Tau

2023-06-28

In mathematics, the Greek letter 𝜏 (Tau) represents the value of the double of a much more popular Greek letter, π. In simpler terms, 𝜏 = 2π.

The common approximation for 𝜏 is 6.28, which is why the 28th of June marks Tau Day.

But why make a separate symbol just to serve as twice the value of another symbol? It seems confusing. Well, many mathematicians believe that 𝜏 should replace π as the "circle constant." The reasoning given for this is intricately outlined in Michael Hartl's The Tau Manifesto.

The currently accepted "circle constant" (π) is defined as the ratio of a circle's circumference to its diameter. The manifesto argues that the key component in choosing the circle constant should be the radius rather than the diameter (width). There are infinitely many shapes with a constant width, but only one shape with a constant radius. The manifesto also goes into various ways that using Tau makes more intuitive sense in the context of Trigonometry. This is because 360 degrees (a full circle) would then be denoted simply as 𝜏 radians as opposed to 2π radians.

So mark your calendars. Next year's Tau Day will be here before you know it, and it's important to be able to lecture to your friends about the superiority of 𝜏.