A piece of paper folded 103 times is as thick as the Universe

Folding paper in half over and over again is a whole lot harder than it sounds. The current record is 12 times, performed over a decade ago by American high school student, Britney Gallivan. Before she managed her twelfth fold, the record was just seven folds, and it was believed to be mathematically impossible to get any higher than that.

The phenomenon is based on the exponential growth of the thickness of a sheet of paper when it’s folded in half - each time its thickness doubles and requires more and more energy to fold it. Dr Karl Kruszelnicki has done some awesome maths over at ABC Science Online with a standard A4 sheet of paper, measuring about 300 mm long and 0.05 mm thick:

"The first time you fold it in half, it becomes 150 mm long and 0.1 mm thick. The second fold takes it to 75 mm long and 0.2 mm thick. By the 8th fold (if you can get there), you have a blob of paper 1.25 mm long, but 12.8 mm thick. It's now thicker than it is long, and, if you're trying to bend it, seems to have the structural integrity of steel."

But what if you kept going? Nikola Slavkovic has run through the maths of the Paper Folding Problem on his YouTube channel and has come up with this: If you fold a piece of 0.099mm-thick paper 103 times, the thickness of the paper will be larger than the observable Universe: 93 billion light-years, to be exact.

This of course assumes you can find a piece of paper larger enough and you have enough energy to fold it.

"Folding the paper in half a third time will get you about the thickness of a nail.
10 folds and the paper will be about the width of a hand.
23 folds will get you to one kilometre.
30 folds will get you to space. Your paper will be now 100km high.
Keep folding it. 42 folds will get you to the Moon.
Now fast forward to 81 folds and your paper will be 127,786 light-years, almost as thick as the Andromeda Galaxy.
And finally, at 103 folds, you will get outside of the observable Universe, which is estimated at 93 billion light-years in diameters."

Now let's all take a moment to appreciate how amazing maths is.