I'm reading Derren Brown's Tricks of the Mind at the moment and I came across something two nights ago that I just had to investigate. If you could keep folding a sheet of newspaper over on itself, how thick would the wad of paper be after 100 folds?

Newspaper is 76 microns thick. I made a table (click on it and view it at 400% to read it!):

If the universe is 156bn light years across then the book (which quotes another, by Sam Harris) is incorrect sadly, because it states that the stack would be 'as thick as the known universe'. A few markers, if anyone's interested:

An average house = 8m high - reached after 17 folds

Troposphere = 17km high - passed after 28 folds

The Moon = 384’400km from Earth - left behind after 43 folds

Heliopause (the point at which our solar system ends) = Approx 17’000’000’000km from Earth - is passed after 58 folds

Alpha Centauri star system (the nearest star system to us) = 40’681’141’032’097km (4.3 light years) is reached after 69 folds

The edge of our galaxy (quickest route) = 236’518’261’814’520’030km (25’000 light years) - open space reached after just 82 folds

The edge of the observable universe = 737’936’976’861’302’500’000’000 (78bn light years) is not reached.