Hawking: we are close to answering the question of where humans come from.

 

Hawking, a famous cosmic physicist who is visiting Hong Kong, presided over a speech entitled "the origin of the universe" at the University of Science and Technology Gymnasium on the afternoon of the 15th, and then answered the pre-selected questions. More than seats in the gymnasium are full. Photo by Tan Daming from China News Service

Professor Hawking, the internationally renowned and most influential astronomical physicist, presided over a lecture at the Hong Kong University of Science and Technology yesterday entitled "the origin of the universe". The scientific author named "Modern Einstein" declared that: cosmology is a very exciting and active discipline. We are close to answering this old question: why are we here? Where do we come from? Over one thousand eight hundred audience members and tens of thousands of Hong Kong people listened to Hawking's speech through a speech synthesizer in front of the TV screen.

 

 

Hawking's speech is as follows:

According to the legend of the boshongo people in China and Africa, the world is only dark, water and the great Bumba god. One day, Bumba suffered from stomachache and vomited out of the sun. The sun burned some water and left the land. He still had a stomachache and spit out the moon and stars, then spit out some animals, such as leopards, crocodiles, turtles, and finally people.

Like many other myths, the myth of this century tries to answer the question we all want to ask: Why are we here? Where do we come from? The general answer is that the origin of mankind is more recent. Humans are making continuous advances in knowledge and technology. In this way, it cannot exist for so long. Otherwise, it should make greater progress. This should be clear even earlier.

Aristotle: The universe has no beginning

The universe has existed for an infinite period of time.

For example, the founding of the world is scheduled to be held at nine o'clock A.M. on January 1, October 23, 4004 BC according to Bishop Usher. On the other hand, the natural environment of mountains and rivers changes little in the life cycle of people. So people usually regard them as a constant background. Either an empty landscape has existed for a long time, or it was created at the same time as humans.

However, not all people like the idea that the universe has a beginning. For example, the most famous Greek philosopher Aristotle believes that the universe has existed for an infinite period of time. Something eternal is more perfect than something creative. He suggested that we should see that development is in this situation because of floods or other natural disasters, which repeatedly bring civilization back to its infancy. The motive behind belief in the eternal universe is to avoid turning to God-intended interference to create and start the universe. On the contrary, those who believe that the universe has a beginning will regard the beginning as an argument for the existence of God, and regard God as the first reason or motive force of the universe.

Time before the beginning of the universe is meaningless

Time is absolute, and time passes from the infinite past to the infinite future

If people believe that there is a beginning in the universe, the obvious question is, what happened before the beginning? What is God doing before he creates the universe? Is he preparing a hell for those who ask such questions? German philosopher imanur Kant is very concerned about the beginning of the universe. He thinks that, no matter whether or not the beginning of the universe will lead to logical conflicts or the inverse of the two laws. If the universe has a beginning, why wait for an unlimited period of time before it starts. He calls this a question. On the other hand, if the universe already exists for an infinite period of time, why does it take an infinite period of time to reach this stage. He calls this a counterquestion. Both the subject and the question are based on the assumption of Kant. Almost everyone does the same. That is, time is absolute. That is to say, time passes from the infinite past to the infinite future. Time is independent of the universe. In this context, the universe can exist or not.

Today, this picture remains in the hearts of many scientists. However, in 1915, Einstein proposed his revolutionary general theory of relativity. In this theory, space and time are no longer absolute, and are no longer the fixed background of events. On the contrary, they are dynamic forces, and the material and energy in the universe determine their shapes. They can be defined only in the universe. It makes no sense to talk about the time before the beginning of the universe. This is a bit like looking for something south of the South Pole. It is not defined.

Study of cosmic problems using empirical methods

We interpret our sensory input based on our world model.

If the universe remains essentially unchanged over time, as we generally thought before 1920s, there is no reason to block the definition of time at any early time in the past. People can always extend history to earlier times. In this sense, any so-called beginning of the universe is artificial. So it can be like this: the universe was created last year, but all the memories and physical evidence seem much older. This raises profound philosophical questions about the meaning of existence. I will adopt the so-called empirical method to deal with these problems. In this method, the idea is that we interpret our sensory input according to the world model we constructed. People cannot ask whether this model represents reality. They can only ask whether it works. First, a simple and elegant model can be used to explain a large number of observations. Second, if this model is made, it may be observed and tested, or it may be falsified with clear predictions, this model is a good one.

According to the empirical method, we can compare two models of the universe. The first model, the universe was created last year, and the other is that the universe already exists for a long time. A pair of twins were born earlier than a year ago. The cosmic model that has existed for a year can explain things like twins.

Harbo discovered that the Galaxy flew away from us.

Stars are not evenly distributed across the entire space.

On the other hand, the model created by the Universe last year cannot explain such events, so the second model is better. People cannot question whether the universe exists a year ago, or just look like that. There is no difference in the empirical methods.

In a constant universe, there is no starting point of nature. However, a fundamental change occurred in 1920s when Edvin harp began to use 100 inch of the telescope for observation on the Wilson Mountain. We found that the stars were not evenly distributed across the whole space, but instead gathered in a mass group called Galaxy.

By measuring the light from the galaxy, we can determine their velocity. He expected as many galaxy to fly to us as they would fly to us. This is expected in a time-changing universe. But what surprised him was that he found that almost all the galaxies flew away from us. In addition, the farther the galaxy leaves us, the faster the flight. The universe does not change with time, as everyone thought before. It is expanding. The distance between galaxies increases with time.

The most important discovery: The universe is expanding

Cosmic expansion is one of the most important intellectual discoveries in the 20th century or any century.

Cosmic expansion is one of the most important intellectual discoveries in the 20th century or any century. It changes the debate about whether the universe has a beginning. If the galaxy is now moving separately, they must be closer in the past. If their previous speed remains the same, then about 15 billion years ago, all the galaxies should land on the other. Is this time the beginning of the universe?

Many scientists still do not like the beginning of the universe. It seems that physics has crashed. People have to turn to the outside world for help. For convenience, they can call it God to determine how the Universe starts. Therefore, they put forward some theories. In these theories, the universe is expanding at the moment, but there is no beginning. One of them is the theory of steady state proposed by bondy, Gord and hoil in 1948.

In the theory of steady state, the idea is that, as the galaxy leaves, a new galaxy is formed from the material continuously created in the entire space as it is assumed. The universe will always exist and appear the same in all time. The final nature of this is, from the empirical perspective, a clear prediction that can be tested by observation has great advantages. In the early 1960s S, the Cambridge Radio Observatory astronomy team, led by Martin lyr, investigated weak radiation sources. These sources are evenly distributed in the sky, indicating that most of the sources are outside the Milky Way. On average, the weak source is far away.

Steady and steady state theory conflicts with observation

The weak source is more than predicted, which indicates that the source density is higher in the past.

The steady state theory predicts that the number of sources corresponds to the shape of the source intensity graph. However, observations show that there are more weak sources than predictions, which indicates that the source density is higher in the past. This is in conflict with the basic assumption that everything in the theory of steady state remains unchanged in time. For this reason, the theory of steady state is also abandoned for other reasons.

Another attempt to avoid the beginning of the universe is that it is recommended that there be an earlier contraction phase, but due to the rotation and local randomness, the material will not fall to the same point. On the contrary, different parts of the material are staggered, and the universe expands again, so the density remains limited. The two Russians lifsiz and haryankov actually claim that they prove that general contraction without strict symmetry will always cause a rebound, while the density remains limited. This result is very convenient for the dialectical materialism of Marxism-Leninism, because it avoids the insurmountable problems related to the creation of the universe. Therefore, this is an article of faith for Soviet scientists.

TV snowflake was inspired by cosmic microwave

A few percent of the snowflake seen on the screen is attributed to the microwave background.

I was a 21-year-old graduate student, and I was looking for a question to complete my doctoral thesis when lifsiz and harannikov made their claims. I don't believe what they call proof, so I started to work with Roger Penrose to develop a new mathematical method to study this problem. We prove that the Universe cannot rebound. If Einstein's general theory of relativity is correct, there is a singularity, a point with infinite density and infinite space-time curvature, where time has a beginning.

Several months after I got the first singularity result, that is, in October 1965, people had observed evidence that the universe had a very intensive beginning, that is the weak microwave background that passes through the whole space. These microwaves are the same as the ones you use, but they are much weaker than them. They can only heat pizza to 270.4 degrees Celsius, or even not freeze it, let alone bake it. In fact, you can observe the microwave. Adjust your TV to an empty channel. A few percent of the snowflake seen on the screen is attributed to the microwave background. The radiation left behind by early very hot and dense states is the only rational explanation of this background. As the universe expands, radiation continues to cool down until today we are able to see its faint remnants.

Although Peng rose and my own odd theorem predicted that the universe had a beginning, these theorems did not tell the universe how to start. The general theory of relativity equation collapsed at the singularity. In this way, Einstein's theory cannot predict how the Universe starts. It can only predict how it evolves once it starts. People may have two attitudes towards Peng rose and my results. One is that God chooses the starting method of the universe for reasons we cannot understand. This is the opinion of John Paul. At a cosmic conference in the Vatican, the Pope told delegates that it was okay to study it after the beginning of the universe. But they should not explore the beginning, because this is the time of creation, and this is the thing of God. I am glad that he did not realize that I published a paper at the meeting, just proposing how the universe started. I don't think Galileo was handed over to the religious referee's office.

The Study of the origins of the universe requires Quantum Theory

Quantum theory must be taken into account when the universe is at the flux scale.

The explanation of our results is also approved by most scientists. The results show that, in the very powerful gravitational field of the early universe, the general theory of relativity collapsed and must be replaced by a more complete theory. Because the general theory of relativity does not notice the small scale structure of matter, and the latter is restricted by the quantum theory, it is expected that this replacement will always take place. In general, it doesn't matter whether the universe is replaced because the scale of the universe is very large compared with the micro scale of the quantum theory. However, when the universe is at the flux scale, that is, one meter in the hundreds of millions of billions, the two scales become the same, and quantum theory must be considered.

To understand the origins of the universe, we must combine general relativity with quantum theory. Richard Feynman's Thought of summing history seems to be the best way to achieve this goal. Richard Feynman is a colorful character. He tapped on drums at the puttles in passadina and was also an excellent physicist at Caltech. He proposed that a system go through all possible paths or history from State A to State B.

Global Travel Certification

I have traveled around the world, and I have not fallen.

Each path or history has a certain amplitude and intensity. The probability of the system going from A to B is to add the amplitude of each path. There is a history of the moon made of Rancho. But its amplitude is very low. This is not good news for mice.

The probability of the current state of the universe can combine all the history of the ending state into this state. But how do we start with these history? This is the origin of a change. Do you need a creator to give commands, so the universe starts like this? Or is the law of science used to determine the initial conditions of the universe?

In fact, even if the history of the universe returns to an infinite past, this problem still exists. But if the universe only started 15 billion years ago, the problem would be even more urgent. Ask what will happen at the beginning of time, a bit like when people think the world is flat and ask what will happen at the edge of the world. Is the world a tablet? Does the ocean flow from its edge? I have already used this experiment to verify it. I have traveled around the world, and I have not fallen.

As we all know, when people realize that the world is not a flat, but a curved surface, what happens at the edge of the universe is solved. However, the time seems different. It seems to be separated from space. Like a track model. If it has a starting point, someone must start the train.

There is no way to oppose the beginning of the universe

The beginning of the universe is governed by the law of science.

Einstein's general theory of relativity unifies time and space into time and space. However, time is still different from space. It is like a channel, either starting or ending, or stretching out infinitely. However, James hattel and I realized that when general relativity and quantum theory are combined, in extreme circumstances, time can behave like another direction in space. This means that, like the way we get rid of the edge of the world, we can get rid of the beginning of time.

Assume that the beginning of the universe is like the south pole of the earth, and its latitude takes the role of time. The universe is in the South Pole as a starting point. With the movement to the north, the circle representing the constant latitude of the cosmic scale expands. Question what is meaningless before the beginning of the universe. Because there is nothing in the south of Antarctica.

Time, measured by latitude, has a beginning in the South Pole. However, the South Pole is very similar to other points. At least I heard this from others. I have been to Antarctica and have never been to Antarctica.

The same law of nature is established in the South Pole, just as in other places. For a long time, people have said that the beginning of the universe is the failure of normal law, so the universe should not start. Now, the beginning of the universe is restricted by the law of science, so arguments against the beginning of the universe are no longer true.

The universe expands like boiling water bubbles

The most likely history of the universe is the surface of a bubble. Many small bubbles appear and then disappear

James hattel and I developed the spontaneous creation of the universe, like bubbles in boiling water.

The idea is that the most likely history of the universe is the surface of bubbles. Many small bubbles appear and then disappear. These correspond to the tiny universe, which expands, but collapsed again when they are still at the microscopic scale. They are another possible universe. We are not very interested in them because they cannot last long enough to develop Galaxy and stars, not to mention Smart Life. However, some of these small bubbles will expand to a certain scale, so that they can safely escape the slump. They will continue to expand at an increasing rate to form the bubbles we see. They correspond to the universe that begins to expand at an increasing rate. This is the so-called inflation, just as the price increases every year.

The world record for inflation should go back to Germany after the first battle. The price increased by 10 million times during the 18-month period. However, it is insignificant compared with the inflation in the early universe. The universe has expanded by ten to 30 Power times in a much smaller time than a second. Unlike inflation, the inflation of the early universe is a very good thing. It produces a very huge and even universe, as we have observed. However, it is not completely uniform. In the sum of history, the slightly random history is almost the same as the probability of completely uniform and rule history. Therefore, the theory predicts that the early universe may be slightly uneven. These latencies cause small changes in the intensity of microwave backgrounds from different sources. The map (microwave ry) satellite has observed the microwave background and found a completely consistent change with the prediction. In this way, we know that we are on the right path.

"God is throwing a dice"

We are the product of quantum fluctuations in the universe.

The randomness in the early universe meant that the density in some areas was higher than that in other places. The gravity attraction of these additional density slows down the expansion of this region and eventually causes these regions to collapse to form Galaxy and stars. Please take a closer look at this microwave sky chart. It is the blueprint of all structures in the universe. We are the product of quantum fluctuations in the vast universe. God is throwing a dice.

Over the past century, we have made amazing progress in the field of cosmology. The general theory of relativity and the discovery of cosmic expansion have shattered the ancient images of the universe that will exist forever and will continue to exist forever. Instead, the general theory of relativity predicts that the universe and time start at the beginning of the Big Bang. It also predicts that time will end in the black hole. The discovery of cosmic microwave backgrounds and the observation of black holes support these conclusions. This is a profound change in our cosmic images and reality.

Although general relativity predicts that the universe came from a period of high curvature in the past, it cannot predict how the Universe formed from the Big Bang. In this way, general relativity itself cannot answer the core question of cosmology, why is the universe so. However, if general relativity and quantum theory are combined, it may predict how the Universe starts. It starts to expand at an increasing rate. The combination of these two theories predicts that in this period called inflation, tiny fluctuations will develop, leading to the formation of galaxies, stars, and all other structures in the universe. The observation of small non-uniformity in the cosmic microwave background completely confirms the properties of the prediction. In this way, we seem to be moving in the correct direction of understanding the origins of the universe, although there is a lot of work to do. When we precisely measure the distance between space aircraft and then detect the gravitational waves, we will open a new window of the polar universe. Gravitational Waves spread freely to us from the earliest time, and all the substances involved cannot block it. In comparison, free electrons scatter light multiple times. This scattering occurs until 0.3 million years after the electron is condensed.

Will the universe collapse again?

We are close to answering this old question: why are we here? Where do we come from?

Although we have achieved some great success, not everything has been solved. We observe that the expansion of the universe accelerates again after a long period of slowdown. This theory cannot be clearly understood. Without such understanding, we cannot determine the future of the universe. Will it continue to expand infinitely? Is inflation a natural law? Or will the Universe eventually collapse again? With the new observation results, the theoretical progress is coming soon. Cosmology is a very exciting and active discipline. We are close to answering this old question: why are we here? Where do we come from?

Thank you.

This article is copyrighted by Professor Hawking.