Hope You had a Happy Pi Day

Pi Day was march 14th (3.14) and the day seems to get a little more popuar every year. Since it fell on a Friday this time, it was the subject of a geekily delightful segment on NPR's Science Friday. Part of the segment is devoted to Pi Limericks and Pi-Ku.

I once wrote a song about pi which was comprised of singing the digits while playing an Am-G-F-E progression on the guitar. While I did this just for a lark, it became one of my most requested tunes. Still, others have composed better songs.

Pi Day originated 20 years ago from San Francisco's Exploratorium. The celebration is two-fold as 3/14 is also Einstein's birthday.

The world record for memorizing the decimal expansion of pi is held by Chao Lu of China. It took him slightly over 24 hours to recite 67,890 digits. According to the rules of the competition there can be no gaps longer than 15 seconds. So he had no meals or bathroom breaks.

The record for computing pi is held by a team led by Yasumasa Kanada who have calculated the number to 1,241,100,000,000 (1.24 trillion) digits. For comparison, you only need 39 digits to calculate the circumference of the visible universe to the precision of a hydrogen atom. 63 digits gives you Planck scale precision.

Maybe a million digits will do for you. If not, here are 70 billion. Actually, everyone's favorite way of celebrating pi day is pretty obvious.