If you thought that billiards was a harmless game to play in the pub, think again. It's a breeding ground for chaos!

One thing that makes TV game shows fun to watch is that there's usually an element of luck involved. But how (un)lucky is (un)lucky? We look at the probabilities of two popular examples.

Why does time have a direction?

Like spirals and flowers? Then you'll love polar coordinates and the pretty pictures they allow you to draw!

The early 1950s were an experimental gold mine for physicists, with new particles produced in accelerators almost every week. Yet the strong nuclear force that acted between them defied theoretical description, sending physicists on a long and arduous journey that culminated in several Nobel prizes and the exotic concept of "asymptotic freedom".

By the 1970s physicists had successfully tamed three of the fundamental forces using a sophisticated construct called quantum field theory. The trouble was that the framework seemed to fall apart when you looked at very high or very low energy scales. So how could these be thought of as valid theories? It's a question physicists are still grappling with today.