It's the biggest mystery. If the Universe were a funfair - galaxies whirling like fairground rides, streams of gas and dust strewn across the sky like bunting, people wandering through it eating hot-dogs - where did it come from?Who put it there?Science does a wonderful job explaining part of the story. It just can't do the beginning, or the end, or the meaning.It can't tell us why there is something, rather than nothing at all.And it can't tell...