What is Pi Day all about? Math, science, pies and more

Math enthusiasts around the world, from college students to rocket scientists, celebrate Pi Day on Thursday, which is March 14 or 14: the first three digits of an infinite number with many practical uses.

Around the world, many people celebrate the day with a piece of cake: sweet, savory, or even pizza.

Simply put, pi is a mathematical constant that expresses the relationship between the circumference of a circle and its diameter. It is part of many formulas used in physics, astronomy, engineering and other fields, dating back thousands of years to ancient Egypt, Babylon and China.

Pi Day dates back to 1988, when physicist Larry Shaw began celebrations at the Exploratorium science museum in San Francisco. However, the holiday did not truly gain national recognition until two decades later. In 2009, Congress designated every March 14 It will be the big day and will hopefully stimulate more interest in math and science. Fittingly, that day is also Albert Einstein’s birthday.

Here’s a little more about the origin of the holiday and how it is celebrated today.

WHAT IS PI?

Pi can calculate the circumference of a circle by measuring the diameter (the straight distance through the center of the circle) and multiplying it by the number 3.14 or more.

It is considered a constant number and is also infinite, that is, mathematically irrational. Long before computers, historical scientists like Isaac Newton spent many hours calculating decimals by hand. Today, using sophisticated computers, researchers have obtained trillions of digits for pi, but there is no end.

WHY IS IT CALLED PI?

It did not receive its name until 1706, when Welsh mathematician William Jones began using the Greek symbol for the number.

Why that letter? It is the first Greek letter of the words “periphery” and “perimeter,” and pi is the ratio between the periphery (or circumference) of a circle and its diameter.

WHAT ARE SOME PRACTICAL USES?

The number is key to accurately pointing an antenna at a satellite. It helps determine everything from the size of a huge cylinder needed in refinery equipment to the size of paper rolls used in printers.

Pi is also useful in determining the necessary scale of a tank serving heating and air conditioning systems in buildings of various sizes.

NASA uses pi every day. It is key to calculating orbits, positions of planets and other celestial bodies, rocket propulsion elements, spacecraft communication and even the correct deployment of parachutes when a vehicle lands on Earth or Mars.

Using just nine digits of pi, scientists say they can calculate the circumference of the Earth so accurately that they are only off by about a quarter of an inch (0.6 centimeters) for every 25,000 miles (about 40,000 kilometers).

BUT IT’S NOT JUST MATHEMATICS

Each year, the San Francisco museum that coined the holiday hosts events, including a parade around a circular plaque, called Pi Shrine3.14 times, and then, of course, parties with lots of cake.

Across the country, many events are now held on college campuses. For example, Nova Southeastern University in Florida will host a series of activities, including a game called “Mental Math Bingo” and an event with free pizza (pies) and, for dessert, the required pie.

“Each year, Pi Day gives us a way to celebrate mathematics, have fun, and recognize how important mathematics is in our lives,” said Jason Gershman, chair of NSU’s mathematics department.

At Michele’s Pies in Norwalk, Connecticut, manager Stephen Jarrett said it’s one of the biggest days of the year.

“We have hundreds of cakes going out for orders (Thursday) to businesses, schools and just individuals,” Jarrett said in an interview. “Pi Day is a very fun and silly holiday because it is a mathematical number that people love to turn into something fun and delicious. “So people celebrate Pi Day with sweet and savory pies, and it’s just an excuse to treat yourself.”

NASA has its annual “Pi Day Challenge” online, offering people many games and puzzles, some of them straight from the space agency’s handbook, such as calculating the orbit of an asteroid or the distance a lunar rover would need to travel each day to study a certain lunar area.

AND EINSTEIN?

Possibly the best-known scientist in the world, Einstein was born on March 14, 1879 in Germany. The infinite number of pi was used in many of his groundbreaking theories and now Pi Day gives the world another reason to celebrate his achievements.

In a bit of mathematical symmetry, famous physicist Stephen Hawking died on March 14, 2018, at age 76. Still, pi is not a perfect number. He once said this:

“One of the basic rules of the universe is that nothing is perfect. Perfection simply does not exist. Without imperfection, neither you nor I would exist.”

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Associated Press video journalist John Minchillo contributed from Norwalk, Connecticut.