Pi Day is celebrated every March 14, but this year is being called the "Pi Day of the Century."
The occasion marks the time when the date, when written in the style used by most Americans, 3/14, matches the first three digits of pi. This year, the date will be 3/14/15, even closer to the value of pi, which begins 3.1415.
That number, an irrational number having no last digit, is the ratio of a circle's circumference to its diameter. Mathematicians know that pi is irrational because simple formulas can be determined if the last digit is even or odd. When this process is carried out on a formula that produces pi, the result is that the last digit of the number is both even and odd. Since no such number exists, there can be no last digit. Computers have been able to calculate the figure to trillions of decimal points.
Many math enthusiasts celebrate the annual event by eating pie. March 14 is also the birthday of Albert Einstein, who would have been 136 years old this year.
Jet Propulsion Laboratory is hosting a trivia event to celebrate the occasion, asking questions centered on the history of spacecraft. Astronomers, astrophysicists and other scientists use pi in a wide range of equations and other applications. Most formulas involving rotation of bodies or orbits use pi, making the number a staple in astronomical calculations.
"On Pi Day, I will think about the nature of a day, as Earth's rotation on its axis carries me on a circle 21,000 miles (34,000 kilometers) in circumference, which I calculated using pi and my latitude," Marc Rayman, chief engineer and mission director for the Dawn spacecraft currently orbiting the dwarf planet Ceres, said.
The distance between stars is calculated using a branch of mathematics known as spherical trigonometry, a variation of the math normally used, on a flat plane.
The irrational number even comes up in calculations designed to determine the amount of hydrogen that could be present in the oceans of Europa, one of the moons of Jupiter.
At 9:26:53 in the morning and at night on March 14, the date and time could be expressed as 3/14/15 9:26:53, similar to the first 10 digits of the number, 3.141592653. This will be the closest approximation of pi, which will take place for the next 100 years.
Officials at NASA have also produced a Web page of classroom activities related to Pi Day for educators and students.
Many science and math enthusiasts will be celebrating the occasion with pie and pizza. It is a holiday Albert Einstein would love!
Photo: Stuart Caie | Flickr
