We often wish that we could go back in time and rectify our mistakes or go to the future and see what it turns out to be like. One thought is that time travel is certainly not possible, because if it would have been, then we would already have been visited by time travelers! However, let us not jump to conclusions and explore the question of whether time travel is possible, by going deeper into the subject.

To answer the question of whether time travel is possible, one must explore the very nature of time. So, let us question first what Time Travel is and what are the things that make time travel only a matter of fiction.

### What is Time Travel?

Time travel is, being able to go backwards or forward in time! A favorite subject of science fiction movies, the concept of time travel creates some weird contradictions and paradoxes.

Like the famous one of, what would happen if you went back in the past and accidentally killed your grandfather?

I could create a time machine and simply go back in time and give it to my old self! When was the time machine really invented then?

Many such paradoxes abound when it comes to traveling backwards in time. Let us get down to brass tacks and try to answer the question of, ‘Is time travel really possible?’

### Is Time Travel Possible or Not?

The question of whether time travel is possible can be broken in to two separate questions – ‘Is time travel into the past possible?’ and ‘Is time travel into the future possible?’. Let us try to see what theoretical physics, which is the only subject which can give us a realistic answer, says about both these cases of time travel theory.

### Is Time Travel Into the Past Possible?

Same is not the case with traveling backward in time. A major roadblock is the second law of thermodynamics about entropy. The disorder in the universe, termed as entropy, always goes on increasing. A reversal in time would mean an effect preceding a cause and entropy decreasing! It would violate the concept of causality and the law of ever-increasing entropy! That is why time travel backwards is not possible theoretically.

There are speculations about time travel backwards possible through a concept called a wormhole. It arises out of general theory of relativity, which tells us that gravity is not a force but a manifestation of curvature of space time! Matter bends space time around it! A very massive star which dies, warps the space around itself in such a fashion, that it creates a black hole.

Theoretically, this black hole could be one mouth of a worm hole, which connects two regions of space time with a passage and it is a mathematical solution of Einstein’s equations of general relativity. However, there is no way one can verify the truth of this statement, as mere mathematical validity doesn’t mean that it could exist!

### Is Time Travel to the Future Possible?

Time travel in the forward direction is indeed possible due to the concept of time dilation. When a particle travels fast, time slows down for it. So, for a particle traveling close to the speed of light, what was one second, could be ten minutes for us! This is because time is relative to speed of the particle. This phenomenon has been observed in case of a particle called a Muon, which lasts longer (than the time in which it should have decayed if stationary) when it is traveling close to the speed of light. So in a way, it has lived longer and traveled into the future! So, time travel into the future is theoretically possible!

Hope this article has clarified the scientific viewpoint about the possibility of time travel. Traveling back in time is simply unrealistic! So, if anybody asks you about whether time travel possible, you know what to say!

Source: http://goo.gl/OqMrL0

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