One of the longest surviving mysteries of black holes is what happens to things when it drops inside. Information cannot move quicker than light, so it cannot discharge from a black hole, but we know that black holes contract and fade away over time, emitting Hawking radiation. This has troubled researchers for more than 40 years. Information cannot just vanish.

Now, physicists Chris Adami, from the University of Ottawa and Kamil Brádler, from Michigan State University, have been capable of showing that the information does not get lost, but is transported from the black holes into the above-mentioned Hawking radiation, possibly solving a long-surviving mystery of cosmology. More than 40 years ago, Stephen Hawking proposed the idea that although nothing can come out from a black hole, there should be a definite amount of particles produced from the outer end of the black hole's event horizon. Over time, this emission would take energy from a black hole, causing it to contract and fade away.

The emission wasn’t from the black hole itself, so scientists began to surprise what happens to the information inside black holes when they vanish. If the information is forever lost there would be a violation of the laws of quantum mechanics, and this directed to the Black Hole Information Puzzle or Black Hole Information paradox.

Adami said in a statement, "The mystery was never left to rest because Hawking’s calculation was not able to detect the influence that the radiation, called Hawking radiation, has on the black hole itself. Physicists supposed that the black hole would shrink in time as the Hawking radiation carries away the black hole’s mass, but no one could prove this through scientific calculations."

Is Hawking radiation transmitting information out of black holes? NASA/JPL-Caltech

Numerous solutions have been put forward to solve the puzzle, but many physicists just supposed that it would be solved when we had a broad theory of quantum gravity. Though general relativity and quantum mechanics are two of humanity's greatest successes they do not work fit together. Black holes are one of those problems in which both theories are required. The model presented by Brádler and Adami looks at the quantum effect that created Hawking radiation. They used computer simulations to change the black holes, and they observed that the Hawking radiation was stealing energy and information out of the black hole.

Chris Adami said, "To perform these observations, we had to predict how a black hole interacts with the Hawking radiation field that surrounds it. This is because there presently is no theory of quantum gravity that could propose such an interaction. Still, it appears we made a well-educated supposition because our model is the same to Hawking’s theory in the boundary of fixed, unchanging black holes."

Their work, reported in Physical Review Letters, is a fascinating breakthrough in understanding black holes. Other groups are also trying to resolve the information paradox. But whereas it does not tell us plenty about the upcoming theory of quantum gravity, it indicates that this theory is there for us to learn.

Kamil Brádler said, "While our model is just that, a model, we were capable of showing that any quantum contact between black holes and Hawking radiation is very likely to have the similar properties as our model."

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