Researchers from the Israel Institute of Technology (Technion) were able, through a structure similar to a black hole created in 2016, to prove that one of the predictions of British physicist Stephen Hawking was right.
According to Hawking, a singularity is not only a monster that swallows matter and light; it would also spontaneously emit radiation – what became known as Hawking radiation, a weak and yet inexorable emission: if the black hole does not swallow enough matter to compensate for it, it will eventually evaporate and become extinct.
It has never been possible to observe or measure Hawking radiation, which has remained a hypothesis – until now. “If you enter the event horizon, there is no way out, even in the light. Hawking radiation begins outside the event horizon, where light can barely escape. This is very strange because there is nothing there; it is an empty space. However, this radiation starts from nowhere, goes out and goes towards Earth ”, physicist and study co-author Jeff Steinhauer told Phys.org.
Black holes are characterized by monstrous gravity; so gigantic that not even the light can escape from one. For that to happen, whatever was trapped beyond the event horizon (the boundary between being swallowed or not) would have to travel beyond the speed of light – and that, by the laws of physics, is impossible.
Hawking showed, however, that black holes still spontaneously emit light, thanks to quantum mechanics and “virtual particles”, fleeting elements of opposite energies that pair up with particles in the cosmos.
Thus, pairs of photons can be separated at the edge of the event horizon: while a particle with negative energy would be absorbed by the black hole, subtracting energy in the form of a mass from the singularity, another would escape through space – Hawking radiation.
“Hawking’s theory was revolutionary because it combined the physics of quantum field theory with general relativity. Verifying this quantum radiation is very difficult with a real black hole because Hawking radiation is very weak compared to background radiation from space. ”, Steinhauer told the Live Science website.