The topic of time travel is one of the most popular in science fiction, as it gives authors almost limitless scope for imagination. However, is it possible to truly travel to the past or the future from the point of view of modern science?
The easiest way to travel to the future
The most plausible way to travel to the future is perhaps cryonics. Cryogenic conservation allows you to freeze a dead person or his brain in the hope that someday, perhaps hundreds or even thousands of years from now, our descendants will find a way to revive such remains. Today, for a large sum, you can already bequeath your body or the main organ of the central nervous system for cryopreservation. However, no one knows for sure if the people of the future will be able to bring us back to life in this way. At least today, tissues frozen to sub-zero temperatures are considered irreversibly damaged.
Can you travel back in time?
Modern scholars believe that many of the themes that science fiction writers touch upon are theoretically possible or will certainly come true in the future. These people of science include perfect artificial intelligence, intergalactic travel, encounters with aliens, a significant increase in the duration of human life, and so on. Nevertheless, the possibility of travel back in time is almost irrevocably rejected by experts.
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Scientists tell us that physics and other aspects of nature obey the so-called law of cause and effect. First comes the cause, then the effect, and nothing else. If someone managed to travel back in time, they would violate this law, causing a paradox that the Universe cannot allow.
For example, in pursuit of a noble goal, you decided to go to the past and kill Hitler before he commits his anti-human crimes. Let's say you succeed. However, if Hitler is dead and World War II is averted, you will not go back in the future to eliminate the Fuhrer. This is the paradox of time travel.
True, some theorists believe that the universe could cope with such a problem. In their opinion, if we assume that someone will still go to the past and kill Hitler in a timely manner, then our reality will be divided into two parallel realities. In one of them, World War II will occur, in the second it will not, which, of course, will transform the world in geopolitical terms. Who knows: maybe such changes in reality have already been made, and we are now living either in a "good" or in a "bad" timeline, depending on what these adjustments were.
A loophole for traveling back in time
It should be noted that there is one small, very tiny loophole for traveling back in time. We are talking about wormholes, or wormholes - hypothetical "tunnels" in space and time. The existence of such anomalies does not contradict Einstein's theory of relativity and other generally accepted ideas about reality.
The renowned British theoretical physicist Stephen Hawking is one of the scientists who popularized the theory of wormholes. The British researcher is convinced that wormholes can allow humans to travel through space and time, going back in time and covering distances of millions of light years. According to Hawking's assumptions, the entire universe is riddled with wormholes. However, it is not yet possible to use them.
The fact is that wormholes, presumably, exist only in the so-called "quantum foam" and are smaller than atoms. Obviously, a person simply cannot fit into such a hole. Nevertheless, the opinion is put forward that the technologies of the future will be able to allow scientists to create a wormhole artificially and enlarge it by a factor of quadrillion, having the opportunity to travel to other times and places of the universe.
Astronauts make minor journeys into the future
Yes it is. For example, the Russian cosmonaut Sergei Krikalev, who spent eight hundred and three days in orbit in total, fell into the future by about one two hundredth of a second.
This is caused by the expansion of time, a gravitational phenomenon described by Einstein in his theory of relativity. The faster an object moves, the slower it ages relative to stationary objects. In other words, as a result of this trip, a person driving a car will be somewhat younger than an individual sitting on a bench at the same time. However, it is so insignificant that it will be imperceptible even by the standards of the Universe.
The International Space Station is known to travel in space at a speed of nearly thirty thousand kilometers per hour. If it covered a billion two hundred kilometers per hour, then an astronaut who spent a year in orbit would return to Earth and see that more than two centuries have passed there.
Of course, this is still a fantasy, but American scientists in recent years started talking about the fact that they began to develop an engine that would allow spaceships to move at a speed close to the speed of light. Thus, people on board such an intergalactic ship will be able, in theory, to return to Earth much younger than their earthly children or even grandchildren.