Hawking's theory of the anomalous properties of black holes confirmed

Hawking's theory of the anomalous properties of black holes confirmed
Hawking's theory of the anomalous properties of black holes confirmed

Physicists at the University of Sussex have shown for the first time that black holes can exert pressure on the environment. This unusual property of black holes was suggested by the famous theoretical physicist Stephen Hawking in 1974, but so far it has remained only a theory.

The study is published in the journal Physical Review D and is briefly covered by Phys.org. It is reported that the discovery was made by Professors Xavier Calmet and Folkert Kuipers, and they made it partly by accident.

Physicists conducted research that was not directly related to the subsequent discovery. They were engaged in calculations related to the nature of the so-called Schwarzschild black holes. In astronomy, it is generally accepted that this is the simplest black hole in which the core does not rotate. This type of black hole only has a singularity and an event horizon.

However, a new study has shown that in fact these mysterious objects are much more complex thermodynamic systems than was previously thought, and they have not only temperature, but also pressure.

The presence of pressure Calmet and Kuipers discovered when they used additional quantities in their calculations - they applied quantum gravitational corrections to the entropy of the black hole. Scientists themselves say that the findings puzzled them so much that they performed calculations over and over again. But each time the result was obtained, it was said that quantum gravity can lead to the appearance of pressure in black holes.

“Our discovery is that Schwarzschild black holes have pressure as well as temperature, and it is even more exciting considering that this was a complete surprise to us,” says Xavier Calmet.

The expert recalled that back in 1974, Stephen Hawking predicted what was discovered now. Then the famous physicist formulated the theory that black holes emit thermal radiation. Before that, it was believed that they are inert, that this is the last stage of the life of a dying heavy star.

A new study has yet to answer the question of what exactly triggers the pressure. According to the calculations of scientists, it is also not just small, but has a negative value. This means that under these conditions, the black hole will shrink, not grow, which is consistent with Hawking's prediction.

Now scientists intend to determine exactly how negative pressure is associated with Hawking radiation. The discovery may have interesting implications for attempts to link general relativity, which works at the macro level, with quantum mechanics, which works at extremely small scales.

Black holes are believed to play a key role in this understanding. According to general relativity, information that disappears outside a black hole can disappear forever. But the laws of quantum mechanics say that this simply cannot be. This paradox is called informational, and this is one of the main mysteries of black holes. Perhaps a new discovery will help resolve it.

“Our work is a step in that direction,” Calmet said. “Although the pressure exerted by the black hole we studied is tiny, the fact that it is present opens up many new possibilities for research … Hawking's remarkable intuition told us that that black holes are not black, but have a radiation spectrum very similar to that of a black body.This makes black holes an ideal laboratory for exploring the interactions between quantum mechanics, gravity and thermodynamics."

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