Humans are terrible with big numbers. The financial meltdown has reminded us that even highly numerate people can't really feel, in their bones, the vast difference between a million, a billion and a trillion: it's still shocking to be reminded that 1m seconds pass in less than 12 days, whereas 1tn seconds is equivalent to around 32,000 years. (To put it another way: if you'd spent £1m a day since Jesus was born, you still would not have spent £1tn.) Trying to be helpful, commentators will explain that, say, the £850bn spent to bail out Britain's banks would, in the form of £1 coins, stretch several times "to the moon and back". But this is worse than useless, because the distance from Earth to the moon is exactly the kind of big number we struggle to visualise. All I know is that it's a very long way, like Ullapool, except probably even farther.