What are Hawking's academic thoughts?

1, time machine

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, and the required conditions included 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.

As for the key point of time machine, Hawking emphasized the so-called "four-dimensional space", which scientists named "wormhole". Hawking emphasized that the "wormhole" is around us, but it is too small to be seen by the naked eye. They exist between space and time.

He pointed out that everything in the universe is neither flat nor real. Close observation shows that all objects have holes or folds, which is a basic physical law and applies to time. Time also has tiny cracks, wrinkles and gaps. The space smaller than molecules and atoms is named "quantum bubble", and "wormhole" exists in it.

Hawking pointed out that in theory, just visiting or "wormholes" can't take people to other planets. If the two ends of wormholes are in the same position and separated by time instead of distance, then spacecraft can fly in and out, still close to the earth, and just enter the so-called "distant past". Because in the four-dimensional space, 10 minutes may be n hours. However, Hawking warned against going back to see history in a time machine.

Stephen william hawking said that if scientists can build a spacecraft with a speed close to the speed of light, the time of the spacecraft in the cabin will inevitably slow down, because it cannot violate the law that the speed of light is the maximum speed limit. Then flying for a week is equivalent to being on the ground 100 years, which is equivalent to flying into the future.

Hawking takes the artificial satellite as an example, which means that when the satellite is in orbit, the time on the satellite is slightly faster than the time on the ground because it is less affected by the gravity of the earth. Hawking thus imagined a large-scale extremely fast spacecraft, which can accelerate to 97,000 kilometers per hour in 1 second, and accelerate to 99.99% of the speed of light in six years, which is 2000 times faster than Apollo 10, the fastest spacecraft in history. The passengers on the ship are flying to the future in disguise and making a veritable time travel.

Even in space, everything has the length of time, and roaming in time means crossing the "4-dimensional space".

Hawking pointed out that, for example, driving in a straight line is equivalent to driving in "1 degree space", while turning left or right is equivalent to increasing "2-degree space". As for walking back and forth on the Panshan Highway, it is equivalent to entering a "three-dimensional space". Crossing is just a visit, that is, entering the "4-dimensional space."

2. Alien theory

Stephen Hawking said in the documentary "Follow Stephen Hawking into the Universe" broadcast by the American Discovery Channel 20 10 on April 25th that aliens are very likely to exist, but human beings should not take the initiative to look for them, and should make every effort to avoid contact with them to avoid the attack of the dark forest! (Theory mentioned in Liu's Three-body)

Hawking believes that it is "a bit too risky" for humans to actively seek contact with aliens, given that aliens may plunder the earth's resources and then leave. "If aliens visit us, I think the result may be similar to that when Christopher Columbus set foot on the American continent. This is not a good thing for the local Indians. "

3. Interstellar migration

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 little by little. Humans can't put all their eggs in one basket, so they can't bet on one planet. "

4. High dimensional space

According to M theory (a superstring theory) put forward in 1990s, the universe is eleven-dimensional, and consists of vibration planes. In Einstein's view, the universe has only four dimensions (three-dimensional space and one-dimensional time), while modern physics believes that there are seven dimensions that we can't see.

How do scientists explain the difference between the dimensions we know and those that may exist but don't know? They made an analogy: an ant walks on a piece of paper, and it can only go right or left, forward or backward. For it, high and low are meaningless, that is to say, three-dimensional space exists and is not recognized by ants. Similarly, our world is made up of four-dimensional data (three spatial dimensions and one time dimension), and we don't know all other dimensions.

According to physicists, there should be seven more dimensions. Although there are so many dimensions, these dimensions are invisible and rolled together by themselves, which is called compressed dimension. To understand this view, let's take ants as an example and expand our imagination. We can imagine rolling up the paper on which ants walk until it is rolled into a cylinder. If ants walk along the paper wall, they will finally return to the starting point, which is an example of compressed dimension. If you can take it away along the famous Mobius, the above phenomenon will also happen. Of course, it is three-dimensional, but if you follow it, you will always return to the starting point. Mobius belt is compressed from the perspective of dimension. According to physics, it has three dimensions, but whoever walks on it can only be regarded as one. It's a bit like the person on the left: up or down, but never ending. If the ants don't walk along the curved wall of the paper tube, they will never return to the original starting point. This is an example of two dimensions (or the kind of dimensions we perceive). Go straight along it, and you can't go back to the original starting point.

Step 5 predict

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. He also said, "If human beings want to extend their existence by 654.38+0 million years, they must go to places they have never been before without fear." [ 12]?