# How to celebrate Tau Day

### There's a movement afoot in mathematics to replace pi (3.14...) with tau (6.28...)

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Most everyone knows about Pi Day, March 14, or 3.14, and the various ways to celebrate it. But there is a growing movement amongst rebel math enthusiasts -- some who even call themselves math naturalists -- to displace pi in favor of tau . Whereas pi is the mathematical constant for the ratio of the circumference of a circle to its diameter, tau represents the ratio of the circumference to its radius. Since circles are defined as a set of points all an equal distance from the center, some argue that tau is a more natural way to measure a circle constant than pi. Here are six ways to celebrate Tau Day.

RELATED: 10 ways to celebrate Pi Day

What's the big deal over Tau Day anyway? Michael Hartl explains in great mathematical detail his arguments for the superiority of tau over pi. Inspired by an article, "Pi is Wrong" by University of Utah Mathematician Bob Palais, Hartl argues that pi is an "unnatural and confusing choice for the circle constant." Instead, the ratio of circumference to radius -- signified by the Greek letter tau -- is simpler because of the very definition of a circle being measured by its radius. Hence, tau = 2 x pi.

## Need more proof??

Watch "The Tau Manifesto" speech by Hartl where he, in great detail, explains the arguments for tau being a more natural constant number than pi. As a "truth-seeker" he cares about the correctness of explanation and as a teacher, he cares about clarity in math. He admits topping pi with tau could be a hefty task, though. "We are up against a powerful enemy," he says. "There is a centuries-old conspiracy to propagate pro-pi propaganda."

Now that you're (maybe) convinced about tau as a better alternative to pi, it's time to show your tau pride. And what better way than to celebrate on Tau Day, 6.28. What can you do? Any number of things, such as a wear a tau T-shirt in a variety of styles.

## Listen to beautiful tau music

Geeks, as they are, always look to express themselves in many ways, including through speeches, writings and even music, as has been done here, with a musical rendition of the tau digits.

## Make a run at the tau world record

Real tau enthusiasts memorizing and reciting the digits of tau. Be warned though, if you try to do this, you may have a hard time beating seventh-grader Ethan Brown.  A "math magician" whiz-kid, Ethan performs mathematical feats such as being able almost instantly calculate what any two or three digit number is squared, or he can tell you what day of the week any date in history was or will be. In May he took his talents into the record books, reciting 2,012 digits of tau, all to raise money for his local public library.

## Celebrate half Tau Day in March

If you're not ready to rebel against Pi Day quite yet, tau enthusiasts have another option for you: On March 14, 2013, simply celebrate half Tau Day. In the meantime, there are some who will continue to bring pi under attack, in true Hatfield-McCoy style.

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