The Grainger College of Engineering, Physics
3/12/2015
Yulia Maximenko
“A lot of people are celebrating Pi Day on March 14, 2015 at 9:26 am. (This makes sense, of course, only if you put the month before the day when you write your date.) But let us not forget that π (the ratio of a circle’s circumference to its diameter) is not actually constant in non-Euclidean geometry. And since we live on a two-dimensional spherical surface, this might actually make a difference for circles much smaller than we would intuitively might have guessed.
Now, some fun facts: for a circle of radius 1000 miles, the value of “π” would be around 3.10867! For a 50 mile radius, “π” would be 3.14151. And even the engineers who built the Large Hadron Collider should have worried about the value of “π”, since for a circular structure 2.7 miles in radius (which is the case for the LHC) “π” would be 3.141592415! So, we strongly encourage all high energy physicists and their sympathizers to celebrate Pi Day two minutes earlier than the rest of the world to honor our non-Euclidean geometry! As for the community of general relativity… we encourage them to redo all the calculations in a non-minkowskian metric for a non-massless Earth to know exactly when they should celebrate Pi Day. “