We have seen a lot of science fiction movies where they get on a machine to travel through time. Those sort of things happen only in movies, or is it? The fascination with time travel started when the movie Back to the future got released and ever since the idea of DeLorean which acts as a time machine that could allow us to travel to the past and the future always seem to spellbind us. Scientists argue that the very concept of travelling through time is not possible. So is that all just a concept or is time travel actually possible?
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| Time Machine |
Well, according to the theory of Relativity, the faster you travel, the slower you experience time. Einstein was the first to believe that time is not a constant, whereas it slows down as you go faster through space. So the bending of time is actually possible. To understand time travel, we must understand what time really is.
What is time?
We all assume that time is constant, but it is not. Einstein proved the existence of the fourth dimension (The Time). We exist in the three-dimension, where we can move in all three dimensions easily, whereas Einstein told the time is just an illusion and it is relative. We assumed that time only can move forward.
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| The Flow of time |
But Einstein thought otherwise and he proposed the Theory of Relativity in 1905. Space and time were considered to be a unified entity and he proposed that bending was time was possible. He stated the nothing in the universe can travel faster than the speed of light. So if the bending of time is possible, then there must be a way to travel through time, right?
How does time travel work?
The idea of time travel may not be the one that we see in the movies, whereas it might be a one-way ticket. Time moves slowly as you move faster through space. So the closer we are to the centre of Earth, the more we are accelerated by the gravity of the planet and so the time around us slows down.
So the farther the object gets away from Earth, the faster the time becomes. This effect can actually be felt by the astronauts on the International Space Station (ISS) and the satellites revolving around the Earth. The highly precise clocks onboard the Satellites can gain an average of 38 microseconds a day due to this theory.
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| Time Travel |
This theory is well explained in the movie Interstellar, where the protagonists land on a planet that has an extreme gravitation field because of the presence of a black hole near it. Due to the presence of the black hole, the crew landed on the planet experiences intense gravity and so the acceleration due to gravity is huge. And so the crew on the planet experiences time dilation. Consequently, one hour on the planet becomes 7 years on Earth. Voila! They did travel time through time.
Can Black holes make time travel possible?
So the Black holes are a region in space where the gravity is so strong that even light can't escape it and so we can't see the black holes in space.
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| Black Hole |
Going near the Black hole could cause time dilation and you might be experiencing time gradually, but there is a high chance of you getting sucked into the black hole and if you suck to the point of no return, you would be stretched and 'spaghettified' by the gravity of the Black hole. So do you still want to take that risk?
Even if you survive that and travel to the future, you would be stuck in the future as there is no way to use time dilation to travel to the past. So even if we risk it, it would only be a one-way trip.
Is Wormhole the solution to time travel?
The Wormhole might also be the solution to time travel as it can act as a bridge between two different space-time so that we don't have to cover the distance between two different space-time. The wormholes are also called an Einstein-Rosen Bridge. Although we haven't seen any wormhole in space. This is purely a theoretical concept and in fact, we haven't even proven the existence of wormholes yet. But it might be the best time machine we got.
Grandfather paradox:
It is a greatly spoken time travel paradox. The paradox is basically that if you go back in time to kill your grandfather before he had any children, it would create a paradox because if he didn't have any children that would make your own birth an impossibility. So if the possibility of time travel exists, it must somehow avoid the contradiction of the Grandfather paradox.
Why Travelling to the Past is a Bad Idea?
Even if the wild fascination of time travel becomes possible, we may alter the reality because of the butterfly effect. The small disturbances you cause in the past might modify the present. If you understand the grandfather paradox, it is a misunderstanding that you can have enough time to kill him, let alone having to see him.
But Actually, some theories say that time travel is like opening a portal to a multiverse. So the changes you make in the past doesn't affect your past, whereas it is actually affecting the future of another dimension. Yeah! I know Time travel and its paradox are definitely confusing.
Conclusion
Even as the idea of Time Travel sounds intriguing, we still haven't made any serious progress in Time Travel. But the theoretical possibility of this idea lives on, we are limit only by our technology now. We as humans might make a great leap in the field of quantum mechanics which could help us to travel to time. It is just a matter of time. Pun intended! Although the hopping into a time machine and travelling through time is not possible yet. We still experience time dilation in our life.
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