The more you think about it, the more complex time travel seems! This video explains a key paradox that is one of the main reasons for this.

John Searle's thought experiment, called "The Chinese Room," presents an argument against the idea that computers could ever be truly intelligent.

If a hotel with an infinite number of rooms has an infinite number of guests, how could it free up space when new guests arrive? Hilbert's “Grand Hotel” paradox has fascinated mathematicians, physicists, philosophers, and theologians, as it encourages another way of thinking about the notion of infinity.

How can one brother travel into space and return younger than his twin? In just sixty seconds, a startling side effect of Einstein’s Theory of Relativity is explained to us.

Schrodinger’s hypothetical experiment involved putting an unfortunate cat into a box with a Geiger counter and a vial of deadly poison. Until the box was opened, the cat could be said to be alive, or dead… or possibly in both of these states simultaneously.