8090's memories must have been part of the cartoon Doraemon. Our protagonist, Nobita, travels through time and space through Doraemon, returning to the past and the future, and experiencing a series of wonderful stories. When we were young, we pinned our dreams on cartoons, hoping that we could also travel in time to experience the wonderful life in the comics.
Later, when we grew up, there were more regrets in life. Whenever this happens, we always think: if only we could do it all over again, if Doraemon really existed, if we could go back to the past.
We all understand that there is no way to achieve time travel with the current technology of human beings, but many people believe that time travel is not a dream and may be realized in the future. It's just that current technology can't do it. But here today we have to pour cold water on those who have these ideas, because scientists have long confirmed that time travel does not exist, and that humanity cannot go back to the past in the future.
<h1 class="pgc-h-arrow-right" data-track="58" > time travel</h1>
People initially understand that time travel mostly comes from science fiction. Many science fiction novels set time travel as a future achievable goal, when people can use a sophisticated machine to travel through time and space. In science fiction, time travel is applied to stop conspiracies from the future or the past, and there are always good and evil sides in the story, who usually wrestle at some point in the past, and often the righteous side wins.
For example, in the movie "Terminator", robots from the future have a big war at this point in time, in which high-tech robots and high-tech weapons from the future have soared the adrenaline hormones of audiences around the world.
Literature and cinema seem to be telling people that time travel is a palpable dream, and that too much imagination about it makes more people believe in it. At the same time, the development of physics has also given time travel a certain amount of evidence, making its mysterious color a lot lighter.
In physics, time and space are better interpreted. These two concepts are abstract concepts that we use when describing the physical world in front of us, and they are actually more like units of measurement. Where time is the unit of measurement of the evolution of the world, we should say that time has passed as the process of change in the material world.
To put it simply, when describing our movement from one point to another, the concepts of space and time are used—how far we move in space, how much time we spend in time.
Based on this, people think that the space we are in is three-dimensional, that is, it has length (one-dimensional), width (two-dimensional), and depth (three-dimensional). People are the masters of three-dimensional space, and they can modify and set up three-dimensional. But then there are people who imagine higher dimensional space, and these people think that four-dimensional space has one more factor than three-dimensional space that can be fiddled with at will--time.
We can understand that lines are one-dimensional spaces and surfaces are two-dimensional spaces. We are in three-dimensional space, we can change the two-dimensional space at will, this process is like painting on a plane, we can fold and bend this plane. In ancient China, there was often a saying that a fairy in a painting would fly out of the painting, which was actually a leap from two-dimensional to three-dimensional.
So what happens when time is introduced as a puzzle that makes up four-dimensional space? If there were life in the four-dimensional space, then they would be free to fiddle with time! They can go backwards in time, or forward, a process that won't be much harder than moving an object on a plane to another! Based on this, these people certainly believe that time travel is possible, but humans want to break the shackles of three-dimensional space. And does four-dimensional space exist? I don't know, it's just a conjecture, no one has ever confirmed it.
Another theory that supports time travel comes from Einstein's theory of relativity. Physicists have found through observation that when an object is faster than the speed of light, it can return to an earlier state. The theory of relativity tells us that time travel can be made as long as it is faster than the speed of light. But what? This theory cannot be confirmed by people, because no matter how hard they try, even if they accelerate to the speed of light, they still cannot break through that speed, which is like a spell that prevents people from peeking into the deeper mysteries of the universe.
<h1 class="pgc-h-arrow-right" data-track="81" time travel > is just an illusion</h1>
Although time travel has a lot of theoretical support from people, these supports are unsubstantiated and cannot be adopted, and we cannot conclude that time travel is feasible.
But it proves that time travel is not feasible. First, time travel violates the second law of heat, the law of entropy increase. The heat is always transferred, from high temperature to low temperature, which is the process we usually cook rice, which generates heat, and then the heat is transferred to the rice. This physical law is immutable, and according to the law of entropy increase, this process is irreversible and produces useless consumption, the so-called increase in entropy.
Time travel, on the other hand, violates this law, because if you go back to the past from the future, then it proves that the time you are in has gone backwards, and in contrast, there is a process of entropy reduction. However, this universe has been confirmed that entropy reduction is impossible.
Time travel also violates the law of conservation of energy. According to the law of conservation of energy, energy can only be converted and transferred, for example, friction converts kinetic energy into heat. In fact, matter itself is a manifestation of energy. So what happens to time travel? Man itself is matter and energy, you appear out of thin air in the past and the future, does that mean that the universe at that point in time has an extra stream of material energy out of thin air? This violates the law of conservation of energy, so time travel is impossible.
Time travel violates not only many laws of physics, but also the logic of the development of things. Take, for example, the famous "grandfather paradox" that people have proposed. What is the grandfather paradox? Here's a conjecture that you can really go back in time. But you go back to the past for a purpose, you can't do nothing, like the robots in Terminator, one is to kill people, one is to protect people. Here again, a setting is given: you go back in time to kill people, who to kill? It turns out that you hate your grandfather, so you don't want this person to have that long life, you want to kill him when he was a child. You killed your grandfather in the past, and a serious paradox arose at this time. That's your grandfather died when he was a child, so where did you come from? If you exist, you can't go back in time and kill your grandfather.
According to the "butterfly effect", a small change can lead to huge consequences. Even if you go back to the past and do nothing, you will change the past universe, and if the past universe is changed, the direction of development will be different from the future universe. To solve this problem, we need to calculate a universe, a time travel more universe, then if time travel becomes true, how many universes must appear? So it's simply not possible.
<h1 class="pgc-h-arrow-right" data-track="82" > life is only once</h1>
In the movie "The Wonders of Benjamin Button", it tells a life story from old age to childhood, which is also a wonderful life. It is different from time travel, going from old age to infancy and living again, but really only once. However, we can feel some of the mystery of time travel from this story, you are not young, but back in the past, the people you once knew were still teenagers, and that feeling is not the end of a sentence.
In the same way, this movie is also telling us that time will not be reversed, no matter how bizarre life is, it will always be only once, and if it is missed, it will not be repeated.
And you who have only one life means that you have only one youth. What are you going to do with your youth this time? Spending time day after day on meaningless things? Brush videos, play games, see information without nutrition, these things are still possible to do when we are dying of old age. But many of the more important things are only done when you are young.
Life is only once, do you want to work hard for it once?