Black holes can evaporate, according to a new study

In 1974, Stephen Hawking made one of his most famous predictions: that black holes evaporate completely.

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "According to Hawking's theory, black holes are not perfectly "black" but rather emit particles. Hawking thought that this radiation could possibly siphon enough energy and mass black holes to make them disappear. It is generally assumed that the theory is true but that it was once almost impossible to prove. "Data-reactid =" 23 "> According to Hawking's theory, black holes are not perfectly" black "but actually emit particles, which, Hawking believed, could possibly siphon enough energy and mass for them. to disappear.

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "For the first time, physicists have shown this radiation elusive Hawking – at least in a laboratory Although the Hawking radiation is too weak to be detected in space by our current instruments, physicists have now seen this radiation in a black hole analog created in the past. Help sound waves and the weirdest and coldest material in the universe.[[[[9 ideas about black holes that will blow your mind]"data-reactid =" 24 "> For the first time, physicists have shown this elusive Hawking radiation – at least in a laboratory – although the Hawking radiation is too weak to be detected in space by our current instruments, it has this radiation in a black hole analog created using sound waves and the coldest and weirdest matter of the universe. [9 Ideas About Black Holes That Will Blow Your Mind]

Pairs of particles

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Black holes exert a gravitational force so incredibly powerful that even a photon, who travels to the speed of light, could not escape. While the void of space is generally considered empty, the uncertainty of quantum mechanics is that the void teems with virtual particles who fly in and out of existence in the matter-antimatter pairs. (Antimatter the particles have the same mass as their material counterparts, but the electric charge is opposite.) "data-reactid =" 26 "> The black holes exert an incredibly powerful gravitational force, even a photon moving at the speed of light could not escape While space vacuum is generally considered empty, the uncertainty of quantum mechanics indicates that it is teeming with virtual particles that come and go in matter-antimatter pairs. antimatter particles have the same mass as their counterparts in the material, but the opposite electric charge.)

Normally, after the appearance of a pair of virtual particles, they cancel immediately. However, next to a black hole, the extreme forces of gravity separate the particles, one particle being absorbed by the black hole while the other is propagated in space. The absorbed particle has a negative energy, which reduces the energy and mass of the black hole. Swallow enough of these virtual particles and the black hole will eventually evaporate. The particle that escapes becomes known as Hawking radiation.

This radiation is weak enough that we can observe it in space for the moment, but physicists have found some very creative ways to measure it in a laboratory.

A horizon of cascade events

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "The physicist Jeff Steinhauer and his colleagues at the Technion – The Israeli Institute of Technology Haifa used an extremely cold gas called Condensate of Bose-Einstein to model the event horizon of a black hole, the invisible border beyond which nothing can escape. In a stream of this gas, they placed a cliff, creating a "cascade" of gas; when the gas flowed on the waterfall, it turned enough potential energy in kinetic energy data-reactid = "30"> Physicist Jeff Steinhauer and his colleagues at the Technion – Israel Institute of Technology in Haifa used an extremely cold gas called Bose-Einstein condensate to model the horizon of events. from a black hole, the invisible border beyond which nothing can escape. In a stream of this gas, they placed a cliff, creating a "cascade" of gas; when the gas has crossed the waterfall, it has turned enough potential energy into kinetic energy the energy flows faster than the speed of sound.

Instead of particles of matter and antimatter, researchers used pairs of phonons, or quantum sound waves, in the gas stream. The slow-side phonon could travel against the flow of gas away from the cascade, while the fast-side phonon could not be trapped by the "black hole" of the supersonic gas.

"It's like you're trying to swim against a current that was going faster than you could," Steinhauer told Live Science. "You'd feel like you're going forward, but you're really going back in. And it's like if a photon in a black hole was trying to get out of the black hole but that's it." he was gravitational in the wrong direction. "

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Hawking predicted that the radiation of the particles emitted would be continuously spectrum of wavelengths and energies. He also said that it could be described by a single temperature that depended solely on the mass of the black hole. The recent experiment confirmed these two predictions in the sonic black hole. "Data-reactid =" 33 "> Hawking predicted that the radiation from the emitted particles would be in a continuous spectrum of wavelengths and energies.He also explained that it could be described by a single temperature that depended only on the mass of the black hole. The recent experiment confirmed these two predictions in the sonic black hole.

"These experiments are a tour de force," Renaud Parentani, a theoretical physicist at the Laboratory of Theoretical Physics at Université Paris-Sud, told Live Science. Parentani also studies analog black holes but from a theoretical angle; he was not involved in the new study. "It's a very specific experience." On the experimental side, Jeff [Steinhauer] is really, at present, the world's leading expert in the use of cold atoms to probe the physics of black holes. "

Parentani, however, stressed that this study was "a step in a long process". In particular, this study did not show any correlation between the phonon pairs at the quantum level, which is another important aspect of Hawking's predictions.

"The story will continue," said Parentani. "This is not the end at all."

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Originally published on Science live."data-reactid =" 41 ">Originally published on Science live.