Pi Day!

I don't know if you're aware of this, but today is International Pi Day, on which we celebrate the numeral 3.14159265 etcetera etcetera etcetera.

In celebration of this momentous occasion (March Fourteenth, or 3/14, you see) I intend to: 1. eat some pie, and 2. tell you random stuff about pi.

• Pi is the what you get if you divide a circle's circumference by its diameter. If you have a circle that's one foot across, the distance around it is (about) 3.14159 feet.

• The Babylonians knew this (sort of), and so did the Egyptians (though they were a little further off).

• Modern scientists have determined the value of pi to more than 1.2 trillion places (it goes on forever), but even if you only knew pi to 47 places, you could still build a circle so precisely that it would surround the entire visible universe and only be off by the width of a proton.

• 3.14.1879 is Albert Einstein's birthday.

• Pi puzzlingly also appears in the field of Probability: if you drop a one-inch needle on a piece of paper with two parallel lines one inch apart, watch how often part of the needle lands on a line. Take the number of drops, multiply it by two, and divide it by the number of hits and you'll get something close to 3.14159.

• I don't even *kind of* understand that. The proof involves words like "ordinate" and "abscissa."

• "Abscissa" would be a good name for a poodle.

Now let's go eat some pie!