State of the Tau 2017

Happy Tau Day, everyone!

We’ve come a long way since the launch of The Tau Manifesto in 2010, and this year saw continued progress and interest in τ, the true circle constant.

In case you’re short on time, here are three quick action items:

  1. Join me and fellow tau enthusiasts at the official Tau Day 2017 party at Urth Caffé in Santa Monica, California.
  2. Support Ryan Brancheau’s Tau Euro Magnet Kickstarter. (I’m a backer, but I don’t have any financial interest in the project.)
  3. Get your Official Tau Shirt now for a limited time.

There are many ways to celebrate Tau Day, of course, and I hope you’re having fun.

I’m celebrating this year by giving an updated version of the original Tau Talk at Google’s Los Angeles office in beautiful Venice, California. Joining me there will be original “π Is Wrong!” author Bob Palais as a special guest!

The Google event is closed to the public, but (as noted in the action items above) anyone in the Los Angeles area is welcome to join me and fellow tau enthusiasts for the official Tau Day 2017 party.

The plan, as usual, is to eat twice as much pie!

Tau in Scientific American

Just in time for Tau Day 2017, Scientific American has published “The Tao of Tau”, an exploration of the use of the letter tau in science, engineering, and mathematics. The article opens with an acknowledgment of the true circle constant:

“It is lamentable that there’s no famous dessert named ‘tau,’” Michael Hartl told me recently at a sunny, stylish café in Venice, California. He reluctantly admitted that pi, the constant approximately equal to 3.14, has this one advantage over tau, a number he introduced to replace it.

Read the whole thing there. Congratulations to author Elizabeth Landau on a job well-done!

Tau in Python

One of the most exciting tau events this year involves the Python programming language, one of the most popular and powerful languages in use today.

Although nowadays I’m better known for my contributions to the Ruby community, Python was actually the first programming language I really loved.

It is therefore with great pleasure and pride that I announce the inclusion of tau in the latest version of Python. That’s right—after some lively debate, the BDFL of Python, Guido van Rossum, decided to include tau as part of the official math library in Python 3.6:

>>> from math import tau >>> tau 6.283185307179586

Go forth and wield tau, O brave Pythonistas!

Tau N Pi

Another welcome tau contribution came via the son of reader Bobby Cieszki, who created a haunting parody of Kid Cudi’s song “Day ‘N’ Nite” called “Tau N Pi”. Give it a listen—it’s really quite extraordinary.

Key Lime Tau

Last year I mentioned that two breweries (Hawkshead Brewery in the UK and Crooked Stave here in the US) had collaborated to bring the world Key Lime Tau beer. Sounds great, right?

Alas, I soon discovered that it is rather hard to come by.

Well, tauist Richard Soderberg took this as a challenge. He diligently tracked down a vendor, and procured for me a generous supply.

Michael Hartl with Key Lime Tau beer

Verdict: Deliciously sour, and worthy of its name!

Thanks, Richard!

Tau art

Tom Magliery reports on an art project he created involving a collage of numbers—found in the wild, so to speak—assembled to form the digits of tau:

Tau digits collage


Los Alamos National Labs

On Pi Day (or, as I prefer to call it, Half Tau Day), Los Alamos National Labs acknowledged tau in its Bradbury Science Museum newsletter article called “Celebrate Pi Day on March 14 (3.14)”:

Pi and controversy (Didn’t see that coming, did you?)

Back in 2001, Bob Palais, a math professor at the University of Utah, wrote an opinion piece for The Mathematic[al] Intelligencer called “π is Wrong!” Apparently, the counterargument against pi is that it is often used as 2π for equations, so why not just use 6.28 instead of 3.14?

That call reemerged again in 2010, when Michael Hartl wrote a book [sic] called The Tau Manifesto making a similar argument and offering up the name of “tau” as the shorthand of 2π or just τ as its symbol.

He’s called for an annual Tau Day on June 28 (6/28 on the American calendar) to raise awareness of the tau concept.

In case you don’t have enough interest to absorb the contents of his book [sic], Michael’s website includes two videos explaining the concept of tau in both short (14 minutes) and long (51 minutes) versions to bring you up to speed.

Dutch newspaper article

Alert reader Wouter Vink passed along this remarkable sighting of tau in an article from a Dutch newspaper:

Tau in a Dutch newspaper

I can’t read Dutch, but this has to count as a good sign. Tau continues to be an international phenomenon!

Tau Euro Magnets

Tauist Ryan Brancheau has launched a tau Kickstarter to make European-style oval magnets with 6.28 in the middle and further digits around the side. Let’s see if we can get Ryan’s project to tip!

Tau Euro Magnet

Tau Shirts

Finally, as usual I’ve relaunched Tau Shirt sales as part of the Tau Day celebrations.

To paraphrase Yogurt from the movie Spaceballs:

Merchandising! Merchandising! Where the real money from the Manifesto is made!

Supporting tau is a labor of love, of course, and it isn’t exactly a major profit center. But you keep asking for tau shirts, so I keep selling them!

Tau Shirt

Tau Day 2017

Thanks to all the tauists out there who continue to make this quirky project so much fun. Hope to see you at the party.

Happy Tau Day!

Michael Hartl
Founder, Tau Day
Author, The Tau Manifesto

State of the Tau 2016

Happy Tau Day, everyone! It’s hard to believe it’s already been six years since The Tau Manifesto launched and the real battle against pi’s supremacy began.

I don’t keep careful statistics, but I can confidently state that awareness of tau is enormously widespread. As an active member of the Caltech alumni community, for example, I frequently meet Caltech undergraduates, and they’ve virtually always heard of Tau Day.

Similarly, I’ve found in the programmer community that a fair fraction have heard of tau. In my own little corner of tech, every so often someone will freak out upon realizing that the author of the Ruby on Rails Tutorial and The Tau Manifesto are the same person. Indeed, today I hope to blow more than a few such minds, because I’ve just launched the new edition of the Ruby on Rails Tutorial book—on Tau Day!

One cool thing is seeing people wearing the Official Tau Shirt, which as usual is available for a limited time (sales expire tomorrow). For example, my mother reported seeing one on an elementary school student in Orange County, California, last year. And just a couple of weeks ago I was driving through downtown Los Angeles when I saw a woman wearing a Tau Shirt. I recognized her as my friend Carol Hoffstedt, so I rolled down the window and said, “Hey, Carol! You win!” I mean, what are the odds!?

As in previous years, people continue to amaze me with the incredible variety of creative projects inspired by tau. For example, an alert tauist passed along this remarkable Tau Day Sonnet, written for Tau Day last year:

As a big fan of the sonnet form myself, I can hardly imagine a better Tau Day present than this. Well, maybe beer (see below).

A second tauist, this one at MIT, told me about a “Tau Day Hack” involving “Tau on the Cow” (don’t ask me exactly what it means!):

MIT Tau on the Cow

I’m glad to see MIT picking up the tau ball and running with it—and challenge my fellow Techers at Caltech to do the same. (Hint, hint!)

Finally, the ever-enthusiastic Joseph Lindenberg passed along this fantastic bit of tau culture found in a most unexpected place: a specialty beer from Hawkshead Brewery called Key Lime Tau!

Key Lime Tau beer

As described on its website:

The [Key Lime Tau] beer, originally a collaboration brew with Crooked Stave (USA), is our take on a key lime pie. It was brewed on both sides of the Atlantic, hence two ‘pies’ and is 6.28% in strength.

6.28% in strength! How can you not love that?!

Alas, it looks like Key Lime Tau beer is pretty hard to come by, and I haven’t yet procured any for myself, but for next year I’ll do my best to fulfill the promise implicit in this lovely poster, and drink Hawkshead Key Lime Tau on International Tau Day!

Hawkshead Key Lime Tau poster

Until next year—Happy Tau Day!

Michael Hartl
Founder, Tau Day
Author, The Tau Manifesto

State of the Tau 2015

Happy Tau Day 2015! Interest in the true circle constant (τ = C/r = 6.283185…) and The Tau Manifesto continued unabated this year, highlighted by a surge of attention on the “Pi [Half Tau] Day of the Century” (3/14/15). (Tau will have its revenge on 6/28/31—party at my place!) As one of the leaders of the “opposition”, I was invited to the Pi Day festivities at the Exploratorium in San Francisco—the organization that originally created Pi Day—but I was on vacation in Barcelona at the time and was unable to attend. (I know, rough life!) That the invitation was proffered in the first place is an excellent sign, though, as it serves as proof that even the Paladins of Pi recognize tau as a legitimate rival.

Here are some of the highlights since last year’s Tau Day:

Using tau instead of pi makes math clearer, and thus easier to understand.

Using pi is like having a weird car whose odometer and speedometer display half-miles and half-miles-per-hour, while all the road signs show miles and miles-per-hour.

(The road signs of math are naturally in units of tau.)

So you constantly have to convert between what your car says and what the road signs say. 55 mile-per-hour speed limit? Make sure your speedometer needle doesn’t go over 110. But instead of nice round numbers like 55, imagine the sign says 68.7 miles-per-hour. So your speedometer needle shouldn’t go above… how much? Your trip odometer reads 35.7. So you’ve traveled… how many miles?

Sometimes you must multiply by 2. Sometimes you must divide by 2. And before doing either, you must always stop and decide which to do in this particular case. If you’re driving in heavy traffic, or bad weather, or you’re lost, you don’t want that distraction. The same is true if you’re lost while trying to learn trigonometry.

Thanks for all the support! For me, that makes for a very happy Tau Day.

Michael Hartl
Founder, Tau Day
Author, The Tau Manifesto

State of the Tau 2014

Happy Tau Day, everyone! This was a huge year for $\tau$, with continued adoption in programming languages and classrooms, appearances in a couple of prominent webcomics (xkcd & SMBC), and a big endorsement from Google. I also received an amazing parable about pi and tau from a precocious high-school student—seriously, give it a read.

Here’s a list of some of the highlights since Tau Day 2013:

I’ve been gratified by the continued enthusiasm for $\tau$ since the launch of The Tau Manifesto in 2010. I especially appreciate the support of Robert Palais, Joseph Lindenberg, Peter Harremoës, Robin Whitty, Vi Hart, and all the tauists who’ve reached out about $\tau$ in the past four years. Here’s to another great year ahead for $\tau$!

Michael Hartl, Tau Day 2014

State of the Tau 2013

It’s been a big year for $\tau$. When I launched The Tau Manifesto back on Tau Day 2010, I hoped that $\tau$ might strike a chord, but its popularity has exceeded my wildest expectations—due in large part to the efforts of the many ardent tauists who picked up $\tau$ and ran with it. Now three years on, activity surrounding both the constant and the notation continues apace. In honor of Tau Day 2013, I’ve listed below some of the highlights from the last year. Enjoy, and Happy Tau Day!

Michael Hartl
Founder, Tau Day
Author, The Tau Manifesto

Note: I’d like to thank Joseph Lindenberg, Robert Palais, Robin Whitty, and Peter Harremoës for their help in compiling this list.

Radians with tau