<p>Stephen Hawking described it as 'the discovery of the century, if not of all time', yet the scientists who first detected the cosmic radiation that was identified as the afterglow of the big bang had to admit that it was more by accident than intention. At first its discoverers mistook the readings for the disruption caused by the droppings of pigeons that had nested in their telescope, and yet they went on to win the Nobel prize.<br...