We've talked about time travel before, but the topic is time travel. Today, let's think differently. Okay, let's have our say! But before I do that, I'd like to give you a few ideas from others. It is generally believed that time travel begins with the general theory of relativity, that is, the bending of space-time caused by massive objects. The first is Gödel's scheme, which he believes exists in the Gödel universe and that there is a closed loop of time. In other words, the two points in time coincided. Gödel thinks that there are many closed loops of time in that universe, and that there is a closed loop point in the closed loops of time. And the closed-loop point is what makes time travel possible. Of course, this also means that time travelers can't choose their own points of time.

Second, there is Timpler's scheme. He said that the radius of a cylinder is infinite. When the cylinder rotates, it distorts time and space. Time travelers can travel as long as they stand next to the column.

The third is the request made by Hawking. He said that in order to achieve time travel, there must be negative energy and other conditions.

Fourth, Morris's scheme. He thinks there has to be a strange object. This singular object has to have negative energy and negative mass. Why should there be negative energy? He explained that the original direction of time was from the present to the future, and why has this direction not changed? Because the energy that time sustains in this direction is positive energy, not negative energy. And if you want to change time, whether it is to the past or the future, it objectively changes the original flow direction of time. In order to achieve this change, there must be negative energy. Our energy is dependent on objects for their existence, and the most obvious sign of the existence of objects is mass. Negative energy cannot exist on its own, it must enter the object. So, there has to be an object that can accept negative energy. In order to accommodate the presence of negative energy, the mass must be negative. Then, in a space there are black holes and strange objects. People enter the strange object from the wormhole of the black hole, and the strange object has a great repulsive force. At this point in time, there is no way for a person to come out of a strange object. Due to the repulsive force of the strange object, it will send people into the space of a past point in time. He explains very well that the essence of time travel is an alternative teleportation, or the free change of spatial position.

Liuzi Feng came to say: Who said that only large mass objects can distort space-time, I think that small-mass objects can also distort space-time. So, what are they? In fact, they are microscopic particles. This is called the extreme effect. Also derived from extreme effects is ultra-slow motion. It may be counter-intuitive. Slow speed can also change time and space, isn't it a joke? I know it's a bit of a difficult idea to understand. However, if you are white, the word extreme will not find it difficult to understand. In mathematics, both infinity and infinitesimal are a limit. And the amount that is close to them is extreme. You don't need much power for super slow movements, what you really need is control. Can you keep the speed extremely slow? It's hard, I'm afraid. It's like the human body has 100 billion neurons, and there are several that people can directly control. In fact, there is a corresponding word in sociology called personal management. Somewhat off topic. My core point is the extreme effect. The speed of light slows down time, while ultra-slow motion makes time faster.

Margarita said: I have a different point of view. Changing the time may not be as complicated as we think. I think it can be achieved with a pen, but how exactly does it work? First, put the pen back in its original position. Second, restore the position of the table at a certain moment when the pen was placed on it. Third, restore the arrangement of the air molecules at that time. I think as long as the degree of restoration is high enough, it is not impossible to change the time.

Duenias said: You have all forgotten to discuss the true meaning of time travel. I have a question, time travel is of course about time. But is it about space? That is, where exactly do people go? You would naturally say that time travel is not just about time, but of course traveling to the space where the point in time was in the past. But is it possible that time is actually an independent existence, independent of space? You can think of 2020 as the year 2080, but time is still not affected by you. This is said to be divided into two kinds of yin time. One is human time. Anyone who has read the book knows that there have been many kinds of epochs in human history, and now the use of the earth's rotation period and revolution period is to use the days and years. The second is the time of the universe. Astronomers know that there is an extremely small error between human time, i.e., chronology, and the real time of the universe. Human time is a regulation, and cosmic time is real time. So, I'm going to ask. If time travel changes time, does it change the entire universe? In other words, is there a place in the universe where there is no time? What is to be discussed here is the totality and individuality of time. If time is shared by the universe, it is indivisible. Then changing time is equal to changing. Of course, the screenwriters of science fiction movies believe that time is individual, that is, time can not be unified. About this, it still needs to be discussed.

Mizukawa smiled awkwardly: The issue discussed today is a bit big, and everyone's views are very good. I think a lot of brain cells have died, so let's take a break!