Prominent physicist Stephen Hawking, one of the “fathers” of the modern theory of black holes, now comes to challenge some central aspects of his own theory, which are considered almost “doctrines” of contemporary physics. In essence, he claims that there are no black holes, at least as they are imagined by the scientists so far.
In a “heretical” scientific prepublication – but not yet published in any official journal – the British scientist argues that the so-called event horizon, which in essence is a boundary of a black hole, does not exist because it is incompatible with quantum theory. Instead, Hawking suggests a concept of an “apparent horizon“, or a surface along which the light is not blocked forever from ‘escaping’ out of the black hole.
According to the “Nature“, Hawking calls for a redefinition of the concept of the black hole, above all, the abolition of the term “event horizon”, which is an invisible boundary that supposedly surrounds each black hole in the universe and prevents light from escaping. He says that the alternative “apparent horizon” only temporarily keeps matter and energy within the black hole, until it finally sets them “free” again, albeit in a different form.
Thus, while the dominant theory of physics supports that any escape from the black hole is impossible, Hawking insists that this cannot be happening because it is contrary to the quantum theory. Of course, as he admits, a complete explanation of the process requires an equally comprehensive theory that could unify gravity with the other fundamental forces in nature, which so far does not exist.
The new work of Hawking is expected to intensify discussions among physicists on the nature and function of black holes. The main argument is that quantum effects around a black hole force spacetime to “wave” so strongly that the existence of a clearly defined boundary such as the “event horizon” is impossible.
Already in the 70s, the British theoretical physicist had shown that black holes may slowly shrink, eliminating the so-called “Hawking radiation”. Now, he suggests that the “apparent horizon” is a real (temporary) boundary of a black hole. As Hawking writes in the new publication, “The absence of event horizons suggests that the concept of black hole that does not allow the light to escape is wrong.”
Unlike the event horizon, the ephemeral “apparent horizon” can disappear, which ultimately means that anything can eventually emerge from a black hole, in a different form from the original though. However, so far Hawking does not describe by what mechanism the disappearance of the “apparent horizon” may occur.
If all these are true, then the information consumed by a black hole is ultimately not destroyed, but merely “deformed” and can get out again in an unrecognizable form through the Hawking radiation.