Today is Pi Day, a holiday that celebrates the mathematical constant π (pi). March 14th is 3/14 in month/day date format (the crazy American standard). It is celebrated on this day because pi's first 3 digits are 3.14, the common approximation of pi.
Yes, it is a real holiday. The U.S. House of Representatives supported the designation of Pi Day in 2009, but it was created in 1989 by Larry Shaw of the San Francisco Exploratorium. In the European day/month format, the fractional approximation of pi is used, 22/7. Pi Approximation Day (or European Pi Appreciation Day) is therefore celebrated on July 22nd. More info on the holiday.
|My favorite: Pumpkin Pi!|
Pi is mostly enjoyed because it is a homophone of pie, which is delicious. It is not a lie, unlike cake. Pi is used to describe the relationship between a circle's circumference and diameter, as defined by the equation π = C/d. Pi is an irrational number, essentially meaning that the digits after the decimal extend infinitely with no repetition or pattern. The current record stands at 5 trillion digits. More from the Pi article on Wikipedia.
There is also an interesting and growing movement against pi, The Tau Manifesto. They support the establishment of τ (tau), where τ = 2π. Essentially, 2π represents sine functions and shows up in a lot of equations, especially in Calculus. The use of tau would remove the need for the added calculations and such. Ultimately though, it is mostly a matter of aesthetics, and has no real fundamental mathematical change, and thus not a huge following. It's mostly just a novel concept. For now, we should all enjoy pi!
EDIT: looks like Dark Matter one this weeks vote, so I'll have a topic on that tomorrow. I am considering doing another open question post next time. Like I did the first time, where I selected 3 reader submitted questions to answer.