"Space," says the introduction to The Hitchhiker's Guide, "is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is." A-a-and so on. It also says that if you hold a lungful of air, you can survive in the total vacuum of space for about 30 seconds. But with space being really big and all, the chances of being picked up within that time are 22,079,460,347 to one against. Strangely, this is also the telephone number of an Islington flat where Arthur Dent went to a fancy dress party, and met a very nice young woman whom he totally blew it with. Though the planet Earth, the Islington flat and the telephone have all now been demolished, it is comforting to reflect that they are all, in some small way, commemorated by the fact that 29 seconds later, Arthur and Ford were, in fact, rescued.