You Really Only Need to Know 39 Digits of Pi [VIDEO]By: Josh Wolford - February 21, 2013
Pi has currently been calculated to over 10 trillion (10^13) digits. But really, 39 is all you need, as the following video demonstrates.
“You only need 39 digits of pi to be able to measure the circumference of the observable universe within the width of one hydrogen atom.”
Whoa.[Numberphile via Gizmodo]