First post, by Kerr Avon
I just thought that this was interesting, you might not agree. You know how you can't fold a piece of paper in half more than seven times? If you don't know this, then try it, no matter how big or small the paper, fold it in half, then (without unfolding it, obviously) fold it in half again, then again, and so on, each time the surface area of the paper is being halved since you're folding the paper over itself. And after seven folds you can't fold it any more.
I was reading the book Q.I. General Ignorance - The Noticeably Stouter Edition (based on the great TV series)
"If it were possible to fold a very large piece of paper of standard thickness without restriction, because the thickness of the paper would double each time it was folded, after just fifty-one folds you would have a tower of paper more than 100 million miles high – tall enough to reach from here to the sun."
which amazed me, so I wondered if it were true. And it is (I've checked several other amazing facts from Q.I. and they've always turned out to be true). If you say that a sheet of paper is 1 millimetre thick (which it isn't, of course, but it keeps the maths simple), then the first fold of paper makes the paper 2mm thick. Then raise the 2 by 50 (two to the power of fifty) to simulate the other fifty folds, and you get (thanks to the Windows calculator)
1,125,899,906,842,624 millimetres. That works out to
699,601,767 miles (thanks to Google converter). 699 million miles! Even if the paper is only one fifth of a millimetre thick, then if you fold it fifty-one times you'd get 138 million miles high!