# On National Tau Day, Pi Under Attack

Google celebrated March 15th (or "Pi Day" as many call it) with this doodle. But sadly, the company has not honored Tau Day in the same way.  (Google)

Pi, the circle constant in mathematics, is under attack, The Advertiser reported Tuesday, with an underground movement rounding up support for its successor, Tau.

Pi is the "irrational" infinite number you get when you divide the circumference of a circle by its diameter. It starts 3.14159265, it fits into all kinds of equations and it turns up in strange places such as the fractal geometry of the Mandelbrot Set.

Tau is the number you get when you use a circle's radius instead. It fits neatly into equations in place of 2Pi and clears up the problem of radians, which is the way mathematicians measure angles.

U.S. physicist, educator, and entrepreneur Dr Michael Hartl, author of The Tau Manifesto, says Pi is a "confusing and unnatural choice" for the circle constant. "I find it fascinating that the absurdity of Pi was lying in plain sight for centuries before anyone seemed to notice," he said.

And as the approximate value of Tau is 6.28, twice Pi's 3.14, the dissident mathematicians have declared June 28 to be Tau Day -- as June 28 is written as 6.28 in American style, The (London) Times reported.

"For all these years, we have been looking at the wrong number when we have been looking at Pi," said Kevin Houston, of the School of Mathematics at the University of Leeds, who is leading the British arm of the Tau campaign.

"Pi simply isn't the most natural number that we should associate with a circle. The proper number is 2Pi, or Tau."

Meanwhile in Australia, news.com.au reported that maths genius Michael Blake has composed a melody based on the value of Tau.

Each of the eight notes in a major scale -- and their corresponding major, minor and diminished chords -- are assigned a numerical value; C being one, D two and so forth. Blake composed "What Tau Sounds Like" based on the numerical value of Tau to 127 decimal places.

The Australian Science Exchange was so wooed by the melody that the Elder Conservatorium of Music was to perform Blake's musical notation at a Tau Day celebration at the Royal Institution of Australia in Adelaide on Tuesday.

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