‘Time Travel’ has always fascinated the sci-fi community and countless movies and TV Series have attempted in some way to adopt topic in a sort of fantasy-ish way. Be it one of the latest box office successes, ‘Interstellar’ or long-running franchises such as ‘Star Trek’ or ‘Back to the future’ or even one of the cult TV Series – ‘Doctor Who’, the topic has been explored many times. But, as we talk about the significance of ‘Time Travel’ in Sci-fi community, the true, complex nature of the problem remains mysterious.
It all began with again, the same, ‘Einstein’s General Theory of Relativity’. The Theory of Relativity gave us the concept of Time Dilation. The Time moved at different rates for different individuals based on their speeds. This was further given a proof after the ‘Jet Experiment’ was done. Today, all satellites follow the theory. This gave rise to the talks that if time moved relatively to different observers, with a significant speed achieved, the time travel would be possible.
The ‘Time Travel’ still remains to be sci-fi phenomenon yet, scientists have proposed various theories as they always do that say theoretically it is possible. The first of which is just a corollary of the theory of relativity which says that if a person travels in a spaceship close to the speed of light when s/he will come back to earth they would have aged less than their identical twins on earth. Then it can be said that the person has traveled in future. This is also verifiable as it has been observed that the people who stay at the International space station for about 6 months age 0.005 seconds lesser than people on earth. Although this is a really insignificant time when considered moving at higher speeds this can be achieved. But the speed comparable to the speed of light has not yet been achieved so it still remains just a theory.
The person can also be said to have time traveled if s/he is exposed to an enormous gravitational field. Something like being close to a black hole. If this happens the enormous gravity of black hole will bend spacetime making people close to it age slower as compared to people on earth. Again not achievable at least not yet.
There has been a discussion on how time travel to a future is achievable but, what about the past? This puts even scientists in a bit of quandary. The time travel to the past have always been looked at skeptically by the scientists. One of the reasons for that being ‘The Grandfather Paradox’. The Grandfather paradox states that if a person manages to travel in the past and happens to kill his/her grandfather then once the grandfather is killed, his father won’t be born and neither would he which will mean he does not exist, which means he cannot kill his grandfather going in the past. But that again means his grandfather is alive and then he exists and he can go in the past, so this infinite loop exists. This is apparent reason scientists believe that going in the past is not possible as it would be a question on the phenomenon called ‘Causality’
Yet, some scientists have still tried to devise a theory which can enable us to go to the past (Theoretically). There is a concept called ‘Wormhole’. This is kind of passage between two distinct points in space where they say that the space-time folds. Although scientists have not found any wormholes they believe that wormholes can be built in a laboratory. Again, theoretically. They believe that if there are physical particles having zero or negative mass which quantum physics says is possible to have, then using those a wormhole can be designed. So basically this works like somehow you manage to design a wormhole actually two of them, then you keep one wormhole on earth and other you move at close to speed of light, Which will cause the two wormholes to age differently. then once you enter the wormhole on earth you can go in past as the other wormhole has not aged that much. I know, hard to believe but that’s the theory.
The scientists are striving hard to have some explanation of time traveling and to make some sense of it. As for now the concept only remains possible in theories. But, you never know what can we have in the future. But one thing is for sure, the time travel in real life is going to be a hell lot different from that in the movies. For now, all we need to do is enjoy the sci-fi genre time travels and just keep in mind, if, by any chance you happen to travel in the past, please try not to kill your grandfather.