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Happy Pi Day

Tomorrow is an extra special, up-to-the-second Pi Day. How special? Once a century special!

What is Pi Day? It is a day celebrating mathematics held on March 14 every year. In the US at least, we write this date as 3/14, corresponding to the first three digits of Pi (3.14).

But once a century we get an extra special treat. Tomorrow’s date is 3/14/15, which corresponds to the first 5 digits of Pi (whoo hoo!).

And if you are a real nerd like me, you also get to celebrate “Pi Second” at 9:26:53. That is a mind-blowing 10 digits of Pi!!! 3.141592653 And we get to do it twice, once in the AM and once in the PM.

If that weren’t enough, tomorrow is also the birthday of Albert Einstein, one of the most famous and brilliant mathematicians of all time. What an amazing coincidence!

How do you celebrate Pi Day? By eating pie (including pizza), marching around circular spaces (and meditating on the fact that walking around a circle takes 3.141592653… times as long as walking across it), memorizing digits of Pi, and marveling at the wonders of mathematics (like infinities) and all the benefits mathematics has brought to us. For example, Alan Turing was a mathematician, and he was largely responsible for inventing the computer.

Back in the 17th century, Ludolph van Ceulen spent his entire life calculating digits of Pi, and only managed to get 35 decimals. Nowadays, using our mathematics-based computers, we have calculated Pi to over 10 trillion decimal places.

That’s a lot of Pi!

UPDATE: MIT takes Pi Day very seriously! This is how they send out their acceptance letters for admission, and they do it on Pi Day.



  1. Xuuths wrote:

    Einstein was a physicist, not a mathematician. Small point. I’ll be quiet and go now…

    Friday, March 13, 2015 at 12:31 pm | Permalink
  2. Iron Knee wrote:

    You have clearly not eaten enough Pi.

    Friday, March 13, 2015 at 9:53 pm | Permalink
  3. ralph wrote:

    Pi is a universal constant and must be known to any other technologically advanced life forms out there. So for many years now, in hopes of contacting an alien civilization, scientists have been repeatedly broadcasting it into deep space, in the form of the well known equation for the area of a circle – “Pi r squared”.

    Remarkably, an alien response has recently been received and translated. “Silly Earthlings. Pi r round.”

    (Cue shaving cream pie in face).

    Saturday, March 14, 2015 at 8:31 am | Permalink
  4. Iron Knee wrote:

    One of my favorite jokes is about a young hillbilly who goes to school where they try to teach him “Pi r squared”, but he refuses to believe it. They ask him why and he says “Pi are round, cornbread are squared”.

    Saturday, March 14, 2015 at 5:06 pm | Permalink
  5. Quidam wrote:

    It is unfortunately only American Pi day
    Since in the rest of the world the month comes in the middle and there will never be a 14 month.

    What to do on American Pi day does also involve a pie, but make sure your folk are out all day before you try it

    Monday, March 16, 2015 at 9:18 am | Permalink
  6. Iron Knee wrote:

    I always write my dates in an unambiguous way. For example, today is “16 Mar 2015”. I’ve never understood why people want to use a number for the month just to save one character (and confuse people).

    Monday, March 16, 2015 at 9:26 am | Permalink