A time paradox usually refers to the logical possibility of deriving contradictory conclusions due to time travel or time travel, while assuming that two or more premises cannot be established at the same time, which is a common feature of all paradox problems. Pen × fun × Pavilion www. ｂｉｑｕｇｅ。 ｉｎｆｏ

The paradox of time was first mentioned in science fiction. The necessary premise of this paradox is that human beings can control the "fourth dimension" after the three-dimensional space, time, at will, and can travel to the past or the future.

As far as serious physical theories are concerned, there is indeed the possibility of changing time without violating the known laws of physics. But more of a science fantasy. In order to solve the "time paradox", there are also various hypotheses, such as the more popular "parallel universe" hypothesis, which holds that there are many similar "clone worlds" in our world in the universe, and when someone goes back to the past, he enters another parallel world (i.e., the world in which the future has been changed by his actions)[2] or it may create many other side worlds in the main world, and the side world collapses and disappears due to a certain moment (maybe the moment you go back to the past), It may also be the same as it was, but the laws and circumstances of each world may not be the same.

A went back in time and killed A's grandfather before A's father was born. Since a's grandfather is dead, there will be no afather; Without a father, there would be no a. Since A does not exist, it is impossible to go back in time and kill A's grandfather.

Time is a developing thread, and there is a cause and effect relationship in everything you do. According to Example 1, it makes sense to go back in time and kill your grandfather for the first time. After you succeed in killing your grandfather, the moment your grandfather dies, anything related to your grandfather will change, and the people your grandfather knew, and the friends or relatives of people who knew your grandfather will not exist, then according to the butterfly effect, the world will also disappear because you killed your grandfather.

Someone arrives in the future and learns that an unfortunate outcome will happen. He returns to reality and takes actions that avoid leading to the outcome, and the result B happens. Then it is impossible for him to know that Outcome A does not happen in the future.

A goes back in time and tries to avoid B's car accident, but it was A's advice that made B insist on driving, and then the car accident occurred. This paradox is similar to self-fulfilling prophecy.

A drank a cup of poisonous coffee, and over time, the poison in the coffee worked, he sent a message to his past self to tell his past self not to drink that cup of coffee, you didn't drink that cup of coffee in the past, so the question is, since you didn't drink that cup of coffee, how did you send that message?

After the birth of the paradox of time, there was a difficult problem of great interest --- the twin paradox. A pair of twins, A and B, A is on Earth, and B goes on an interstellar trip on a rocket and returns to Earth after a long time. Einstein asserted from the theory of relativity that the two experienced different times and that B would be younger than A when they reunited. Many people have questions, thinking that A is watching B in sports, and B is watching A in sports, why can't A be younger than B? Since the earth can be approximated as an inertial frame, B has to undergo acceleration and deceleration processes, and is a reference frame of variable acceleration motion, which is very complicated to discuss, so this problem that Einstein has already discussed clearly is mistaken by many people for the theory of relativity as a self-contradictory theory. It would be much easier to discuss this problem with the concepts of space-time maps and world lines, but it would require a lot of mathematical knowledge and formulas. Here are just words to describe the simplest of situations. However, it is not possible to go into more detail in words alone, so if you are interested, please refer to some books on relativity. We conclude that B is younger than A in any frame of reference.

For the sake of simplification, the rocket accelerates to sub-light speed for a very short time, flies for a short time, makes a U-turn for a very short time, flies for a short time, and decelerates to meet the Earth for a very short time. The purpose of this is to omit the effects of acceleration and deceleration. It is well discussed in the terrestrial frame that the rocket is always a moving clock, and B is younger than A at the time of reunion. In the rocket frame of reference, the earth is the moving clock in the process of constant velocity, and the time process is slower than that in the rocket, but the most critical place is the process of the rocket turning around. In the process of making a U-turn, the Earth passes half a circle from a very short distance behind the rocket to a very short distance in front of the rocket. This is a "faster-than-light" process. It's just that this superluminal speed does not contradict the theory of relativity, and this "superluminal speed" does not transmit any information, and it is not superluminal in the true sense of the word. Without this U-turn process, the rocket and the Earth would not have been able to meet, and since there is no uniform time for the different frames of reference, it is impossible to compare their ages, only when they meet. After the rocket makes a U-turn, B cannot directly accept A's message because it takes time for the information to be transmitted. The actual process that b sees is that in the U-turn, the earth's time schedule is suddenly accelerated. In B's view, A is younger than B, and then ages rapidly when he turns around, and when he returns, A ages slower than himself. When they reunited, they were still younger than A. That is, there is no logical contradiction in the theory of relativity.

If time travel is possible, why haven't we been surrounded by time travelers from the world of the future? The subtext of the question is that time travelers are not coming around us, most likely because time travel has never been achieved in the entire river of time.

Scientists in the last days did not regard such a question as a serious theoretical crunch of the time machine. Still, his question has some physicists pondered, and they found a possible answer: that the theoretical models that we currently know to make it possible to achieve time travel have a common feature that is likely to be universal, that is, it does not allow time travelers to go back to the time before the existence of time machines.

Now that Lin Feng has solved the crisis of the dead world, all that remains is to find another base to hide, that is to say, there was a phenomenon of space distortion a long time ago, and the previous Naia believers used space distortion to travel to the present time to destroy.

Although Lin Feng had seen the time paradox in a scientific magazine in his supermarket, he still couldn't figure it out now, maybe this was a bottleneck point of time energy, when Lin Feng communicated the order and correctness of time travel, his time ability would be greatly improved.

When he thought about it again, Lin Feng regretted one thing, if he could get Kunajee's energy, would he be able to get the ability to travel through space from him? (To be continued.) )