Black holes “are not the eternal prisons they were once thought. If you feel you are trapped in a black hole, don’t give up, there is a way out,” Stephen Hawking explained back in 2015. Hawking and his colleagues from the University of Cambridge suggest black holes have “soft hair” or “low-energy quantum excitations that release information when a black hole evaporates.”
Hawking told the world back in January that he had found a promising solution to his black hole information paradox (a potential explanation on how black holes can simultaneously erase information and yet still retain it).
He placed his paper up on the pre-print site arXiv.org for the physics community to review it. Now, around six months on, the research will soon be published in the peer-reviewed journal APS physics. In his research, he suggests how we may just be getting closer to figuring out this problem once and for all.
By definition, black holes have so much matter concentrated in a single point that nothing (not even light) can escape from within a certain area of space around them. This was a feature of Newtonian gravity; it has also been featured in Einstein’s General Relativity. When the full quantum theory of gravitation is developed, no doubt it will be a feature of that, too.
Hawking first talked about his theory in the 1970s, where he suggested that when a particle-antiparticle pair was sucked into a black hole, one particle would “radiate away into space” taking some energy from the black hole with it, known as “Hawking radiation.” This suggests that black holes could eventually disappear; however, his theory did not take into account what the black hole had swallowed — therefore resulting in a paradox.
Hawking now suggests that black holes have a soft hair halo that surrounds them, storing the lost information. This halo consists of “low-energy quantum excitations that release information when a black hole evaporates.” Putting it simply, they have a “signature” or record (similar to a vinyl record) of everything the black hole had swallowed, even after the hole has disappeared.
This theory seriously challenges the theory put forward by physicist John Wheeler, who said nearly 50 years ago that “black holes have no hair.” What he said was black holes are featureless, and can only be characterized by three parameters: mass, electric charge, and angular momentum.
Physicist Gary Horowitz said in an accompanying commentary:
“Four decades ago, Stephen Hawking proposed that black holes could destroy information — a conclusion that is incompatible with standard laws of quantum physics. This idea started a controversy known as the “black hole information problem” that even now has not been resolved.
The new study “shows that some of the assumptions that led to the information problem might be wrong. Their results do not completely solve the problem, but point to a promising research direction that might lead to its long-awaited solution.
“It will likely not explain how all the information is recovered when a black hole evaporates, since it is unclear whether all the information can be transferred to the soft hair.
“According to Einstein’s general theory of relativity, stationary black holes are completely determined by just three observable parameters: their mass, charge, and angular momentum. Almost none of the information about what fell into the black hole is visible from the outside. Physicist John Wheeler described this idea by saying that ‘black holes have no hair’.
“However, it is certainly possible that, following the path indicated by this work, further investigation will uncover more hair of this type, and perhaps eventually lead to a resolution of the black hole information problem.”
The new theory is a big deal, not only for Hawking, but also the scientific community, as it may be the key to the so-called “black hole information problem,” which Hawking has been working on now for four decades. However, if you’re determined to escape from a black hole, there is still no way to do it obeying current laws of physics as we know them.