Tau Day an anti-Pi Day holiday is an unofficial observance held every year since 2010 on 28 June. The day began to recognize tau, τ, a ratio constant describing the relationship between the circumference and the radius of a circle. In recent years, some mathematicians and physicists have argued for the replacement of pi (π) by tau.
An unofficial holiday that operates on a quite simple premise: that PI is wrong. This holiday celebrates Tau—a replacement for PI that sets the circle constant at approximately 6.28. It is anti-Pi because Pi equals a circle’s circumference divided by its diameter (3.14), while Tau represents a circle’s circumference divided by its radius. Tau is considered by some to be a lot more accurate way to find a circle’s circumference, but not every in the mathematics community agrees. As a result, this holiday is still somewhat on the fringes of mathematical holidays. Regardless of whether this holiday is used as a bookend with PI Day or whether it is celebrated as a holiday.
History of Tau Day
On 28 June 2010, “The Tau Manifesto” launched at the same time as the first Tau Day. “The Tau Manifesto” was a book written by Michael Hartl that was dedicated to the lesser-known number. In it, pi is referred to as unnatural and confusing. Pi compares a circle’s circumference with its diameter, and many mathematicians are disinterested in this quantity whereas tau is the number that connects a circumference to that quantity. The day is used to celebrate all of mathematics, but tau specifically still has an uphill battle in receiving recognition.
The concept of replacing pi with tau as a better way to describe the relationship between a circle’s circumference and its radius was first brought up by mathematics professor, Bob Palais in the Mathematical Intelligencer in an article called π is wrong! This was followed by the publishing of the Tau Manifesto by physicist Michael Hartl. Both articles called for the replacement of pi by tau. Tau, the ratio of a circle’s circumference to its radius, is equal to 2 π or 6.283.
Tau is not yet widely accepted within the scientific community, though there is a large community of scientists and technologists who have called for the replacement of pi by tau.