# Why Are People So Obsessed With Pi? A Non-Nerd Explainer

Today, as you’ve probably noticed, is Pi Day. Nerds are running around with pies, jokes about geometry you last thought about in high school are everywhere, and more than a few people are profoundly confused, if overjoyed that the one shy coworker brought in pie today. So, why the love of a Greek letter?

So, what the heck is pi, exactly?

Pi, or π, is the ratio of a circle’s circumference to its diameter. It’s a constant ratio, regardless of the size of the circle, which is why 2πr is how you figure out a circle’s circumference.

It is, as far as mathematicians are able to tell, completely random. Pi is either a number so precise that its exact proportions stretch off to infinity, or a demonstration that the universe is fundamentally unfathomable, depending on who you ask and their outlook on life. Essentially, we know what pi is, but we don’t know why pi is.

Come on, it can’t be totally random.

Pi has been calculated up to ten trillion digits, with no sign of stopping. Furthermore, any kind of test for statistical randomness has been passed with flying colors by pi. Pi is, by current standards, completely random.

So why the nerd obsession, if they can’t figure it out?

Well, therein lies the obsession: Nobody can figure it out. The thing about pi is that we know it works; humanity uses it every day for essentially anything that has a circle in it, from your coffee cup to the columns holding up your parking garage to the wheels on your desk chair. It’s been thoroughly tested on a practical level in construction, design, physics, you name it.

And yet, pi is also unknown. Why does it work? Why does a finite shape of measurable length need a number that extends possibly beyond the ability of human beings to count to describe it?

Pi, for mathematicians, is essentially a reminder of humility: You’d be surprised how often mathematics and science boils down to “We have no idea how the hell this actually works, but it does!” And it’s also a reminder that no matter how much we quantify and analyze the world around us, there’s much we have yet to comprehend.

In short, Pi Day is fundamentally a celebration of the endless quest for human advancement: Our desire to know more, understand more, be more. And it’s also an excuse to eat pie!