# Happy Pi Day!

Pi Day!

As you might know, March 13th is $\pi$ Day.  If you’re obsessive about these things, the $\pi$ Second is March 14 at 1:59:26 p.m.   Today is a great day to eat a piece of pie (of course, every day is a great day to eat pie!).  Or, even better, you could tackle the pie themed Problem of the Month!

If you’re interested in $\pi$ Day related stuff, you can also check out the Pie Day website which has T-shirts, the $\pi$ Clock, and other cool stuff.

Some Fun Facts about $\pi$:

1. There is the famous Indiana Pi Bill which was proposed in 1897 and among other things supposedly gave a way to square the circle despite the fact that mathematicians had proven it was impossible to square the circle in 1882.  It also proposed that $\pi = 3.2.$
2. Everybody knows that the series $\sum_{n>0} \frac{1}{n^2}$ converges, but in fact it Euler showed in 1735 that it converges to $\pi ^{2}/6$!
3. Most people also know that $\pi$ is irrational, some know it is transcendental, but nobody knows about the distribution of the digits 0,1,2, 3, 4, 5, 6, 7, 8, 9 in $\pi$.  That is, experimental evidence suggests that each digit appears 1/10 of the time, but nobody knows how to prove it!  In fact nobody even knows if all the digits occur infinitely often!
4. $\Pi$ has been calculated to a trillion digits and the Guinness-recognized record for remembered digits of π is 67,890 digits, held by Lu Chao, a 24-year-old graduate student from China.  But if you’d like to compute the circumference of any circle that fits in the observable universe to a precision comparable to the size of a hydrogen atom, then a mere 39 decimal places is sufficient!
5. It’s not just a math constant, $\pi$ appears in nature.  For example in Einstein’s Field Equations.

If you have some spare room in your brain, you can certainly fill it with the digits of $\pi$.  The secret, apparently, is the art of Piphilology:  memorizing a poem/story/etc. where each word has the number of letters equal to the next digit of $\pi$.  For example,

How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics.

Or, if you’re hardcore you can spend spring break memorizing the Cadaeic Cadenza!

Failure is just success rounded down.