Today is National Pi Day because the numbers of the day (3-14) match the first three digits for Pi, which is both an irrational and a transcendental number, i.e., the number is not a ratio or a root of any other numbers and the digits in Pi have no pattern (at least in the first few trillion digits). Mathematicians have spent their lives trying to discern meaning in Pi. Carl Sagan’s book (not the movie) Contact dealt with this theme at length where Pi contains messages from ancient beings, and where the main character Ellie gleans some preliminary meanings.

The earliest approximations of Pi by the Egyptians, Babylonians and Indians were fractions, e.g., 22/7, which is close to Pi, 3.14159265358…. The Greeks were famous in their efforts to “square the circle,” i.e., geometrically constructing a square having the same area as a given circle, and asking whether Euclid’s axioms posit the existence of such a number. The Greeks and many others could not do it, which had profound implications to Plato regarding the usefulness of Euclid’s theorems to describe the real world.

To this day, the importance of Pi remains high since the number pervades much of Nature, and mathematicians are still calculating it. Also, people love to recite the digits. Piphilology is study of techniques for people to memorize the digits. The record now is over 100,000. As a mathematics/computer science major, I also memorized Pi – to about 20 decimals.

On a different note, today is also National Potato Chip Day, commemorating the 1853 (or so) creation of this snack. Apparently, there are over 1,500 such “National” days for various things, in addition to national Weeks and Months. Happy Pi Day!

Raymond Van Dyke, Pi enthusiast