by Todd Wright 3/14/15 – International Pi Day is celebrated each year on March 14 (3.14) at 1:59pm (3.14159) by some math and science professionals, a well as by many math classrooms in our children’s schools. What is unique about this year is the additional two digits which the year 2015 give Pi enthusiasts to work with (3.1415). This is a once in a lifetime event, and Pi enthusiasts are taking full advantage of it. This year, some will celebrate this year at the traditional time of 1:59pm, while others will celebrate their peak of festivities on 3/14/15 at 9:26:53am (3.141592653). For those who are a little rusty at math, Pi is the ratio of the circumference of a circle to its diameter. Most people who are not mathematicians will simply say that Pi is approximately 3.14 for short, or perhaps 3.1415 “and then some.” However, this ratio is special in that it has never been completely calculated to completeness by humans or computers – the numbers after the decimal go on and on. Thanks to modern computer technology, Pi is calculated to thousands of digits with relative ease, and to trillions of digits by dedicated experts, but this is still not the complete number. Pi is called an irrational number. The complete numerical representation of Pi is incomprehensible, and yet, this ratio exists for every circle that we see. Pi is a key component of the mathematical subsystem underlying the universe. Whether you knew it or not, Pi is part of your life. If you want to celebrate Pi with math and science enthusiasts, visit the Adler Planetarium and WBEZ 91.5 for their celebration of The Ultimate Pi Day 2015. Or perhaps, celebrate Pi day in the traditional way, as many do, with a slice of your favorite pie – and then some.