For decades, scientists have struggled with a complex mystery of physics: Could the enormous amounts of energy theoretically produced by rotating black holes ever be harnessed by human hands?
If future societies were able to eliminate this magnificent feat, the electricity supply of distant galactic civilizations seems to be guaranteed, and now scientists have a new explanation of how such an exotic extraction could ever be possible.
“Black holes are usually surrounded by a hot ‘soup’ of plasma particles carrying a magnetic field,” explains astrophysicist Luca Comisso of Columbia University.
“Our theory shows that when magnetic field lines are disconnected and reconnected, in the right way, they can accelerate plasma particles to negative energies and large amounts of energy can be extracted from the black hole.”
The new work of Comisso, co-author of the physicist Felipe A. Asenjo of the Adolfo Ibáñez University of Chile, provides a new prism to glimpse how the extraction of energy from a rotating black hole could work.
Given their extreme mass, it is natural to assume that black holes also contain an extreme amount of energy. Unfortunately, everything is locked at the bottom of a slippery well of space-time.
In conditions where this mass rotates, it might be possible to submerge a finger in this immense pool of energy as the slopes of space-time crawl.
The eminent physicist and mathematician Roger Penrose of Oxford University suggests an ingenious method. In what became known as the Penrose process, energy could theoretically be extracted from the region outside the event horizon of a black hole, called the ergosphere, within which space-time is rotated by effects of black hole rotation.
Penrose’s calculations suggested that if a particle split into two parts inside the ergosphere, with one piece falling on the event horizon and the other escaping the gravitational traction of the black hole, the energy produced by the escaping object would theoretically be extractable, if virtually impossible.
This famous idea was experimentally verified by scientists in a paper published just a few months ago, but it is not the only suggested way to harness the energy of a spinning black hole.
Hawking radiation, based on quantum mechanical emissions, is another form, such as the Blandford-Znajek process, in which energy can be extracted electromagnetically through the magnetic field around a black hole.
In Comisso and Asenjo’s analysis, magnetism also plays a central role, specifically, as magnetic field lines break and join inside the ergosphere, but it also reformulates part of the thought of the process of Penrose.
As magnetic reconnections occur outside the event horizon: the division of plasma particles accelerates to speeds approaching the speed of light in two different directions: a plasma flux could fall to the event horizon and the other escaped.
From the perspective of the black hole, the falling particle would be impregnated with a negative amount of energy. From outside the black hole, the particle that would come out would have positive energy that could be put into operation.
By this method, escaping accumulated energy plasma flows could theoretically serve as a virtually unlimited source of free energy, as long as the black hole continues to swallow negative energy plasma, i.e..
“We calculated that the plasma energy process can achieve an efficiency of 150 percent, far superior to any power plant operating on Earth,” Asenjo explains.
“Achieving more than 100% efficiency is possible because black holes filter energy, which is delivered free of charge to the plasma escaping from the black hole.”
While it is likely to be unlikely that it will somehow be able to exploit this power generation in a practical way, this does not mean that it is completely useless.
From an astronomical perspective, the phenomenon could be the one that powers the flares of the black hole, which represent large releases of radiation energy that are not harnessed in space.
“Unlike the Blandford-Znajek process, in which the extraction of rotational energy is obtained through a purely electromagnetic mechanism, the energy extraction mechanism described here requires a non-zero inertia of particles. “, write the authors.
“This mechanism is also different from the original Penrose process, as magnetic energy dissipation is needed to produce the negative energy particles. It is clear that all mechanisms extract rotational energy from the black hole by feeding the black hole with negative energy. and angular momentum “.
The findings are reported in Physical check D.