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Black jet nozzles could be driven by a strange "negative energy," astronomers



When the black hole actively feeds, something strange appears: huge powerful jet plasma plasma from its poles at speeds approaching the speed of light.

Due to the intense gravitational interactions in the game, it is exactly how these nozzles form, a mystery. But now, using computer simulations, the team of physicists has responded – particles that have "negative energy," extract energy from the black hole, and redirect it to the nozzles.

And for the first time, this theory united two different and seemingly incompatible theories about how energy can be drawn from a black hole.

The first is called the Blandford-Znajek process and describes how the black hole magnetic field can be used to gain energy from its rotation.

Since the material on the accretion disk swirls closer to the event horizon, the theory states that it is magnetizing more and more, creating a magnetic field. Within this field a black hole acts as a spinning conductor, causing tension between the poles and the equator; this voltage is discharged from the rods as a nozzle.

The second is called the Penrose process, and it relies on maintaining momentum rather than magnetism. The rotating energy of the black hole is not within the event horizon, but in an area outside it, it is called the ergosphere that comes into contact with the polar event horizon.

According to the Penrose process, if an object inside the area fell apart, one piece that plunged toward the black hole and the other fled out, against the rotation of the black hole, the outer part appeared with greater energy, rotation. This creates some sort of "negative energy".

Both of these scenarios are convincing, but we have not yet been sure of the right answer.

"How can energy be exhausted by rotating a black hole to make jets?" said theoretical physicist Kyle Parfrey of the Lawrence Berkeley National Laboratory. "It's been a long time."

The team proposed plasma simulation without collision (where particle collisions do not play a major role) in the presence of a strong gravitational field of the black hole. At the same time, they participated in the formation of pairs of electrons and positrons in electric fields, allowing for more realistic plasma density.

The resulting simulation naturally caused the Blandford-Znajek process – the electrons and the positrons move in opposite directions around the black hole and generate energy in an electromagnetic field that shoots from bars like nozzles.

But that too caused a change in the Penrose process. Due to relativistic effects, some particles appear to have "negative energy" when they disappeared into the black hole – which slowed the rotation of the black hole, only a small fraction.

"If you were right next to a particle, you would not see anything strange, but the distant observer seems to have negative energy," said Parfrey New Scientist.

"You will stay with this strange case where if it falls into a black hole, it will cause weight loss and rotation."

In fact, efficiency did not really help in the overall energy extraction, Parfrey noted, but it may be somehow connected to electric currents that turn magnetic fields.

Simulations also lack some components, such as the accretion disk, and the positron electron generation physics is not as detailed as it could be. The team will work on developing even more realistic simulations for more detailed study of the process.

"We hope to provide a more consistent picture of the problem," Parfrey said.

Team research was published in the journal Physical Revision Letters, and can be read in the full version on arXiv.


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