It all started when Dr. Michael Hartl suggested that the cake pi is a lie last year.

Hartl put “The Tau Manifesto” online last year, just in time for Tau Day, which is June 28th. Or 6 – 28. More on that later.

He bases the manifesto on the statements of another mathematician named Bob Palais, who is a research professor at the University of Utah.  He suggested that “π Is Wrong.”

Here’s the basic argument among mathematicians regarding pi and tau (π and τ).  And trust me, I do mean basic, because as soon as I see integral and sigma symbols on a page my eyes start twitching and I black out.

In short, pi is not a important or significant number, according to Hartl.  It is actually only half of the actual significant number, which is tau.  In the manifesto he argues that pi is not the true “circle constant” because it is the ratio of a circle’s circumference to its diameter.  The true circle constant is the ratio of a circle’s circumference to its radius, which is tau.

Since the radius is half the diameter, tau is double pi.  Pi = 3.14 and tau = 6.28.  June 28th.  Are we on the same page now?

People who follow this belief about tau have attempted to rid March 14th of its distinction as Pi Day and instead refer to it as “Half Tau Day.”  They believe that the world has an irrational love affair with pi, so we can’t shake what is actually a maddening way to calculate things.

I submit that “Pi Day” is so popular because it is equated to “Pie Day,” but that’s just a speculation.

Our society’s craziness, as explained in the manifesto –

What is really going on here is that, at its core, π is half of something. It’s the something that is fundamental, not π. And yet, when looking at the various equations of mathematics, even after reading this manifesto you might be tempted by the thought that the difference between π and τ isn’t really that important after all. You may find yourself saying, “Both numbers are important: sometimes π is better, sometimes τ is more natural, and sometimes they are equally good.”

This line of thinking misses the point. Imagine we lived in a world where we used the letter h to represent “one half”, and had no separate notation for 2h. We would then observe that h is ubiquitous in mathematics. In fact, 2h is the multiplicative identity, so how can one doubt the importance of h? All mathematicians and geeks agree, h is where it’s at.

But this is madness: 2h is the fundamental number, not h. Let us therefore introduce a separate symbol for 2h; call it “1”. We then see that h=1/2, and there is no longer any reason to use h at all. Arguing that π is important in mathematics is the same as arguing that h is important. Well, yes, lots of formulas contain a factor of 1/2, but that’s no reason to use a separate letter for the concept. The same goes for π: if the notation did not already exist, it seems unlikely that anyone would see fit to invent it. π, like our hypothetical h, is superfluous: h is just 1/2; π is just τ/2.

When you think of it that way, it does begin to sound a little backwards.

But the real question is whether or not Tau Day will catch on the way that Pi Day has.  Pi Day is huge on the interwebs.  It’s only in its infancy as a celebration, but how does Tau Day stack up?

Well, Tau has been trending on both Google and Twitter all day.  And the video below is gaining some viral steam.  The video, entitled “What Tau Sounds Like” is a musical representation of the first 126 decimal places of tau.  The artist, Michael John Blake, also musically interpreted pi, but that video was taken down due to a copyright claim.

Yes, someone thinks they own the rights to the digits of pi. Here’s what Blake has to say about that case on his YouTube channel –

Lars Erickson, composer of the “Pi Symphony” is suing me because he believes he owns the melody you get when you convert the digits of Pi to music. What he thinks he’s going to gain from suing a broke musician is beyond me, but his misguided notions of justice will be put in their place sooner or later. My legal team is presently working on my defense of this ludicrous claim, but the fact that this little song I made is now a federal case is just so stupid.

The song is quite beautiful, and pretty melancholy. Check it out –

Will Tau Day truly catch on? It’s too early to tell. But I’m sure its chances would rise if someone created a delicious dessert called Tau.