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## Happy Pi Day218

Posted by Soulskill
from the because-we're-nerds dept.
mikejuk writes to let us know that today is Pi Day — 3/14 in American date notation. He writes, "This year, it feels as though we aren't celebrating alone. For the first time, it looks as if momentum has built up to the point where people have heard about Pi Day. There are even attempts to sell you Pi-related items as if it was a real holiday. But there is always some one to spoil the party so what ever you do to celebrate don't miss Vi Hart's Anti-Pi Rant video." Thus begins the yearly debate over Pi Day vs. Tau Day (June 28). Phil Plait has a post defending Pi Day's honor, and MIT isn't holding back their Pi Day celebrations.
Large-scale celebration of Pi Day began in 1988, mostly through the efforts of physicists Larry Shaw and Ron Hipschmann at the San Francisco Exploratorium. The Exploratorium still runs Pi Day events 26 years later, including Pi-themed processions and pie for dessert. In 2009, Pi Day became semi-official through a vote by the House of Representatives. (They did a better job with Pi than did Indiana, who almost legislated it to be 3.2.)

The best way to celebrate Pi Day is to get together with some friends and talk math over a pie. You could even go for a pizza pie, since a pizza with radius 'z' and height 'a' has volume = pi * z * z * a. If you'd care for a game, head over to the Pi Day Challenge, which features a series of pi-related logic puzzles. Or just spend the day learning about pi.

Cool pi facts: Pi is currently known to about 10 billion decimal places. You can calculate pi using the Fibonacci sequence. A few years ago, Steven Rochen mapped the digits of pi to musical notes and turned it into a violin solo (video). Others have made music from pi as well. Mankind didn't know the first hundred digits of pi until the year 1701. How many digits of pi can you recite? The record for memorization currently stands at 67890 digits. The record for reciting pi while juggling three balls is just under 10,000.
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## Happy Pi Day

• #### I cant buy Pi day greeting cards..... (Score:2)

SO therefore it is not a real holiday...

Damn it Hallmark, we demand Pi day greeting cards!

• #### Re: (Score:2)

Surely there are cards out there that say "Thinking of you" that show a big slice of pie on the front.

• #### Re: (Score:2)

I want 3.14 pieces of it.

• #### Re: (Score:2)

I want 3.14 pieces of it.

If you measure in radians, that is exactly half.

• #### Re: (Score:2)

Even so, it's more of a holiday than Tau day. You can't eat a tau, but you can certainly eat pi(e)!

• #### Tauism (Score:3)

The tau that can be eaten is not the true Tau [wikiquote.org].
• #### Re: (Score:2)

The tau that are eaten become the true Tau [wikia.com].

• #### Re: (Score:2)

I wonder how many serious papers actually use tau instead of pi...

• #### Re: (Score:2)

You can't eat a tau,

There are Tyranids that would disagree with that statement.

• #### Re: (Score:2)

And the area of a unit circle is pi, not tau.

• #### Re:I cant buy Pi day greeting cards..... (Score:4)

on Friday March 14, 2014 @10:38AM (#46483295)
This is my one-year anniversary. The beauty if marrying an engineer is she didn't bat an eye when I suggested getting married 3/14 at 1:59 PM.
• #### How about defining an epoch from pi day? (Score:3)

I always thought that the epoch on a computer should be measured from something like March 14, 1592 @ 6:53:59am (3.14159265359)

Or January 6, 1803 @ 3:9:8am (golden ratio)
Or Feb 7, 1828 @ 1:8:28am (e)
etc

• #### Re: (Score:2)

Month-Day-Year format is irrational. Year-Month-Day, or Day-Month-Year is what you want, with Year-Month-Day being preferred.
• #### WHOOOSH! (Score:2)

Month-Day-Year format is irrational.

Explain to me any part of our date or time system that is actually rational. Months are inconsistent lengths, the number of seconds in a minute or minutes in an hour or hours in a day or days in a week is an arbitrary divisor, the SI unit of time (second) is arbitrary, the year is based on the birth of a mythical religious figurehead, etc ad nauseum. Because we insist on keeping time based on rotations of our planet and orbits of the sun we jump through all sorts of contortions to keep the calendar in syn

• #### Re: (Score:2)

So we should use a format that makes no sense because the rest of the system makes no sense? In every other taxonomy we progress from largest group to the smallest, or from the smallest to the largest. Only in dates do people start in the middle.
• #### Re: (Score:2)

Not really. It would be common to say on march 3rd 1980 something happened. Its more condensed then saying on the 3rd of march, 1980 something happened.

• #### Re: (Score:2)

It doesn't matter how you SAY it. What matters is how you WRITE it, and unless you write it in an unambiguous format, you are not communicating fully or properly.
• #### Re: (Score:2)

No offense, but I think you are missing the significance of Epoch time in thinking this. Even if you stated something like "math is related to computing" the number systems are different. Base 10 vs. Base 2 and all that.
• #### Re: (Score:2)

Only if you ignore all the computers and calculators from befor electronics. Yes, i mean the people that used to fill calculation rooms and compute complexed math problems for sales drones, business processes, and loan officers.

Its not like the term computer was born in the 70s.

• #### Re: (Score:2)

Epoch has nothing to do with any of those things.
• #### Re: (Score:2)

Exactly which is why the GP's point is just as valid as any in base 10 or base 2. Its an arbitrary point of reference.

• #### Re: (Score:2)

I believe you are lost. Try reading the whole comment again and ponder. It's really not that complex.
• #### Re: (Score:2)

Pi day greeting cards [zazzle.com]. No, not from Hallmark, but you can still buy them.

• #### Pi + Einstein + Life, The Universe, and Everything (Score:5, Interesting)

on Friday March 14, 2014 @10:14AM (#46482993)

Not only is today Pi day, but it is Albert Einstein's birthday also (he would've been 135 today). Also, 3 * 14 = 42 so today is also the answer to Life, The Universe, and Everything!

• #### Rest of World (Score:5, Funny)

on Friday March 14, 2014 @10:19AM (#46483069)
In the rest of the world, Pi Day is approximately 22/7.
• #### Re: (Score:2)

I was going to guess it's the third day of whatever month comes after Smarch.

• #### Re:Rest of World (Score:4, Insightful)

on Friday March 14, 2014 @10:47AM (#46483443)

Pretentious! Just as the Americans.

http://en.wikipedia.org/wiki/D... [wikipedia.org]

If you use the notation dd-mm, you'd get a mere 15 (22-7).

• #### Re: (Score:2)

To very few of us it's "Happy 4 * atan(1) Day!"
• #### Re: (Score:2)

It's merely American Pi Day to the rest of the English-speaking world. The real Pi day isn't until the 31st of April.

• #### bought a piece of pie this morning (Score:3, Funny)

on Friday March 14, 2014 @10:19AM (#46483079) Homepage Journal

tasted like chalk dust. how'd math professors get a holiday, anyway?

• #### 3/14/15 (Score:5, Interesting)

on Friday March 14, 2014 @10:28AM (#46483183)
...will make a even better PI day next year...
• #### Re: (Score:2)

Not for the countries that don't use that date format. I wonder if people celebrated pi day back in 3/14/1592. :P

• #### Re: (Score:2)

PI isn't wrong. They just think there's a better way to calculate the dimensions of circle. You can still use PI and it will still be correct.

• #### PI! (Score:5, Informative)

on Friday March 14, 2014 @10:38AM (#46483311)

3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59230 78164 06286 20899 86280 34825 34211 70679 82148 08651 32823 06647 09384 46095 50582 23172 53594 08128 48111 74502 84102 70193 85211 05559 64462 29489 54930 38196 44288 10975 66593 34461 28475 64823 37867 83165 27120 19091 45648 56692 34603 48610 45432 66482 13393 60726 02491 41273 72458 70066 06315 58817 48815 20920 96282 92540 91715 36436 78925 90360 01133 05305 48820 46652 13841 46951 94151 16094 33057 27036 57595 91953 09218 61173 81932 61179 31051 18548 07446 23799 62749 56735 18857 52724 89122 79381 83011 94912 98336 73362 44065 66430 86021 39494 63952 24737 19070 21798 60943 70277 05392 17176 29317 67523 84674 81846 76694 05132 00056 81271 45263 56082 77857 71342 75778 96091 73637 17872 14684 40901 22495 34301 46549 58537 10507 92279 68925 89235 42019 95611 21290 21960 86403 44181 59813 62977 47713 09960 51870 72113 49999 99837 29780 49951 05973 17328 16096 31859 50244 59455 34690 83026 42522 30825 33446 85035 26193 11881 71010 00313 78387 52886 58753 32083 81420 61717 76691 47303 59825 34904 28755 46873 11595 62863 88235 37875 93751 95778 18577 80532 17122 68066 13001 92787 66111 95909 21642 01989 38095 25720 10654 85863 27886 59361 53381 82796 82303 01952 03530 18529 68995 77362 25994 13891 24972 17752 83479 13151 55748 57242 45415 06959 50829 53311 68617 27855 88907 50983 81754 63746 49393 19255 06040 09277 01671 13900 98488 24012 85836 16035 63707 66010 47101 81942 95559 61989 46767 83744 94482 55379 77472 68471 04047 53464 62080 46684 25906 94912 93313 67702 89891 52104 75216 20569 66024 05803 81501 93511 25338 24300 35587 64024 74964 73263 91419 92726 04269 92279 67823 54781 63600 93417 21641 21992 45863 15030 28618 29745 55706 74983 85054 94588 58692 69956 90927 21079 75093 02955 32116 53449 87202 75596 02364 80665 49911 98818 34797 75356 63698 07426 54252 78625 51818 41757 46728 90977 77279 38000 81647 06001 61452 49192 17321 72147 72350 14144 19735 68548 16136 11573 52552 13347 57418 49468 43852 33239 07394 14333 45477 62416 86251 89835 69485 56209 92192 22184 27255 02542 56887 67179 04946 01653 46680 49886 27232 79178 60857 84383 82796 79766 81454 10095 38837 86360 95068 00642 25125 20511 73929 84896 08412 84886 26945 60424 19652 85022 21066 11863 06744 27862 20391 94945 04712 37137 86960 95636 43719 17287 46776 46575 73962 41389 08658 32645 99581 33904 78027 59009 94657 64078 95126 94683 98352 59570 98258 22620 52248 94077 26719 47826 84826 01476 99090 26401 36394 43745 53050 68203 49625 24517 49399 65143 14298 09190 65925 09372 21696 46151 57098 58387 41059 78859 59772 97549 89301 61753 92846 81382 68683 86894 27741 55991 85592 52459 53959 43104 99725 24680 84598 72736 44695 84865 38367 36222 62609 91246 08051 24388 43904 51244 13654 97627 80797 71569 14359 97700 12961 60894 41694 86855 58484 06353 42207 22258 28488 64815 84560 28506 01684 27394 52267 46767 88952 52138 52254 99546 66727 82398 64565 96116 35488 62305 77456 49803 55936 34568 17432 41125 15076 06947 94510 96596 09402 52288 79710 89314 56691 36867 22874 89405 60101 50330 86179 28680 92087 47609 17824 93858 90097 14909 67598 52613 65549 78189 31297 84821 68299 89487 22658 80485 75640 14270 47755 51323 79641 45152 37462 34364 54285 84447 95265 86782 10511 41354 73573 95231 13427 16610 21359 69536 23144 29524 84937 18711 01457 65403 59027 99344 03742 00731 05785 39062 19838 74478 08478 48968 33214 45713 86875 19435 06430 21845 31910 48481 00537 06146 80674 91927 81911 97939 95206 14196 63428 75444 06437 45123 71819 21799 98391 01591 95618 14675 14269 12397 48940 90718 64942 31961 56794 52080 95146 55022 52316 03881 93014 20937 62137 85595 66389 37787 08303 90697 92077 34672 21825 62599 66150 14215 03068 03844 77345 49202 60541 46659 25201 49744 28507 32518 66600 21324 34088 19071 04863 31734 64965 14539 05796 26856 10055 08106 65879 69981 63574 73638 40525 71459 10289 70641 40110 97120 62804 39039 75951 56771 57700 42033 78699 36007 23055 87631 76359 42187 31251 47120 53292 81918 26186 12586 73215 79198 41484 88291 64470 60957 52706 95722 09175 67116 72291 09816

• #### Re: (Score:2)

This is incomplete.
• #### Re: (Score:2)

At least you know how to copy and paste
• #### Re: (Score:2)

If you need more than about 32 digits for your calculations, you grossly misunderstand something.

Second, that's not a factorial.

• #### Re: (Score:2)

If you need more than about 32 digits for your calculations, you grossly misunderstand something.

Actually, there is a practical limiting factor to the number of digits of Pi you actually need for calculations. 39 digits will get you the circumference of the observable universe within 1 hydrogen atom difference [numberphile.com]. That is, the approximation of the circumference of the observable universe when compared versus using more digits of pi, the difference is smaller than the size of a hydrogen atom. (The approximation

• #### Re:PI! (Score:4, Insightful)

<[ten.3dlrow] [ta] [ojom]> on Friday March 14, 2014 @12:38PM (#46484755) Homepage

I think you will find that pi! is actually ~7.18808272898.

TL; DR.

• #### Re: (Score:2)

This is impressive. Unfortunately, you're off by a factor 2.
• #### Radians are wrong (Score:2)

If you want to use pi, then you should be using the angle subtended by the length of the diameter, not the radius, as the basis of your angle measurements. Be consistent.
• #### Re: (Score:2)

If you want to use pi, then you should be using the angle subtended by the length of the diameter, not the radius, as the basis of your angle measurements. Be consistent.

The reason why radians are what they are is because then the length of the arc (of a unit circle) that subtends the angle R is exactly R. That's really convenient. (You could use diameter, but in real work you've got the radius far more often than the diameter.)

And any other ratio (especially tau!) doesn't satisfy the Eulerian identity, so can't be nearly so beautiful.

• #### Re: (Score:2)

The reason why radians are what they are is because then the length of the arc (of a unit circle) that subtends the angle R is exactly R.

Yes, and how many radians are there in a circle? Tau.

And any other ratio (especially tau!) doesn't satisfy the Eulerian identity, so can't be nearly so beautiful.

e^i*tau=1 [youtube.com] seems a lot more beautiful than e^i*pi=-1 to me. It gets rid of that ugly minus one.

• #### Re: (Score:2)

e^i*tau=1 [youtube.com] seems a lot more beautiful than e^i*pi=-1 to me. It gets rid of that ugly minus one.

e^{\pi i} + 1 = 0 includes all "fundamental" numbers without doing anything redundant like 1+0, so arguably it is more beautiful.

• #### Re: (Score:2)

Pi isn't fundamental. It is Tau/2.
• #### ISO 8601 (Score:2)

I will take this opportunity to complain about the American way to write dates, which is pretty stupid, as it's neither big-endian or little-endian and leads to massive confusions for any day numbered 12 or less.

ISO 8601 makes perfect sense as dates are represented in a big-endian format, like all other human-readable numbers (One thousand two hundred and thirty four is 1234, not 4321).

I perfectly understand those who prefer little-endian dates (I used to until I learned of ISO 8601), but have a strong dist

• #### Re: (Score:2)

I also hate when people use slashes or dots to write dates.

• #### Re: (Score:2)

That's far less horrible, though. At least the meaning isn't hard to decipher.

• #### Re: (Score:2)

Yes, this and putting the dollar/currency sign before the number. Some people, including the people in Quebec put the dollar sign after the number. Which makes a lot more sense, if you think of the $(or other currency) as the units of measurement. Plus, it's the way we say it when read. We don't say "I have dollars 2". We say "I have 2 dollars" so it should be written 2$.
• #### Re: (Score:2)

That one really bugs me too. Currency is a unit, units are to be placed after the least significant digit.

• #### Re: (Score:3)

No no, it makes sense to base pi day on American date notation. After all, pi also is irrational!
• #### Re: (Score:2)

I prefer ISO 8601 format because it's easy to sort and I use it all the time. On my bills it's spelled out like you would say it March 14th, 2014 at the top and the line items are in ISO 8601 format. My power bill is the one exception, but it's confusing all around not just the date format. We are moving away from the MMDDYYYY format that everyone outside the US appears to hate, at least in some areas.

• #### Re: (Score:2)

Here's a quick comparison:

Fields in the correct position: European: 1; American: 0
Fields in the correct order: European: 0; American: 2

By that measure the American style gets two things correct; twice as many as the European.

In addition, when the year is omitted (very common), the results are even more striking:

Fields correctly ordered and placed: European: none; American: all.

I don't think anyone has anything to brag about here, except perhaps the Chinese and Japanese. :)

• #### Better in hexadecimal (Score:2)

You can calculate any arbitrary digit of pi in hexadecimal without calculating the preceding digits [hmc.edu].
• #### Steak and BJ day (Score:4, Informative)

on Friday March 14, 2014 @12:05PM (#46484327)

It also happens to be Steak and BJ day...
http://www.officialsteakandblo... [officialst...jobday.com]

• #### Pi Still Correct (Score:2)

As much as I've enjoyed Vi Hart's videos in the past, the whole tau movement always struck me as a bit of a hipster attempt to convert a system that works fine as it is.
Yes, tau makes some of the more basic equations simpler, but it also makes some of the more complex equations messier when compared to pi.
http://www.thepimanifesto.com/ [thepimanifesto.com]

• #### Re: (Score:2)

Yes, tau makes some of the more basic equations simpler, but it also makes some of the more complex equations messier when compared to pi.
http://www.thepimanifesto.com/ [thepimanifesto.com]

Often though, the "simpler" equation with the pi in it is masking the more illustrative tau/2 that arises from the structure of the relationship. The reason that the area of a circle is (1/2)(tau)(r^2) due to the same type of integration that gives us (1/2)(m)(v^2) for kinetic energy or (1/2)(k)(x^2) for energy of a spring for example.

The fact that 2pi appears so very often in math and physics is a strong indication that it is a more "fundamental" quantity.

If anything helps a larger fraction of the student

• #### Ridiculous (Score:2)

3/14 is Steak and Blowjob day.
• #### pi is first letter in greek periphereia (Score:2)

Means a circular line. Root of English word periphery. Mathematicians used the word peripheria, then abbreviated its first letter to describe the length of a circle.
• #### Pi day is next year (Score:2)

Pi day should be next year: 3/14/15 at 9:26:53.58 ...
• #### SXSW (Score:2)

No mention of the smoke trails left in the sky by 5 planes writing out the digits of pi at SXSW yesterday? Given, they were a day early, but it was still freaking amazing!

• #### pizza and pi (Score:2)

If you eat pie today, you will increase your circumference by 2*pi*dr.

And if the volume of a pizza of radius z and thickness a is pi*z*z*a, and its density is p, and the Earth's mass times the gravitational constant is u and its distance from the center is l, the force pulling on that pizza is pi*z*z*a*p*u / l*l.

• #### Just over 364 days to prepare for the big one! (Score:3)

<wwoodhull@gmail.com> on Friday March 14, 2014 @07:52PM (#46488935) Homepage Journal

Next year's Pi Day will make all other Pi Days any of us will experience pale in comparison. For it will be

3-14-15!!?!

Not only that, but it will contain TWO Pi minutes! The first at 9:26 in the morning, and the second at 9:26 in the evening.

.

So it is not yet too late to begin preparing for the momentous events. But do not delay! These precious minutes will never come around again!

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