With all the news about the coronavirus, the uncertainty, and stress many are currently facing, I wanted to write a post with some levity ¹. What better day than this! Today is both the first International Day of Mathematics (IDM) and Pi Day. These two celebrations cause great joy in math enthusiasts and give space to learn new (and old) exciting facts.

Proclaimed by UNESCO back in November, the goal of the IDM is to “explain and celebrate the essential role that mathematics and mathematics education play in breakthroughs in science and technology, improving the quality of life, empowering women and girls, and contributing to the achievement of the Sustainable Development Goals of the 2030 Agenda (SDG1-17) of the United Nations.”

This lofty goal is hoped to be achieved by worldwide events for all in schools, museums, libraries, and other spaces. This year’s International Day of Mathematics theme is “Mathematics is Everywhere” and there is a great website dedicated to exploring many examples of this theme available in seven different languages. Among my favorite examples on the page is “Search for Alien Life”, “Predicting Weather”, and “Epidemic Analysis”. Fun fact, in “Search of Alien Life”, they talk about the famous Arecibo Message sent from Earth to space back in 1974 from Puerto Rico. As explained in “Arecibo Message” by the SETI Institute,

“The message consists of 1679 bits, arranged into 73 lines of 23 characters per line (these are both prime numbers, and may help the aliens decode the message). The “ones” and “zeroes” were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes. A graphic showing the message is reproduced here. It consists, among other things, of the Arecibo telescope, our solar system, DNA, a stick figure of a human, and some of the biochemicals of earthly life. Although it’s unlikely that this short inquiry will ever prompt a reply, the experiment was useful in getting us to think a bit about the difficulties of communicating across space, time, and a presumably wide culture gap.” – SETI Institute

Through their Twitter account, IDM also shared this really neat collective video featuring submissions from all over the world in many languages showcasing all the places you can find math around you.

Don't miss our Mathematics is Everywhere collective video, created with submissions from all over the world:https://t.co/jrIvhv5DDz

Happy #idm314! #PiDay day #PiDay2020

— International Day of Mathematics (@idm314) March 14, 2020

The fact that this was the first celebration of the International Day of Math made me curious about the history of Pi Day. I was surprised to find that it started in 1988 and it was founded by physicist Larry Shaw. The first celebration was at the Exploratorium interactive science museum and consisted of a circular parade and eating fruit pies. You can still celebrate Pi Day at the Exploratorium by joining online and checking out some of their fun $\pi$ inspired activities.

The symbol for pi wasn’t used until the 1700s. As described in PiDay.org, before the symbol was used it was described as “the quantity which, when the diameter is multiplied by it, yields the circumference” and other long, roundabout descriptions. In the 1700s, the Swiss mathematician and physicist named Euler formalized the use of the Greek lowercase letter, π, as the notation for pi. This is the first letter of the Greek word, *perimetros*, which loosely translates to “circumference.”

In “Getting Ready for Pi Day, and also the Playful Math Blog Carnival”, Joseph Nebus shares a few some of his Pi day content in his archive including “Six or Arguably Four Things for Pi Day” on different ways to compute $\pi$ and a great list of comic strips from previous years. In the Crooked Pencil blog, Priya Narayanan writes about “Ramanujan: He who had the Pi & ate it too!”

“While Ramanujan’s formulae were progressively more and more accurate, what is more important to us today is his approach to the calculations, which provided the foundation for the fastest- known algorithm that, in 1987, allowed mathematician and programmer Bill Gosper to use the computer to churn out the value of π to around 17 million decimal places. Later, mathematicians David and Gregory Chudnovsky used his formulae as the basis of their own variants that allowed them to calculate the value of

πto an astounding 4 billion decimal places using their homemade parallel computer.”

The number $\pi$ has a really interesting history. In his book, Tales of Impossibility, David Richeson discusses how “compass and straightedge problems—squaring the circle, trisecting an angle, doubling the cube, and inscribing regular polygons in a circle—have served as ever-present muses for mathematicians for more than two millennia.” A review of the book in The Math Less Travel blog, describes the chapters as follows,

“Alternating with the “regular” chapters, Richeson includes a number of “tangents”, each one a short, fascinating glimpse into some topic which is related to the previous chapter but isn’t strictly necessary for driving the story forward (

e.g.toothpick constructions, Crockett Johnson, origami, the Indiana pi bill, computing digits of pi, the tau vs pi debate,etc.). Even though none of them are strictly necessary, taken as a whole these “tangent” chapters do a lot to round out the story and give a fuller sense of the many explorations inspired by the problems of antiquity.”

You also find many cool facts in this short article, “Here’s how pi matters every day not just March 14“, in particular, what is the current Guinness World Record for computing $\pi$.

“The Guinness World Record for a calculation of pi was set in 2019 by Emma Haruka Iwao using Google cloud software. She calculated pi to 31,415,926,535,897 digits.”

Pretty amazing! You can hear from Haruka herself on how she achieved this here. Another really interesting find was that IBM has released a new tutorial as part of its open-source online textbook to estimate $\pi$ on a quantum computer.

“The thing we’re trying to do here is to stay away from computing a million digits of Pi and more to use the theme of Pi Day to educate people on what quantum algorithms look like.” – Abraham “Abe” Asfaw, Global lead of quantum education at IBM.

But what makes Pi so interesting? As explained by Tom Crawford in “Make your Own Pi” it turns up in many important theories like Heisenberg’s Uncertainty Principle, Einstein Field Equations, and Newton’s Gravitational Constant to name a few.

“You may know it in terms of circles, but it has the rather fantastic knack of cropping up in the most unexpected places… Quantum Theory? Check. Einstein’s Theory of Relativity? Check. Newton’s Law of Gravity? Check. Three of the most important theories we use to explain the universe, and each of them has a formula containing the number Pi.”

Whether you celebrate International Mathematics Day and/or Pi Day, stay safe! Have ideas or feedback to share with us? You can reach us in the comments below or on Twitter (@MissVRiveraQ)!

¹ Note: Though I will recommend watching this great video from 3Blue1bBrown’s on exponential/logistic growth and epidemics and this recent article “Coronavirus, by the Numbers”.