Generation after generation has tirelessly explored the meaning of existence and life. However, the evolution of human thought is extremely slow and arduous. From Aristotle-Ptolemy
It took the geocentric theory 2000 years to talk about the evolution of Copernicus-Galileo's Heliocentrism. Surprisingly, although people know that everything in the world is
In the movement, it was not until Hubble discovered the law of redshift in the 1920s that the concept of the evolution of the universe came into human consciousness. People have never even
Never thought the universe would evolve. Newton's law of universal gravitation shows that the matter in the universe cannot be in a stable state under the action of gravity. Even in
In Einstein's general theory of relativity, the situation is not much better. In order to get a stable model of the universe, he introduced the cosmological constant into his theory.
They all hope to find a stable model of the universe in their own theories. It can be seen that the concept of the evolution of the universe was not produced in the minds of these geniuses.
To be fair, Hubble's observation marks the birth of modern cosmology. Hubble found that the farther a galaxy is, it can be inferred from the red shift of its spectrum.
The sooner you leave us, the whole universe is expanding. Back in time, it is estimated to be between 10 billion and 20 billion.
A few years ago, there was an epoch-making event, that is, the universe was born from an extremely dense and extremely hot state by the Big Bang. Gamov, tel 1948.
1998 published an article about the thermal big bang model, which made a surprising prediction. The radiation of the early big bang still lingered around us, but it was caused by
Due to the redshift caused by the expansion of the universe, the absolute temperature is only a few degrees. At this temperature, the radiation is in the microwave band. But in 1965, Peng
Before Zias and Wilson observed the cosmic microwave background radiation, people did not take this prediction seriously.
It is generally believed that Einstein's general theory of relativity is the correct theory to describe the evolution of the universe. Under the framework of classical general relativity, Hawking and
Penrose proved that there must be singularities in space-time under very general conditions, and the most famous singularities are those in black holes and BIGBANG.
The singularity of the explosion. At the singularity, all laws and predictability fail. Singularity can be regarded as the edge or boundary of space and time. Only considering the singularity
Only through boundary conditions can we get the evolution of the universe from Einstein's equation. Because the boundary conditions can only be given by the creator outside the universe, the universe's
Fate is in the hands of the creator. This is the first question that has puzzled human wisdom since Newton's time.
If there is no boundary between space and time, there is no need to disturb God with the first push. This can only be done in the theory of quantum gravity. Hawking admits
Because the quantum state of the universe is in the ground state, space-time can be regarded as a finite and unbounded four-dimensional surface, just like the surface of the earth, but much more.
It's only two-dimensional. All structures in the universe can be reduced to the minimum fluctuation allowed by the uncertainty principle of quantum mechanics. Calculate from some simple models
We can draw inferences consistent with astronomical observations, such as the cluster structure of galaxies and stars, large-scale isotropy and uniformity, time and space, etc.
Straight, that is, space-time is basically straight, which makes the development of galaxies and even life possible, as well as the direction arrow of time and so on.
The significance of Hawking's quantum cosmology lies in that it really makes cosmology a mature science. This is a self-sufficient theory, that is, in principle, only science.
By learning the laws, we can predict everything in the universe.
The author of this book is the most important contemporary general relativist and cosmologist. In 1970s, together with Penrose, he proved the famous singularity theorem.
Together, they won the Wolf Prize in Physics in 1988. He also proved the area theorem of black holes, that is, the area of black holes does not decrease with the increase of time. this
Naturally, people associate the area of a black hole with the entropy of thermodynamics. 1973, he considered the quantum effect near the black hole and found that the black hole would be like a black body.
The temperature of the same radiation is inversely proportional to the mass of the black hole, so that the black hole will gradually become smaller because of the radiation, but the temperature will get higher and higher, and it will
The last-minute explosion was over. The discovery of black hole radiation has its basic significance, which unifies gravity, quantum mechanics and statistical mechanics.
1974, his research turned to the theory of quantum gravity. Although people haven't got a successful theory, they have found some characteristics of it.
For example, space-time is not flat on the Planck scale (10-33 cm), but in a bubble state. Does not exist in quantum gravity.
In the pure state, causality is destroyed, so the unknowability rises from classical statistical physics and quantum statistical physics to the third level of quantum gravity.
After 1980, his interest turned to quantum cosmology.
The subtitle of this book is From BIGBANG to Black Hole. Hawking believes that his life's contribution is to prove black holes and big bang singularities within the framework of classical physics.
Inevitably, black holes are getting bigger and bigger; But in the framework of quantum physics, he pointed out that black holes become smaller and smaller due to radiation, and the singularity of the Big Bang is not only
Smoothed by quantum effects, the whole universe begins here.
The details of theoretical physics will change in the next 20 years, but as far as concept is concerned, it is quite complete now.
Hawking's life is very legendary. In terms of scientific achievements, he is one of the most outstanding scientists in history. His contribution was at the age of 20.
Being confined to a wheelchair for many years because of Luger's disease is really unprecedented. Because his contribution has a far-reaching impact on human concepts,
So there are many descriptions in the media about how he struggled with total paralysis. Nevertheless, one translator first met him at 1979.
The scene is still fresh in my mind. It was my first time to attend the seminar on general relativity of Hawking Group in Cambridge. When the door opened, suddenly a small voice came from behind my head.
There was a faint sound of electrical appliances. Looking back, I saw a thin man reclining in an electric wheelchair and turning on the electric switch himself. Try to be polite in translation.
He doesn't seem too surprised, but he is used to being surprised at the disability of people who meet for the first time. He needs a lot of effort to raise his head.
Before he lost his voice, he could only speak in a very weak deformed language, and he could only understand it after working and living with him for several months. He can't write.
In other words, reading must rely on a page-turning machine. When reading a document, you must spread out each page on a big desk, and then he drives a wheelchair, such as
Silkworms read page by page like mulberry leaves. People have to pay deep respect to the soul of human beings who pursue the ultimate truth with such a strong will.
Meaning. Every day, he drives a wheelchair from his home at No.5 Cambridge West Road, crosses the beautiful Jianhe River and the ancient King's College, and goes to the applied mathematics department in Silver Street.
Office of theoretical physics department. A slope was specially built in the department to facilitate him to take a wheelchair.
At Cambridge University, which is rich in academic tradition, he currently holds perhaps the highest professorship ever, which is held by Newton and Dirac.
Professor Luxon's Mathematics.