Interpretation of the multidimensional world

In other words, Xiaohong and Xiaoming each took two rulers in their hands, and for convenience, we assume that the two rulers they each held were perpendicular to each other. In this way, in fact, the two rulers in their hands constitute a two-dimensional plane, and the two rulers perpendicular to each other are like a cartesian coordinate system on this plane, one like the x-axis, one like the y-axis. Suppose that there is a small stick where the two of them live, and the two of them each use the "right angle ruler" in their hands to measure the length of the small stick, and find that the length they each measured is always different, and even if they use y^2+x^2, they still cannot get a constant amount. So what does this mean?

From the introduction of our previous chapter, we can deduce that this situation should be one of two explanations: 1, Xiaohong and Xiaoming entered the multiverse separately, the world has since split, and the length of the small wooden stick is no longer a uniform amount. 2, the small wooden stick can not only move on the two-dimensional plane constructed by the "right angle ruler", he can move in the field of higher dimensions, Xiaohong and Xiaoming use not enough rulers, they need to use more rulers, coordinate axes or dimensions to measure the length and size of this small wooden stick.

So which explanation is more reliable? Of course, do an experiment to verify it. We know that we humans realized thousands of years ago that we live in a three-dimensional space rather than a two-dimensional flat world. We asked Xiaohong and Xiaoming to each add a ruler to change the planar right angle ruler into a three-sided right-angle ruler, and changed the two-dimensional plane constructed by the "right-angle ruler" into a three-dimensional space constructed by a three-sided ruler. In this way, Xiaohong and Xiaoming each have a three-dimensional Cartesian coordinate system formed by the three axes of xyz. After extending the Pythagorean theorem to three-dimensional space, a miracle occurred, and the unchanging quantity was found. XiaoHong and Xiaoming, no matter what angle and how they measure the small wooden stick, as long as the measurement results of the xyz three rulers are calculated in the way of y^2+x^2+z^2, they will always be consistent and will not change. The answer to this question is found, and the second explanation is correct, the small wooden stick is an object moving in three dimensions, so Xiaohong and Xiaoming need to use three-dimensional coordinate axes to measure him to get a consistent result. (Here we should add that the small wooden stick in our actual life is three-dimensional, but even if it is a one-dimensional thing, for example, it is only a one-dimensional line segment, only long and not wide and engaged, as long as he can move in three-dimensional space, then we also need to use three-dimensional coordinates to measure, in order to get a unified measurement result.) )

So what does this question have to do with relativity? Let's look to special relativity, which was published in 1905, when a paper called "On the Electrodynamics of Moving Bodies" was published. At this time, the McMo experiment is already 15 years ago, Lorenz is thinking hard for his transformation, why is the same small wooden stick, Xiaohong standing to measure, and Xiaoming running to measure, the length is not the same? This phenomenon, referred to as scale shrinkage, is an important result of the Lorentz transformation. Although this phenomenon is extremely puzzling, Lorenz never doubted the correctness of his transformation formula, but he needed a physical explanation, and when most physicists believed that it was an illusion or measurement error when most physicists believed it was a movement, the length of the small wooden stick must be only a uniform value! Einstein said, "No, the shrinkage effect is really happening!" Running a small wooden stick is shorter than standing a small wooden stick! "In a word, it's really a pan of oil sprinkled with salt and exploded the flowers." What what? Can a small stick be short and long? So isn't that the opening of the multiverse world line? And the conditions for entering the parallel world are still so simple to run two steps? No wonder that at that time, everyone changed the law and shook Einstein together. But now we will certainly not make the same mistake again, because by this time we should have found that the shrinkage effect is not very similar to the question of the small red and the small wooden stick that we just answered in the previous paragraph? The same is Xiao Hong and Xiao Ming, the same with a ruler can not measure the unified length of the small wooden stick. It's just that the previous problem is that Xiaoming and Xiaohong can't measure it with two rulers, while now Xiaoming and Xiaohong can't measure it with three rulers. Before Xiaoming and Xiaohong increased the two rulers to three, they found the invariant, thus discovering the truth that the small wooden stick moves in three dimensions, so in the problem of ruler shrinkage, xiaoming and Xiaohong, do they also add a ruler, and increase our original three-dimensional space to four dimensions to find invariants?

The first person to think of this question was Einstein's physics teacher, Minkowski. This man is best at solving interesting physical phenomena with boring mathematical methods, so Einstein looked at him as a teacher very unpleasant. Similarly, Minkowski also disliked Einstein, a student with poor grades, and once said in class that Einstein was not a block physics material! But the world is full of all kinds of reversals, when Einstein's special theory of relativity came out, by Poincaré, Lorenz and other physics masters criticized, Minkowski showed great interest and took the lead in side with Einstein. He noticed that in the Lorentz transformation, in addition to the scale-down effect, there was another well-known time expansion effect, in which the moving person constantly looked at things shorter and the time slowed down. And after considering the two effects together, a miracle occurred, x2 + y2 + z2-ct2 When we combine the measurement results of these four coordinate axes (three lengths plus time multiplied by the speed of light) according to this formula, no matter how Xiaohong and Xiaoming measure them, whether they use a right angle ruler or a triangular plate, whether it is Casio or Rolex, whether Xiaohong is standing or Xiaoming running, the result of this formula is always the same, it is always the same. See what we get? We got the same answer as we did to the previous question of measuring small sticks. We added a "ruler" to the measurement of three rulers, although the appearance of this ruler is a little strange, he is a watch, but time we have never seen or touched, we have never seen what time looks like, so why don't we believe that time actually looks the same as length? What's more, the truth is right in front of us, when we merge time into the dimension as a kind of "length", we do get the fact that "only if the dimension is sufficient can we get the objective object invariants"! This is why we can't believe it.

After Minkowski discovered this conclusion, he integrated time and space together to form a new four-dimensional "space" and because this is a combination of time and space, physics calls it space-time and distinguishes it from other more bizarre high-dimensional spaces. Einstein at first scoffed at the space-time map he had created as a teacher, thinking that it was just his old-fashioned teacher who once again played his specialty, purely playing with boring mathematical word games. His teacher had slapped his face on his prejudices, and now it was Einstein's turn to pay it off, but when he began to think about the problem of the non-inertial system in general relativity, he had to admit that his teacher had indeed discovered the nature of the world that even he, the founder of the theory of relativity, had not recognized for a long time, and Minkowski had truly discovered the fourth dimension that we had not noticed. Legend has it that the eyes of insects can only see the flat world, only up and down left and back without front and back, we laugh at insects without knowing it, it turns out that we are not much smarter than insects, we actually travel in the four-dimensional world at the beginning, but in the shackles of three dimensions smug for a thousand years.