The physics of Newton and of Einstein work fine for everyday timescales such as we find on the Earth and the vast timescales of the Universe respectively. But once physicists started to think about what happens inside an atom, they realised they needed a whole new physics to explain it. Understanding what goes on at this level has led to an explosion of new technologies, These include most modern electronics and, of course, the atomic clocks that today provide the world standard of accuracy in timekeeping. Now people are predicting that in the future they will be able to exploit the odd behaviour of the quantum world to create computer processors that operate at light speed.