What is Stephen Hawking's main achievement?

He proved the singularity theorem, discovered Hawking radiation, put forward a conjecture without boundary conditions, and created a brief history of time.

1, singularity theorem

In the early stage of the expansion of the universe, space-time is highly distorted and the radius of curvature is very small. BIGBANG has an initial singularity, where time begins. There is a singularity inside the black hole, where time ends.

Hawking studied Einstein's theory of gravity in the 1970s. He found that under very general conditions, there must be singularities in space and time, and space-time seems to be infinitely curved. However, it was not clear at that time whether the singularity really existed.

Roger penrose of Birkbeck College in London confirmed that black holes do form singularities. Later, Penrose and Hawking applied the same idea to the whole universe and showed that Einstein's theory predicted the singularity of our distant past, the Big Bang.

Hawking and Penrose proved the famous singularity theorem together, for which they won the Wolf Prize in Physics in 1988.

2. Hawking radiation

Hawking radiation is a theory about black holes. The gist is that black holes emit blackbody radiation, which was established by Stephen Hawking in 1972. Hawking's radiation theory can explain how to reduce the mass of black holes and lead to the evaporation of black holes.

Hawking radiation (sometimes called Berkenstein-Hawking radiation) is a theoretical prediction about the thermodynamic properties of black holes put forward by British physicist Stephen Hawking.

3. No boundary conditions

The universe is a quantum transformation from Euclidean space to Rockwell space-time. From the point of view of quantum universe or cosmic wave function, Euclidean space comes from absolute nothingness and realizes the idea that the universe is created out of nothing? .

This Euclidean space is a four-dimensional sphere. In the initial stage of the transformation from four-dimensional sphere to Rockwell space-time, space-time is a skyrocketing stage that can be described by De Sitter metric. Then inflation ends, and then it is described by the big bang model. In this cosmic model, space is limited, but there is no boundary, so it is called a closed cosmic space model.

Since Hawking put forward this theory, almost all quantum cosmology research has been carried out around this model. This is because its theoretical framework is only effective for closed spaces.

He wrote A Brief History of Time, which conquered 30 million readers all over the world. The black hole theory perfectly unifies quantum theory and thermodynamics in Hawking's radiation. The borderless quantum cosmology proposed by him in 1980s solved the "first push" problem that puzzled the scientific community for hundreds of years.

Extended data:

When Hawking was interviewed by BigThink, an American intellectual video sharing website, in August of 20 10, he made another astonishing remark, saying that the earth will be destroyed within 200 years, and there is only one way for human beings to survive: to emigrate to other planets.

Hawking said that if human beings want to continue, they must emigrate to Mars or other planets, and the earth will die sooner or later. Hawking said: "mankind has entered an increasingly dangerous period, and we have experienced many life-and-death events."

Because of the genetic code of' selfish greed' carried in human genes, human beings are plundering the resources of the earth bit by bit. Humans can't put all their eggs in one basket, so they can't bet on one planet. "

Stephen william hawking, a famous British astrophysicist, made a surprising remark after admitting the existence of aliens: he claimed that it was theoretically feasible to fly humans into the future time machine.

The required conditions include wormholes in space or spacecraft with a speed close to the speed of light. However, Hawking also warned against going back to see history by time machine, because "only crazy scientists would want to go back to the past and' reverse cause and effect'."

Physicist Hawking mentioned in a documentary about the universe that human beings can actually build spaceships close to the speed of light and enter the future. Hawking even said that he didn't dare to talk nonsense and didn't want to talk more about the time machine because he was worried that others would regard him as a "freak". It was not until after the documentary that he dared to discuss it generously.

20 17, 165438+ 10, Hawking once again made a "prediction", saying that human beings may be extinct before 2600. Hawking believes that with the growth of the earth's population, energy consumption will increase and the earth will become a "burning fireball". Hawking believes that to get rid of this disaster, we can only find a planet suitable for human survival.

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