Time travel is a fascinating and complex concept. It’s difficult to imagine something so radical, something that can generate a realm of paradoxes – what if someone traveled back in time and killed his biological father before he was conceived (bad chap this guy, but still, makes you think). The evolution of science and technology has successfully and consistently produced things which were inconceivable in the past – a couple of hundred years back, people could have laughed at the concept of talking to a person miles away with a device that could fit in their pockets. So, could time travel be a reality in the next hundred years or more? A very simple and effective (as far as I was concerned) argument to prove it would never be possible to travel across time is that – since no one from the future has traveled back in time to our times and met us, it proves that this technology, even if possible to build, will never be developed and used.

But, I recently realized things weren’t so simple. For one, the argument above only proves that time travel into the past would never become possible, one could still travel forward in time. And to make matters more complex, Professor Stephen Hawking notes that time travel might only be possible in a region of spacetime that is warped in the right way, and that if we cannot create such a region until the future, then time travelers would not be able to travel back before that date. In his lecture here, he mentions: 

“A possible way to reconcile time travel, with the fact that we don’t seem to have had any visitors from the future, would be to say that it can occur only in the future. In this view, one would say space-time in our past was fixed, because we have observed it, and seen that it is not warped enough, to allow travel into the past. On the other hand, the future is open. So we might be able to warp it enough, to allow time travel. But because we can warp space-time only in the future, we wouldn’t be able to travel back to the present time, or earlier.“

He concludes by saying – “…rapid space-travel, or travel back in time, can’t be ruled out, according to our present understanding. They would cause great logical problems, so let’s hope there’s a Chronology Protection Law, to prevent people going back, and killing our parents. But science fiction fans need not lose heart. There’s hope in string theory.“

Needless to say that I am confused. I am trying to read up more on this. If I find something interesting (and comprehendible), I’ll post it here.

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