This article is from the WeChat public account: principle (ID: principia1687) , author: David Crookes, title figure: Image by David Mark from Pixabay
Now you are ready to jump into a black hole. If you can find a way to survive (despite the difficulties) , what is waiting for you? If you try to look back, where will you go in the end, and what exciting story will you experience?
As Richard Massy’s (Richard Massey) said, all these questions have a simple answer: “No one knows.” As a researcher at the Royal Institute of Computational Cosmology at Durham University, Marcy knew the universe was full of unsolved mysteries. “Falling into the boundary of a black hole is actually stepping into an unknown world-once it falls, no one can send a message back.” Massy said, “They will be torn into pieces by huge gravity, so I don’t believe anyone falls into the black hole After that, where else can I go.
If this answer sounds disappointing, this is to be expected. After Einstein’s general theory of relativity predicted black holes based on the correlation between space-time and gravity, it is known that black holes originate from the small, dense core left by the death of massive stars. If the mass of this core is more than 3 times that of the sun, it will collapse under the action of huge gravity until all matter converges to a point. , and this singularity is the core of infinite black hole density.
The resulting black hole is so gravitation that even light can’t escape it. German astronomer KarlSchwarzschild (Karl Schwarzschild) proposed the “event horizon” (event horizon ) concept: Once light or matter crosses the event horizon, it can never escape. According to Massy’s explanation, when approaching a black hole, your body will be severely stretched due to tidal force. span>, and finally reach the singularity. As for the idea that you will appear somewhere else, such as the other side of a black hole, it seems that it is just heaven and earth.
1. What about a wormhole?
For years, scientists have been exploring whether black holes could become wormholes to other galaxies. Some people even speculate that wormholes can lead to another universe.
This idea has been around for some time. As early as 1935, Einstein collaborated with Nathan Rosen (Nathan Rosen) to put forward related theories, thinking that there may be a connection between the two in the universe Tunnels of different time and space. But it was not until the 1980s that this theory became popular. At the time, astrophysicist Kip Thorne (Kip Thorne) promoted a discussion about whether an object can pass through a wormhole.
Marcy said: “When I was a kid, I read Kip Thorne’s best-selling book on Wormholes, and this book made me interested in physics.” However, it now looks like Wormholes Does not seem to exist.
Thorn, who was a scientific consultant for the Hollywood film Interstellar, wrote in his book Science in Interstellar: “We have not been able to observe wormholes during any celestial aging process. Exist. “Thorne said, The space-time travel through these theoretical tunnels is likely to exist only in science fiction, and there is no reliable evidence that black holes allow such a crossing.
The problem is, we can’t approach them and observe them for ourselves. We can’t even take any pictures of the inside of the black hole-Since light cannot escape the huge gravity of a black hole, the camera cannot capture the image at all. Current theory suggests that any object that crosses the event horizon becomes part of a black hole. More importantly, because the time around the event horizon is also curved, this process will become extremely slow, so we can’t get the answer quickly.
“I think the standard story answer is that black holes lead to the end of time.” Douglas Finkbeiner, astronomy professor at Harvard University / span> said, “A distant observer cannot see how his astronaut friend fell into a black hole. Because of the redshift effect of gravity, everything we observe close to the event horizon will continue to turn red and dim. But this friend will eventually fall into a black hole and go somewhere beyond ‘forever’, no matter what that means. “
2. Maybe a black hole can lead to a white hole
It is true that if a black hole can lead to the other end of the galaxy or another universe, then the exit needs to be the opposite of a black hole. Is that a white hole? Russian cosmologist Igor Novikov (Igor Novikov) proposed the white hole theory in 1964. He believed that a black hole connected A white hole in the past. In contrast to black holes, light and matter can leave white holes but cannot enter.
Scientists have been exploring the potential connection between black and white holes. In 2014, physicists Carlo Rovelli (Carlo Rovelli) and Hal M. Hagard published a The research in Comment D states: “There is a classical metric that satisfies the Einstein equation outside the finite space-time region, where matter collapses into a black hole and then emerges from a white hole.” All matter underneath may be thrown, and black holes may become white holes after death.
The collapse of a black hole does not destroy the information in it. Instead, it experiences a quantum bounce, allowing all information to escape. If this is the case, this would explain Stephen Hawking to a certain extent (Stephen Hawking) theory that was proposed. In the 1970s, Hawking explored the possibility of black holes releasing particles and radiation due to quantum fluctuations.
Finkbina said: “Hawking believes that black holes have a limited lifetime.” In 1976, Hawking published a related paper in “Physics Review D”. According to his calculations, black holes lose energy due to radiation, shrink and eventually disappear. Because Hawking proposed that the radiation emitted by the black hole is random and does not contain any information falling into it, the explosion of the black hole will erase a lot of information.
This means that Hawking’s ideas contradict quantum theory, which believes that information is conserved. If information is lost, it will be more difficult to search for information, and the past and future will not be known. Hawking’s idea led to the emergence of the “black hole information paradox,” which has long plagued scientists. Some people say that Hawking is fundamentally wrong, and Hawking himself even declared his mistake at the 2004 academic conference in Dublin and overturned his original idea.
So, do we return to the concept discussed earlier, that is, the information absorbed by black holes will be thrown through white holes? Maybe it is.
In a paper published in the Physical Review Letters in 2013, Jorge Pullin, Louisiana State University, USA (Jorge Pullin ) and Rudolf Gambin, University of Uruguay (Rodolfo Gambin) Based on the theory of loop quantum gravity (loop quantum gravity) has studied black holes. They found that the closer the center is, the greater the gravity, but the gravity becomes weaker after passing through the center, and anything falling into the black hole will be thrown at the other end of the universe.
This study supports the hypothesis that black holes are only an entrance. In this study, the singularity does not exist, so things that fall into the black hole will not be destroyed by hitting the singularity. It also means that information does not disappear.
3. Maybe the black hole doesn’t lead anywhere
But physicist Ahmed Almahri (Ahmed Almheiri) , Donald Marov (Donald Marolf) , Joseph Pozinski (Joseph Polchinski) and James Sully (James Sully) still believe that based on Hawking’s theory There can be further discoveries.
These four scientists proposed the AMPS Fire Wall (or black hole fire wall) theory . According to their calculations, quantum mechanics can turn the event horizon into a huge wall of fire, and anything that comes in contact with it will burn out immediately. In this sense, black holes don’t lead anywhere, because there isn’t even anything that can enter a black hole.
However, this theory contradicts Einstein’s general theory of relativity. According to the equivalence principle (equivalence principle) in the theory of relativity, objects passing through the event horizon (Or people) will not be affected by extreme gravity and can easily fall into a black hole. The fire wall theory may follow the current laws of physics in areas beyond black holes in the universe, but even if it does not violate relativity, it also destroys quantum field theory and implies that information can be lost.
The artistic imagination of the tide collapse event. When a star gets too close to a supermassive black hole, the tidal force of the black hole tears it apart. (image