Today is Pi Day. Math nerds around the world celebrate this mysterious number today. Your favorite Pie Shop may even run a special on pies today. Go ahead, celebrate!

The number π (sometimes spelled out as “pi”) is a mathematical constant approximately equal to 3.14, hence the celebration today, March 14. It is the ratio of a circle’s circumference to its diameter. It’s been used since the mid-18th century.

It is what mathematicians call an irrational number, meaning it can not be expressed exactly as a common fraction. So its decimal equivalent never ends and never settles into a permanent repeating pattern.

Mathematicians have been trying for thousands of years to accurately compute the value of π. With today’s high powered supercomputers, 20th and 21st century computer scientists have extended the decimal representation of π to over 10 trillion digits! Now, scientific applications generally require no more than 40 digits, so the primary motivation for these computations is the human desire to break records. But the calculation of π has been used to test supercomputers’ ability to compute high-precision multiplication algorithms.

In layman’s terms, they do it for fun, but have developed a use for it. I suppose not unlike the person at 3M who accidentally invented Post-Its, or the chef who was looking for a short cut for baking chocolate cookies and came up with chocolate chip cookies instead.

You will probably see a few minor headlines today about my fellow math nerds as they celebrate Pi Day with record-setting calculations. They’ll have to work pretty hard – the record for a MEMORIZED value of π is over 67,000 digits!! (One of the back pages of my high school math book had my own attempt at the value – the ENTIRE page, full of glorious numbers!)

Happy Pi Day!