Happy Tau Day!
Argh, I was supposed to post this yesterday, of course. If you don’t know what tau (τ) is, I could just tell you that it’s C/r, which is approximately 6.28, hence 6/28 is Tau Day. But that doesn’t tell you its exact value, or why we should care, or even what it’s used for. Everyone know π, or pi, which of course is C/d, or approximately 3.14; but why is tau better? In what sense is tau greater than pi?
For an answer, check out Vi Hart’s delightful and informative videos on the subject: