By Curt Anderson, Associated Press
From college kids to rocket scientists, math enthusiasts worldwide celebrate Pi Day on March 14 (3/14) – the first three digits of the infinite number pi, which has many practical uses.
Many people worldwide will celebrate the day with a slice of pie – sweet, savory, or even pizza.
In simple terms, pi is a constant in mathematics that represents the ratio of a circle's circumference to its diameter. It is part of various formulas used in physics, astronomy, engineering, and other fields, with roots dating back thousands of years to ancient Egypt, Babylon, and China.
Pi Day originated in 1988 when physicist Larry Shaw initiated celebrations at the Exploratorium science museum in San Francisco. It didn't gain national recognition until 2009 when Congress designated every March 14 as the official day in the hopes of generating more interest in math and science. Notably, the day also happens to be Albert Einstein’s birthday.
Here’s some more about how the holiday began and its current celebration.
WHAT IS PI?
Pi can be used to calculate a circle's circumference by multiplying the diameter – the distance across the circle's middle – by the number 3.14 and beyond.
Pi is a constant and an infinite number, which means it is mathematically irrational. Before computers, historic scientists like Isaac Newton spent countless hours manually calculating its decimal places. Today, using advanced computers, researchers have determined trillions of digits for pi, yet there is no end.
WHY IS IT CALLED PI?
It received its name in 1706, when Welsh mathematician William Jones started using the Greek symbol for the number.
Why that letter? It's the first letter in the Greek words “periphery” and “perimeter,” and pi represents the ratio of a circle’s periphery – or circumference – to its diameter.
WHAT ARE SOME PRACTICAL USES?
The number is crucial for accurately aligning an antenna toward a satellite. It is used to determine various things ranging from the size of a large cylinder required in refinery equipment to the dimensions of paper rolls used in printers.
Pi is also useful in determining the required size of a tank used for heating and air conditioning systems in buildings of various sizes.
NASA uses pi daily. It is crucial for calculating orbits, the positions of planets and other celestial bodies, elements of rocket propulsion, spacecraft communication, and even the correct deployment of parachutes when a vehicle splashes down on Earth or lands on Mars.
By using just nine digits of pi, scientists claim they can accurately calculate the Earth’s circumference, with an error of about a quarter of an inch (0.6 centimeters) for every 25,000 miles (about 40,000 kilometers).
However, it's not just about math.
Every year, the San Francisco museum that created the holiday hosts events, including a parade around a circular plaque, called the Pi Shrine, 3.14 times – and then, of course, celebrations with plenty of pie.
Across the country, numerous events now occur on college campuses. For instance, Nova Southeastern University in Florida will host a variety of activities, including a game called “Mental Math Bingo” and an event featuring free pizza (pies) – and for dessert, the essential pie.
“Every year, Pi Day gives us an opportunity to celebrate math, have some fun, and recognize how important math is in all our lives,” stated Jason Gershman, chair of NSU’s math department.
At Michele’s Pies in Norwalk, Connecticut, manager Stephen Jarrett stated it is one of their busiest days of the year.
“We have hundreds of pies being delivered for orders (Thursday) to companies, schools, and individuals,” Jarrett said in an interview. “Pi Day is such a fun, lighthearted holiday because it’s a mathematical number that people love to turn into something enjoyable and delicious. So, people celebrate Pi Day with sweet pies, savory pies, and it’s just an excuse for a little treat.”
NASA holds its annual “Pi Day Challenge” online, providing people with numerous games and puzzles, some of which are directly from the space agency’s own playbook, such as calculating the orbit of an asteroid or the distance a moon rover would need to travel each day to survey a specific lunar area.
WHAT ABOUT EINSTEIN?
Possibly the most famous scientist in the world, Einstein was born on March 14, 1879, in Germany. The infinite number of pi was used in many of his important theories and now Pi Day gives the world another reason to celebrate his accomplishments.
In a bit of math symmetry, well-known physicist Stephen Hawking passed away on March 14, 2018, at age 76. Still, pi is not a perfect number. He once expressed this thought:
“One of the fundamental rules of the universe is that nothing is perfect. Perfection simply doesn’t exist. Without imperfection, neither you nor I would exist.”
Associated Press video journalist John Minchillo contributed from Norwalk, Connecticut.
