However, others claim that it is impossible because of causality, which says that the cause must precede the effect and any event can only have one cause. There is currently no experimental evidence to support the existence of time travel.

Albert Einstein contributed to our current understanding of time travel. His theory of relativity describes space, time, mass and gravity.

For him, time is relative. A key result of relativity is that the flow of time is not constant. Time can speed up or slow down, depending on the circumstances.

The fact that it can speed up or slow down is where the theory of time travel becomes a possibility that can have real consequences in the world.

Time moves faster when you are on speed, but for it to be noticeable, you have to move at the speed of light. To put it another way, time runs more slowly if you are in a gravitational field, such as a black hole.

In theoretical physics, black holes are hypothetical formations in space-time that connect two points in space and time. The possibility of the existence of such objects is mentioned in Einstein's General Theory of Relativity.

The problem with them comes from the fact that they have been proven to exist as a mathematical possibility, but not physically. If, however, it is assumed that such a hole could exist, then it would be microscopically small and it would be a problem for even a bacterium to pass through it, not to talk about passing of an object as big as a person.

The theory of relativity and quantum physics are not compatible with each other, but they work to explain certain aspects of our universe. For the time being, time travel remains elusive, just like the more mysterious mechanisms of the universe.