Episode two of A Further Five Numbers, the BBC radio series presented by Simon Singh.

We all remember the story of the Persian who invented chess and who asked to be paid with 1 grain of rice on the first square, 2 on the second, 4 on the third and so on, doubling all the way to the 64th square. He bankrupted the state!

This doubling is a form of exponential growth, which appears in everything from population growth to financial inflation to the inflation theory that supposedly caused the Big Bang.