The internet changed our perception of time: We're looking at the past on our video screens, and it's just as clear as something in the present, making it feel like an unending present.

Time travel is also a powerful way to imagine what the future might bring. Time travel allows us to explore the consequences of our worst tendencies.

Over 50 scientific papers are published a year on the idea of time travel. Even though they will probably never solve the problem of time travel, they still love to talk about wormholes and dark matter.

Einstein, with his theory of relativity, spoke of time as a fourth dimension. After that, Hermann Minkowski said that we should talk about space and time as a union of the two, spacetime, where the future already exists, and the past still exists. Today we're comfortable talking about time as a fourth dimension.

One of the reasons we continue to be so fascinated with time travel is that we can go back and undo our mistakes. Then we also have a curiosity about the future.

However, every time travel story is about death. The idea of time travel is ultimately about our desire to defeat death.