicist at Columbia University, said in a statement. “Our theory shows that when magnetic field lines disconnect and reconnect, in just the right way, they can accelerate plasma particles to negative energies and large amounts of black hole energy can be extracted.”

Wait, they can accelerate plasma particles to . . . negative energy? That’s right. The scientists compare it to the idea of eating candy that somehow removes calories from your body instead of adding them—black holes “eat” particles with negative energy that then pulls out a discharge of energy. The black holes are, to follow the analogy, losing proverbial “weight” in the form of energy.

As magnetic fields disconnect and reconnect, like an unfathomably large cosmic version of regular refrigerator magnets, energy accumulates and is smashed out both against the black hole’s spin and with it. The energy that travels with the black hole’s spin is accelerated, and it’s this portion of energy that can clear the black hole to be gathered by some keen-eyed future builders.

This all takes place in a special area outside a rotating black hole called the ergosphere, Comisso says, “where the spacetime continuum rotates so fast that every object spins in the same direction as the black hole.” With an ambient velocity boost like a swift “moving sidewalk” in an airport, the already high relative speed of this energy reaches almost the speed of light.

It’s here, the scientists say, that we reach the threshold of an efficient hypothetical energy source.

“Achieving an efficiency greater than 100 percent is possible because black holes leak energy, which is given away for free to the plasma escaping from the black hole,” researcher Felipe Asenjo, from Universidad Adolfo Ibanez in Chile, said in the statement. “We calculated that the process of plasma energization can reach an efficiency of 150 percent, much higher than any power plant operating on Earth.”

Anyone trying to harness this energy phenomenon will be in a far future we’d likely barely recognize, but the study of black holes has tentacles that reach into many other scientists’ research. Any specific identification of this kind of energy signature helps researchers continue to narrow down their study of different kinds of black holes. Study of the ergosphere of rotating black holes dates back to just the 1970s.

The “bursty” plasma streams from black holes already light up the faraway sky for those who observe it, like lightning strikes from the cosmos. Indeed, these scientists are like the new astrophysical Benjamin Franklin, wondering and calculating what kite they should fly into the storm.

This article was written by Caroline Delbert and published in Popular Mechanics on 29 January 2021.


Picture: Pixabay

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