## March 14

2015: Best Pi Day since the Julian calendar came into being. The first known celebration was in 1988 when Larry Shaw, a physicist at the San Francisco Exploratorium, first brought pies in to celebrate the mathematical constant π. A mathematical constant is a “special” number and there are several of them with pi being one of the most common and the only one to have a day set aside to celebrate it. Pi is the ratio of a circle’s circumference to its diameter. It is an irrational number and although 22/7 is often used mathematically, it is imprecise. 3.14 is also imprecise as the actual number goes on and on and on forever without repeating integers.

The word pi and the word pie are pronounced the same in English and pies have the added feature of usually being round. It was in this spirit that Shaw brought people together in order to march around in circles before eating fruit pies brought in for the event. The Exploratorium continues to have a Pi Day each year and the practice has spread. Some countries who do not use the mm/dd method of posting a date celebrate Pi Day on July 22 since their dd/mm method gives them 22/7 to play with.

Pi can be calculated out quite far using very sophisticated mathematical procedures. However, the number is often shortened to just the first two places after the decimal point or 3.14 making March 14 the day to celebrate. But the number is much, much longer. Another fun day was in 1592 because that was the first time since the introduction of the Julian calendar the number extended and 3.141592 was reached. But on this day, 3/14/15, at 9:26:53 the date was nine decimal places out or the first ten digits of pi. And it managed to do this twice, once in the morning and for those not using a 24 hours clock, again in the evening.

In 2009, HRES 224, a non-binding resolution from the US House of Representatives recognized March 14, 2009 as National Pi Day. In 2010, Google had a Doodle with circles and the pi symbol to celebrate. In 2014, the entire month was considered to be Pi Month since it was 3/14. Massachusetts Institute of Technology has often mailed out their acceptance letters to arrive on Pi Day since they are a math and science based institution. Beginning in 2012, they began to post acceptances (privately) online at exactly 6.28 PM, which they have called Tau Time. Albert Eagle proposed, in 1958 that τ be used as a symbol for 1/2π because π resembles two τ symbols conjoined (ττ). And τ is tau.

Fischer, the great American chess champion, famously said, ‘Chess is life.’ I would say, ‘Pi is life.’ – Daniel Tammet

I recited Pi to 22,514 decimal points in five hours and nine minutes. I was able to do this because of weeks of study, aided by the unusual synaesthesic way my mind perceives numbers as complex multidimensional coloured and textured shapes. – Daniel Tammet

Pure mathematics is, in its way, the poetry of logical ideas. – Albert Einstein

Mathematics is the art of giving the same name to different things. – Henri Poincare

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