Can Time Travel? Most scientists give a negative answer to this question, but according to Einstein and quantum theory, it is.
Imagine: you watch dinosaurs frolic on Red Square, meet Columbus together with the indigenous population of America, place bets on knightly tournaments in medieval England, or follow the course of the Battle of Austerlitz. Would you be able to remain an indifferent observer of the slave market or save the lives of Martin Luther King and Franz Ferdinand? Many films have been made about time travel, tons of books have been written, but what does science say about it? Are they possible?
Casting aside doubts and skepticism
We can say that we are constantly witnessing such travels. Every second, a dozen tiny cosmic particles called muons permeate us. They are too small to feel them, but they often cause damage that the body has to repair. Thus, astronauts in outer space can die from too much dose of cosmic radiation, which causes radiation sickness.
Muons are a kind of "fragments" formed when particles of the Sun and stars collide with the atmosphere 20 km above the Earth. Traveling at the speed of light, approximately 300,000 kilometers per second, they reach a person in seven millionths of a second. The only problem is that muons have a lifespan of only two millionths of a second and, in theory, they shouldn't reach the Earth's surface. But, according to Einstein, muons travel in time to get to us.
According to the theory of relativity, our life will become slower if we travel at a speed close to the speed of light. We will also live longer if we find ourselves in a more intense gravitational field. Einstein argued that it was theoretically possible to slow down the passage of time for oneself, leave the Earth and return to meet with his grandchildren or even great-grandchildren, but did not give a guarantee of return. However, physicist Stephen Hawking believes that one cannot travel into the past, since one can accidentally kill one's own grandmother even before the mother or father is born, and thus make it impossible to be born, and, consequently, to return. That is, the return is impossible with the generally accepted model of the world. But some scientists believe that there are an infinite number of parallel worlds in the universe. With such a structure, having fallen into the past and killing his own grandmother, a person will simply create an offshoot in time, a parallel world in which he is no longer a part of the future.
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Through space and time
If we dive into the tiny world of nuclear particles, we see that they, like muons, are capable of transcending space and time. There can be an unusual connection between such particles, causing strange quantum effects. If two particles appeared for the same reason at the same time, they are most likely related to each other. The strangeness of this connection is that each particle of the pair will immediately know what is happening to the other, even while in another corner of the universe! So, if one electron from such a pair of particles with different features of rotation is on Earth, and the other is lost in outer space, we will find out the speed of its rotation by measuring that of the “local” electron. Somehow, information between them is transmitted instantly. This is an instant journey through the universe, and no one knows how this is possible. There may be more than three dimensions through which electrons "Communicate" with each other. And these measurements can be used for time travel.
Much the same thing happened when, after the big bang, the universe suddenly began to expand at a speed exceeding the speed of light. Maybe this was made possible by other dimensions, but so far no one knows for sure. We only know that there are many unexplained facts that indicate the possibility of time travel. But what can we do now? Wait for a tourist from the future to come and teach us how to make such trips. Looking for more advanced civilizations, for which such travel is a common thing, and enter into correspondence with them? But since such communication will take at least decades, it is best to seek the answer in the field of physics. Then one day it will be possible to make a leap into the fifth dimension and take pictures of dinosaurs frolicking at the walls of the Kremlin.