Share with friends and circles of friends with wechat scanning QR code < / P > < p > news on July 20. A recent new study based on string theory believes that black holes may form debris that humans can theoretically touch after evaporating, or a singularity that will not be shrouded by the event horizon < p > < / P > < p > since Stephen Hawking discovered that black holes will evaporate, people have known that black holes may disappear from the universe. But at present, scientists' opinions on gravity and quantum mechanics are not enough to describe the last moment of black hole life

but new research based on string theory suggests that black holes may form debris that humans can touch after they die < p > the importance of Hawking radiation < / P > < p > strictly speaking, black holes are not completely dark. In Einstein's general theory of relativity, all physical laws take the same form in any reference system. In this case, the black hole is always dark, and once it is formed, it will remain there forever. But in the 1970s, Hawking used quantum mechanics to explore what happened near the boundary of black holes, the so-called horizon < p > Hawking found that there is a strange interaction between the quantum field of the universe and the unidirectional potential barrier of the horizon, which provides a channel for energy to escape from the black hole. Energy will radiate outward from the black hole with slow and stable radiation and particle flow, which is later called Hawking radiation. As the energy escapes a little, the black hole will lose mass, shrink, and eventually disappear completely < p > Hawking radiation causes the so-called black hole information paradox. Scientists believe that all information about the matter falling into the black hole will pass through the event horizon. But Hawking radiation itself does not carry any information. When the black hole finally disappears, where does all the information inside go

surpass Einstein

for physicists, the black hole information paradox shows that human beings have not yet understood something. This may be because humans do not understand the nature of quantum information, gravity or horizon. The "simplest" way to solve the information paradox of black holes is to construct a new gravitational theory that goes beyond Einstein's general theory of relativity

scientists have known that Einstein's general theory of relativity will fail at the center of a black hole. Black holes are tiny holes called singularities in space-time, where the density tends to infinity. The only way to correctly describe singularities is to introduce quantum gravity theory, which can correctly predict the performance of strong gravity on extremely micro scales

unfortunately, at present, scientists lack theoretical insights about quantum gravity. It is good to observe singularities directly, but according to general relativity, singularities are locked behind the event horizon of black holes, and human beings cannot touch them

but by studying the Hawking radiation process, scientists may be able to find a shortcut to the singularity and understand the physical phenomena that occur. As black holes evaporate, they become smaller and smaller, and their event horizon becomes closer and closer to the central singularity. At the last moment of a black hole's life, gravity becomes so great and the black hole itself becomes so small that scientists cannot correctly explain it with existing theories. Therefore, the best way is to introduce a new gravitational theory. In the new research, scientists use string theory to revise general relativity

naked singularity

this modified theory may not replace Einstein's general theory of relativity correctly, but it can allow scientists to study in depth what happens when gravity approaches the quantum limit. Recently, a theoretical team used the so-called Einstein dilaton Gauss bonnet gravitational theory to study the final state of black hole evapotranspiration. Relevant papers were published in May this year, and they were published on the preprint database arXiv in May

due to the correction of general relativity with string theory, there are a lot of approximations and guesses, and the details of the results of the research team are a little vague, but on the whole, it depicts what will happen after the black hole evapotranspiration

a key feature of Einstein inflation Gauss Bennett gravitational theory is that black holes have a minimum mass, so based on this, we can study what happens when a evaporating black hole begins to reach the minimum mass

according to the exact nature of the theory and the evolution process of the black hole, a small debris will be left in the process of black hole evapotranspiration. This fragment no longer has a horizon, so theoretically human beings can touch it. Although this debris is very strange, it will at least retain all the information that fell into the original black hole, so as to solve the black hole information paradox caused by Hawking radiation

another possibility is that the black hole reaches the minimum mass and leaves the event horizon, but there is still a singularity. In Einstein's general theory of relativity, this "naked singularity" does not seem to hold. But if they exist, they will open the door for human beings to enter the field of quantum gravity

at present, it is not clear whether Einstein inflation Gauss Bennett gravity theory is an effective path to quantum gravity. But such research helps physicists explain black holes, the most complex scene in the universe. (Chenchen)