# NASA Celebrating Pi Day

March 14 is Pi Day, a celebration of the number known as pi.

NASA is celebrating on the way that only NASA can, with the fifth annual “Pi in the Sky” illustrated math challenge, featuring pi-related space problems that people can do at home.

Pi is often abbreviated as 3.14, which is why Pi Day is celebrated on March 14, or 3/14; but there are actually an infinite number of digits in pi.

Pi belongs to a special class of numbers known as "irrational numbers."

These numbers contain an infinite number of digits that do not repeat or show any pattern, and they cannot be represented as a ratio of two integers.

Using computer programs, mathematicians have calculated trillions of those digits so far.

But pi is also an intensely practical number, and something of a work-horse when it comes to solving problems in the sciences.

Pi, for example, can be used to derive characteristics of a circle or a sphere, such as circumference or surface area.

Scientists and engineers at NASA’s Jet Propulsion Laboratory say they frequently use pi to learn about moons, planets, stars and other spherical bodies, and to track the orbits of satellites and spacecraft.

The “Pi in the Sky” challenge, which has been created by JPL’s Education Office, features math problems that illustrate how pi can be used to learn about all kinds of curious features of the universe.

These include earthquakes on Mars, helium rain on Jupiter, and planets orbiting other stars.I

n fact, all of the problems in the ‘Pi in the Sky’ challenge are real problems that JPL scientists and engineers solve using pi.

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 new problems have already been posted online, according to a NASA release.

The space agency promises that solutions will be posted on March 15.

If you're game for the challenge, you can find it here: https://www.jpl.nasa.gov/edu/nasapidaychallenge