If there was ever a year to commemorate Pi Day in a big way, this is it. The date of this Saturday—3/14/15—gives us not just the first three digits (as in most years) but the first five digits of pi, the famous irrational number 3.14159265359… that expresses the ratio of a circle’s circumference to its diameter.
For an extra thrill, be sure to observe Pi Day on 3/14/15 at 9:26:53 (A.M. and/or P.M.!), which will give you a full 10 digits of pi—an occurrence that will not roll around for another century. (Of course, the specialness of this year really only works in the U.S. and other places that commonly put the month before the day, rather than in Europe, say, where they would note the date as 14/3/15.) And if this Saturday is not already special enough, it is also Albert Einstein’s birthday, giving math and science enthusiasts even more reason to revel.
Pi fans can celebrate this weekend with a wealth of math- (and baked goods–) related opportunities. Traditionalists will of course bake pies, both because of the pun and because of their circular nature (not to mention their tastiness). For the sugar-averse, pizzas have the right shape, and the right first two letters as well.
Science museums around the country are also planning live events. The National Museum of Mathematics in New York City, for example, will gather people in Madison Square Park to light up a circle around the central fountain and compare its circumference with the distance across it—accompanied by free hot chocolate and pie. Other festivities are being held at Exploratorium in San Francisco, the Air Force Research Laboratory in Dayton, Ohio, Princeton University (which is having a pie-eating contest, among other activities) and the National Cryptologic Museum near Washington, D.C., among many more.
If you bake a pie, eat a pizza or party with other pi fans, please send us a picture and description of how you observed the Pi Day of the Century for a gallery we plan to post next week.