Saturday, March 14, 2015

Today Is A Once-in-One-Hundred-Years Day!

My husband and his celebratory T-Shirt!

Today is a special day, especially for mathematicians. Can anyone tell me why?
Sorry I can’t wait for an answer. Today is Pi π day! And not just here, but all over the world!
Now folks, this is a big deal as it only happens once in one hundred years. Putting it that way, I realize my Dad didn’t see one of these. The last one happened in 1915 and he wasn’t born yet. And he died two years ago, so he isn’t here to see this one. But I am, and almost everyone else I love, and I think that’s pretty cool. 
Never-ending story...

Yep, I'd eat this "pi"

My husband has this on a t-shirt

Now, what does Pi day mean, exactly? Well, there is a “Pi” day every year, celebrating the first three digits 314. But this year Pi day is different, and much more special. Not being a math head myself, my husband explained it to me this way. It means that today, March 14, 2015 at exactly 9:26.53 am, is the only day/time in one hundred years where we will find the first ten decimals from the equation “Pi” in our date/time line. The first ten numbers (decimals) of Pi are 3141592653, which, as you can see can be the date 3/14/2015 (March 14, 2015) and time of 9:26.53 am. I guess it could be at nine pm, unless one is using the 24 hour clock.
A funny pi...

This is how Wikipedia explains it. “In the year 2015, Pi Day will have special significance on 3/14/15 at 9:26:53 a.m. and p.m., with the date and time representing the first 10 digits of π. That same second will also contain a precise instant corresponding to all of the digits of π. However, some argue that 9:26:54 a.m. and p.m. on 3/14/15 are more accurate because of the 11th digit of π being 5, which would cause the 10th digit to round up to 4.”
Use of Pi

I don't get it, but another use of Pi

I like the way my husband explained it better…

Next year we will only find five, the year after that, nothing, nada, not for another one hundred years will this happen again. So go ahead, celebrate! Enjoy the brief moment in history when you actually saw/lived through something as cool as a solar eclipse, or turn of the century. You are living history. Cheer on your moment of glory!

Right now the Pi equation is over 1 trillion (that is 1billion millions) and still going. That means, if you were to write them one after the other, at standard font, say font 11, they would stretch from earth past the moon, and going! I wonder how far our mathematicians/computers will be in the π equation in another hundred years…
Evidently, the sky is not the limit!

For more information:

And look what they're doing to celebrate it in France!

Images from:


  1. Perhaps Pi is simply infinity.

  2. Hi Lisa .. how fascinating .. I hadn't heard of this at all .. so I will be back to re-read and no doubt the story will feature in the papers too ... and elsewhere ... there are films out too ... maths ones. Congratulations to your hubby with his T-shirt ... I might look for some of those ...

    Must go - got to leave early ... brilliant post - cheers Hilary

  3. Anonymous8:40 AM

    Thank you for your thorough explanation! I knew my kids were celebrating Pi Day at school, but I didn't realize the once-in-a-hundred-years significance. That's really neat! I think some Pie is definitely in order this weekend.

  4. I learned this fun fact today, and had fun with it, even though I forgot to pay attention at 9.26.53.

  5. There were a lot of great Pi post on Facebook yesterday! :)

  6. I should have read this yesterday. My nerdy kids were all about pi day yesterday.

  7. This Pi Day is much deeper than I'd thought. Of course, I missed it. And I happen to like Pie. :-)


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