What is Pi Day? Who started it, and when?

Google Doodle celebrates Pi Day with a pie recipe by celebrated pastry chef Dominique Ansel; NASA has shared its annual Pi in the Sky challenge

What is Pi Day? Who started it, and when?

Pi Day doodle has a pie baked and built by award-winning pastry chef Dominique Ansel

Observed on March 14 (3/14) every year, Pi Day is an annual celebration of the mathematical constant π (pi), which calculates to over 1 trillion digits beyond its decimal point. While its digits go on infinitely, Pi is most popularly known by the first three: 3.14, which is why March 14 has come to be known as the Pi Day.

Said to have been first recognised in 1988 by physicist Larry Shaw, Pi Day is now celebrated across the word in different ways.

While many celebrate the day with a slice of their favourite pie, thanks to the number’s similar sounding name, there are others who dedicate the day to the genius of mathematics.


Wednesday’s Google Doodle has a beautifully baked pie cooked and built by award-winning pastry chef and creator of the Cronut® Dominique Ansel. It pays homage to the mathematical constant by representing the pi formula (circumference divided by diameter) using a pie.

Google has also shared Chef Dominique’s unique recipe with the viewers.

Pi helps determine the circumference or the surface area of a round celestial body. It represents the ratio between a circle’s circumference to its diameter, and is a fundamental element of many mathematical fields.

NASA celebrates Pi Day by sharing a series of cosmic calculations to be solved by the public. Its ‘Pi in the Sky’ challenge, created by Jet Propulsion Laboratory’s Education Office, features math problems that illustrate how pi can be used to learn about all kinds of curious features of the universe, including earthquakes on Mars, helium rain on Jupiter, and planets orbiting other stars.


This year’s NASA Pi Day Challenge features the agency’s InSight Mars lander, Kepler space telescope and Juno spacecraft at Jupiter – plus a visit from an interstellar object. (Photo: NASA website)


In its fifth year, the annual “Pi in the Sky” illustrated math challenge features pi-related space problems that people can do at home.

“All of the problems in the ‘Pi in the Sky’ challenge are real problems that JPL scientists and engineers solve using pi,” the NASA website quotes Ota Lutz, a senior education specialist at JPL who helped create the Pi Day Challenge.

This year’s NASA Pi Day challenge features the agency’s InSight Mars lander, Kepler space telescope and Juno spacecraft at Jupiter — plus a visit from an interstellar object. The solutions to the problems posted online on March 9 will be published on March 15.

In previous years, Pi in the Sky featured problems about how NASA space probes gather information about objects in our solar system, how scientists search for planets around other stars, and how astronomers predict the occurrence of solar eclipses.

“The Pi in the Sky problems give people a little glimpse into what goes on at JPL,” Lutz said. “And that’s empowering, because it shows people that they can understand some of the magic that goes into space exploration.”