BBC Time Series (5 Clips) COSMIC TIME

Throughout history, one thing has never changed – time. It is something we rely on to plan our lives, and it is consistent, regular and ceaseless. But is it? High in the Alps, Michio encounters a mystery – tiny particles called muons which shouldn’t exist. They don’t last long enough to be detected on Earth – and yet here they are. The answer to this mystery lies in one of the greatest discoveries of all time – Einstein’s theory of relativity. The faster you travel, the slower time ticks. So time is not fixed at all.