It’s Pi Day!

March 14, 2015 • 9:53 am

Addenda:

Reader Amy wins the Geek Prize for taking a photo of the right time on Pi Day—to the second.  You won’t see this for another 100 years:

pi-day-us-time

And Melissa Chen posted this highly creative Pi Day Act on Facebook:

11012670_1087724611252965_6418273949804471473_n

 

Finally, a tw**t from Neil deGrasse Tyson:

Screen Shot 2015-03-14 at 1.07.42 PM

______

Pi Day means that today’s date (in American usage) is 3/14/15, which is pi to five digits. This won’t happen again for a century. Sadly, I missed by about 30 minutes putting up this post at a time with three more digits that are accurate:

3/14/15 9:26

I’m a bad person.

To make up for that, here’s a teenager reciting the first 100 digits of pi, balancing a book on her head, and solving a Rubik’s cube. This is what we call a “polymath”:

and here’s a 10-year-old reciting 370 digits of pi.

Be sure to mark the day this way (Make mine the Hoosier Mama Pie Company; it took me two years to realize the name was a pun.)

My favorite pies:  Pear cream-cheese pie, cherry pie, lowbush blueberry pie from Helen’s in Machias, Maine, and pecan pie.

 

72 thoughts on “It’s Pi Day!”

    1. I disagree! A bad person would edit the posting date in WordPress to reflect the Pi date. A bad person would withhold drool-worthy pictures entirely. Or, even worse, not post them until we all have full stomachs, at which time the photos would be nowhere near as appealing.

    3. We still have Tau Day to look forward to:

      6/28/31 at 08:53:07

      See also here:

      http://www.tauday.com/tau-manifesto

      And, I’ll have to admit, the proliferation of 2pi in various mathematical places rather than a “whole” constant is something I did notice as I was obtaining my B.S. in math.

  3. It’s only pi day in one country… It’s on the 31st of April everywhere else… Oh hang on, 1st of May, no, that doesn’t work… Err. Carry on.

    3. Oh boy — does that mean we can celebrate two Pi Days. We can haz pie today and again on April 31 —- Yipee. Thanks Charles

  4. Indeed! But next year we can also celebrate something special. On 3/14/16, it will be the correct rounded value to 5 decimal places, closer to the exact value than 3/14/15!

    1. Actually, according to some, 2015 is the most significant year ever! There was a thing called pi instant this year. The digits of time can be represented as an infinite sequence of decimal digits and when the time is just right (not too hot, not too cold) it will equal pi exactly. Take a look at what Jeffrey Rosenthal thinks.

      http://probability.ca/jeff/writing/PiInstant.html</a

      OK now, break out the lemon miringue pie and lets celebrate!

      1. It seems to me that the infinite series wouldn’t be the Pi “instant” but the series that is precise down to a Planck time unit, as I posted in post #11.

        I’m still not clear on whether this means time is discrete or merely meaningless on a scale less than this, but either way it seems we couldn’t have an “instant” anywhere near an infinite series of numbers to the right of the decimal point. Maybe one of the Physicists on this site can help us out here.

  5. My wife is making strawberry rhubarb pie to add to other pies we will be pigging out on with friends later in the day. We will be drinking a PInot noir.

  6. Heh. Someone posted about this on Duolingo. I had no idea what they meant by “pi” day. Thanks for spelling it out. Though I’ve got to say that this makes no sense in the UK where today’s date is 14/03/15.

    1. That’s the date just about everywhere – I’ve never understood the Americans. It’s like telling the time minutes, hours, seconds.

      1. To be fair: although the “rest of the world” is more rational than the barmy US format, to be truly logical, the order should be “year-month-day-hour-min-sec” ie from the largest to the smallest.

        3. That’s the officially correct way to do it in Canada, according to the Federal Gov’t. Most people haven’t paid any attention, beyond the bureaucrats who are required to follow the rule.

          1. The year-month-day way to do it is handy for sorting. At work I put my sets of photos of construction jobs in directories named by date e.g. 20150315 for today, then they all show in sequence automatically when I open the filer.

      3. And that’s what it is in a number of places – Japan does it that way, for example. Also, organizations that keep track of things in a way that can be sorted by date (such as patent offices, but not the US patent office) do too.

        1. When I say “almost everywhere”, it’s the 15th already in NZ, Australia, a few Pacific islands, and some other places.

      4. Americans write it the way they say it, e.g., March, 14, [20]15, that’s all.

    2. YYYYMMDD is certainly the most logical way to do it in computer systems for ease of sorting by date. Sure, format it any way you wish in the display, but please keep the behind the scenes number stored correctly.

      1. As I noted further up in the thread (by position) but later (by posting time). Sorry for the plagiarism…

    1. Oh very good.

      A fascinating walk through mathematical conventions that leaves me with one pressing question –
      did she use every colour of Sharpie in the box?

      😉

  8. It’s 4am – how am I supposed to get back to sleep with visions of wonderful pies in my brain? And one mentioned cheese and chive scones, which I like even more! And I’m still feeling inadequate from the videos – I used to think being able to solve a Rubik’s cube was a good enough trick! Now I’m supposed to do it balancing books and reciting pi! Not that I feel actually feel moved or inspired to attempt such things. Just sayin’.

  9. The sequence of digits of pi after the 762nd is 999999

    This is known as the Feynmam point and there’s a story that he wished he could memorise pi up to that point, so he could recite it and end up saying “999999 and so on”

    …. well I found it amusing

  12. Yay for Pi Day! I think I will celebrate by making a pie. Or I might go out for pizza pie!

  13. I’m not going to complain, since there were apple and cherry pies waiting for us when we returned from our running club workout early this morning.

    Good thing there aren’t pies every Saturday, though – that would counteract much of the running for me.

  15. “Even though the numbers in pi have been calculated to the trillions, it only takes 39 digits to calculate the circumference of the known universe to within the width of one hydrogen atom.”

    3.14159 is good enough for me.

  16. There is an absolutely incredible relationship between Pi and the squares of the prime numbers.
    Pi^2 / 6 = 4/3 * 9/8 * 25/24 * 49/48 * 121/120 ….

    This is crazy! How on Earth could there be any connection between prime numbers and the area of a circle?

    1. That is awesome. I’m sure somewhere in the mathematical proof, the relationship reveals it self beautifully.

      My guess is that it is also related to the fact that the square root of an integer n that is a nonperfect square can be approximated by finding the integers x and y that it falls between, then taking (n – x^2 / 2n). E.g. sqrt(42) is between 6 and 7 and can be approximated by 6 + (42 – (6^2))/(2*6) = 6.5. The fractional portion always falls between x^2/2n and X^2/(2n + 1), so between 6 and 6/12 and 6 and 6/13. As n goes to infinity, the fractional result converges to x^2/2n.

      This is formally shown in a Fourier Series expansion if I remember correctly. Anyhow, the fact that the result has to do with a series of integers squared as well as Pi^2 and my guess is that an expansion of this sort comes into play somewhere. Trying to remember how to even begin showing this formally though is making my head hurt.

    2. Without knowing who first proved that, I’d guess it was Ramanujan – his equations are marvelous.

      1. It was actually Euler. He also proved that the sum of the reciprocals of the squares of the integers is also pi^2 / 6.

  17. The symbol Pi (not the number 3.14 etc.) is also used to represent a measure of nucleotide variation in DNA. Pi is low in regions where an advantageous mutation has spread, sweeping away variation at nearby sites. Pi is higher in regions with a lot of recombination.

    1. She makes PI more romantic than you’d expect:

      “Sweet and gentle sensitive man
      With an obsessive nature and deep fascination
      For numbers
      And a complete infatuation with the calculation
      Of PI

      Oh he love, he love, he love
      He does love his numbers
      And they run, they run, they run him
      In a great big circle
      In a circle of infinity

      3.1415926535 897932
      3846 264 338 3279”

  21. I ran a pi-K this morning. 3.1415 km. the race started 9:26:53 AM. There was pie waiting at the end.

    I could do it all again next week regardless of the date.

  22. Lamentations

    1 King 7v23 has PI=3
    This pretty much sums up the limited standard of thought of the scriptures.
    “He made a Sea of cast metal, circular in shape, measuring ten cubits from rim to rim and five cubits high. It took a line of thirty cubits to measure round it”

    Repeated again in 2 Chronicles 4v2

    This is not the authorship of a creator of a finely tuned universe.
    This is the authorship of a primate with a slightly bigger brain than the other great apes

    Lamentations 1v4 says the priests of Zion groan but as far as I know no author in the Bible moans about the error of making PI=3. No criticism from Jesus, no correction.

    Isaiah 40v22,”He sits enthroned above the circle of the earth”, he pulls the chain and his people receive the turd of god.

    Isaiah 40v14,”Whom did the Lord consult to enlighten him and who taught him the right way?” Well they should be sacked, whoever it was cause PI=3 ain’t close enough.

    1. Re Isaiah 40v12,”with the breadth of his hands marked off the heavens”

      If god’s hands were big enough to be useful for measuring the heavens, and yet god was close enough for the Earth to appear to him as a circle rather than a point of light then we should be able to see these super massive hands. The hands of god should block out the stars beyond, so from this I deduce that the hand’s of god are not only invisible but also see through / transparent.

      Isaiah 40v27, “Why do you complain O Israel,”My way is hidden from the Lord”
      It would have been a decent excuse that God was so far away that the Earth could not be seen due to the glare of the sun: like how astronomers have trouble finding exoplanets around other stars. Thus God didn’t know what was happening on Earth otherwise he would have prevented suffering.

      If god was close enough then the Earth should have appeared as a three dimensional sphere.

      Maybe it is just that god is merely an idol that can be nailed down (Isaiah 41v7)

      The author’s idea of the size of the Earth was limited to the Middle East. Isaiah 41v8-9,”But you, O Israel, my servant Jacob, whom I have chosen, you descendants of Abraham my friend, I took you from the ends of the earth, from its farthest corners i called you” A circle with corners whose circumference divided by diameter = 3 ?
      Obviously babble.

  23. Too bad it’s not a Sunday, or else we could have called it a pious day.
    badabang badaboom…I’ll be here all the veek.

    1. I just noticed that my PI capture is accurate to one additional digit.

      3.1415926536

  25. I like cows. I like All Things Bovinae. I also like film / a passel of most anything movies’ – wise.

    As does Kansan Mr Derek Klingenberg. When Mr Klingenberg isn’t actually .working. cattle, then he is out there with either i) serenading ‘em via his trombone – playing or ii) filming them frolicking and romping in their other activities.

    Because of their noms, of course, and his pickup’s reliable horsepower, the cows “prepared” for his filming their … … Dance To the Pi.

    As in ( yeah, ! wait for it ! ) … … cow – pi: http://www.youtube.com/watch?v=X1hYhU2wLys .

    Blue

  27. “To make up for that, here’s a teenager reciting the first 100 digits of pi, balancing a book on her head, and solving a Rubik’s cube. This is what we call a “polymath”:

    and here’s a 10-year-old reciting 370 digits of pi.”

    As long as they’re doing it of their own volition. In the seventh grade I was required to memorize in alphabetical order the names of all ninety-five counties of my state. I did what I was told. A total waste of cognition, an exercise in state-level narcissism and national-level “exceptionalism.”

      1. Texas has 254 counties, more than any other state. It is number 1 in state-level narcissism though. I see a large number of Texans who are certain that they live in the best place in the world – and have never been anywhere else.

        1. Yup, Tennessee sent hits shar uv Tennesseans to Texas.

          Ah reckon there’s been a bit of tit-for-tat ‘tween TX and TN. Something about The Great Bird of Texas flying over and doing some eschatological something to Tennessee with Tennessee replying and making some equally-blunt reference to cows.

          1. Been that way since that Crockett fella beat a path from TN to TX and met his end at the Alamo.

      2. No, but a kindred spirit to Texas:

        “Born on a mountain top in Tennessee,
        Greatest state in the Land of the Fee,
        Raised in thuh woods so he knew every tree,
        Kilt him a bar, when he was only three.”

  28. That girl with the stack of books was a bit wobbly at times – but awesome! I couldn’t do any of those things, still less for (or in) 42 seconds.

  29. You would think that a god so benign
    Would improve the world’s basic design.
    He could sign a decree
    Making pi simply 3
    Not 3.14159

  31. My Son was asking about digits of Pi. I told him to go ahead and have fun with it; but he didn’t really need to remember more than 3 significant figures of it.

    99.9+% of the time people can’t/won’t measure things more precisely than 1 part per thousand. It’s almost always good enough.

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