The phenomenon of time dilation in space for a long time agitated the minds of science fiction writers from around the world. However, the question of how much effect the movement of the astronaut at the speed of light on its biological clock, was first described in the so-called “twin paradox” in which an astronaut travels into space on a high-speed rocket, while his twin brother stays on Earth. It is considered that on return to the blue planet, an astronaut discovers his twin older, while the appearance of the space traveler will remain almost the same.
Why the speed of light slows down time?
The time dilation goes back to the special theory of relativity, which teaches us that movement in space creates changes in the flow of time. The faster you move through the three dimensions that define the physical space, the slower you move through the fourth dimension, which, in fact, represents the time. Time in this case is measured differently for the astronaut and his twin who remained on Earth. A clock in motion runs slower than the clock that we see on Earth. However, if the astronaut will move with a speed close to the speed of light, the effect is much more pronounced.
According to an article published on the portal technologyreview.comthe time dilation is not a thought experiment or a hypothetical concept — it’s real. Experiments the Havel-Keating, conducted in 1971, proved a unique opportunity to almost completely stop time in that moment, when two atomic clocks were on planes flying in opposite directions. The relative movement has had a measurable impact, creating some difference in time between two clocks. A similar phenomenon was also confirmed in other physical experiments (e.g., fast moving muon the particles are exposed longer to decay than others).
In modern science it is believed that “relativistic speeds”, which are usually between one-tenth the speed of light, somehow manifest the effects of relativity. In this case, an astronaut returning from space travel back will look much younger than their friends and family members the same age who remained on Earth. The question of how exactly he is younger it will look, will directly depend on the speed of the spacecraft.
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However, there is another point worth mentioning: time can slow down not only because of the influence of the speed of light, but also as a result of exposure to some gravitational effects. You may have seen the film Christopher Nolan “interstellar”, which shows that the proximity of a black hole is able to literally stretch the time on another planet, turning one hour on Miller’s planet in the equivalent of seven earth years.
This form of time dilation are real, which is proved in the General theory of relativity. Gravity in this case can considerably distort the fabric of space-time, causing the clock closer to the gravity source, undergo a much slower time than usual. The astronaut stranded in the vicinity of a black hole will age much later than his twin brother, who decided to stay home. This situation, perhaps, could be a great scenario for a new Hollywood blockbuster.