Time travel is every friend's dream. Many friends made wrong choices when they were young, such as failing to study hard and being admitted to the ideal university, being too rebellious in high school and quarreling with their families frequently. These are all things we regret, so everyone hopes to have one? Time machine? Is it really feasible to travel back to the past and in the future? There is a famous theory in the scientific community? Grandfather paradox? If we cross over and kill our grandfather, maybe we will never appear again.

killing one's grandfather

Time is a fixed development line, and there is a certain connection between the appearance and disappearance of everyone on this line. According to the example put forward by the grandfather paradox, when we go back to kill our grandfather, the moment our grandfather dies, we will disappear with the change of time, and grandfather and his good friends will no longer exist. According to the famous butterfly effect theory, once grandfather disappears from the earth, you and your own father will not appear, changing the universe.

Method of crossing

In the scientific field, it seems more feasible to cross the future than to go back to the past. There are two ways to cross the future. For example, when our speed reaches a certain stage, according to Einstein's theory of relativity, if one object moves too fast and the other object is in a relatively static state, its time will pass too slowly. It is like we have a twin brother, and at the same time, after being born on the earth, you, as the elder brother, will be born.

My younger brother has been living an ordinary life on earth, so what will happen to you two in 3 years? After 3 years, my brother is still only 3 years old, but you have already sat in the spaceship, which will slow down your time. When my brother is 3 years old, you are only 15 years old. This effect is called in the scientific community? Clock slow effect? In fact, this theory has been confirmed and some scientists have done corresponding experiments.

the second way to cross into the future: successfully crossing the black hole, influenced by the gravity of the black hole itself, the moving speed near the black hole can exceed the speed of light, even the speed of light can't escape from the edge of the black hole, so things around the edge of the black hole will slow down, and we can cross to some extent, but according to the current technology of human beings, we can't create a superluminal flying machine.