Happy Pi Day, math lovers

It's 3.14, and that means it's time for the official Pi Day celebrations to begin.

Get out your favorite circular objects, people, it’s Pi Day 2011!

As the math and science enthusiasts among us already know, March 14 (i.e. 3/14) is official Pi Day — a day to celebrate the number Pi, identified by the Greek letter p, which is used to calculate the circumference of a circle.

Pi is most often shortened to 3.14. But because the number is both irrational and transcendental, it “will continue indefinitely without repeating,” as the official Pi Day website, PiDay.org, kindly explains.

With the use of handy computers, Pi has now been calculated out to over 1 trillion digits past the decimal. It is Pi’s mysterious nature — the fact that it can never be entirely known — that has helped generate the adoration for it held by the mathematically inclined.

The famous symbol for Pi, p, was first used by Welsh mathematician William Jones in his work Synopsis Palmariorum Matheseos, which was published in 1706. It wasn’t until its adoption by Swiss mathematician Leonhard Euler in 1737, however, that the Pi symbol gained widespread popularity.

So, what is the purpose of Pi Day?

“It’s primarily a chance to have fun with the topic of math and science,” David Blater, author of The Joy of Pi, tells Time.com‘s NewsFeed blog. “And while it celebrates Pi officially, it’s more of an excuse to get excited and show the fun side of math and science.”

The first Pi Day was celebrated in 1989 at the San Francisco Exploratorium, which remains one of Pi Day’s primary promoters. Today, Pi Day celebrations take place in countless grade schools across the country.

While a wide variety of Pi Day celebrations are acceptable, some of the most popular include circle-measuring parties, watching the movie Pi, Pi recitation contests (to see who can accurately recall the most digits) and, of course, eating actual pie!