From physicist Michio Kaku's string theory to science fiction, we know what multiple dimensions and parallel universes look like. The idea of parallel universes has existed for a while now. Theory comes first, and then once technology catches up, the theories turn into reality. But to build the time machine in the first place, we would probably need rare cosmic material and technology that we do not have access to, at present. Even if a physicist does prove time travel to be real based on a genius equation, we would never really know unless we can build a machine capable of traveling through time based on that equation. In short, there are two big challenges in proving whether it is possible or not. Also read: Space triumph! Photos of 4 brown dwarfs taken by group of researchers The challenges with time travel But if you look at the theory of relativity, it does offer a small window into whether time travel is really possible or not. In short, time travel is the most fascinating yet confusing puzzle that exists.

Even Albert Einstein, the great physician, took up the challenge of understanding how time works and wrote his general theory of relativity around it. From popular media to scientific journals, many have tried their hands at understanding and explaining this problem in their own ways. And it also remains one of the biggest mysteries for physicists to solve. Is time travel possible? We all have wondered this at least once in our life.

Kaku time travel