# Pi Day 2015

Shortly before 9:27 this morning, it will be 3/14/15 9:26:53. The significance of this moment is, at best, questionable.

Let’s break it down.

The year (AD 2015) is calculated from the birthday of Jesus of Nazareth. However, more recent estimates suggest that he/He was born between 8 BC and 4 BC, as his birth is known to have preceded Herod’s death in 4 BC. So, we should have been celebrating the Millennium somewhere between 1992 and 1996, and the momentous second on which this post is based actually took place between four and eight years ago. So this puts a big question mark over the 15. The fact that we’re ignoring the century (20) is another convenient aside.

The Gregorian calendar was introduced on 24 February, 1582, making it 433 years and 18 days old. It succeeded the ten month Julian calendar, which was slightly inaccurate in its year length. There doesn’t seem to be any logic for there being twelve months (although it’s nice that they divide into quarters, thirds and halves), nor is there any real logic for the first day of the year falling on 1 January. It’s always struck me as odd that it didn’t fall on one of the equinoxes, or else a solstice, given that these dates have a natural beauty. This puts pay to the 3 and the 14.

Now to the time. It’s claimed that the Egyptians were responsible for dividing the day into two twelve-hour chunks, while the Babylonians can claim rights to the 60s used for seconds and minutes. Both are thought to be arbitrary units, chosen more for their mathematical beauty than their worldly significance. So, the 9, 26 and 53 are pretty arbitrary too.

That the UK orders its dates as DD/MM as opposed to MM/DD means that the significance of “International” Pi Day is quashed entirely in the UK, and indeed much of the non-American world. (Much better, I feel, to celebrate it on 22 July, or 22/7.)

So the US will start celebrating the event in just under five hours’ time using Eastern Daylight Time (and will repeat the celebrations at each of three hours thereafter in CDT, MDT and PDT). (Hawaii’s HST will have to wait a further three hours. The islands stopped bothering with daylight saving in 1945.) Daylight time was a concept first proposed by New Zealand’s George Vernon Hudson in 1895, making the rationale for the specific hour of celebration somewhat random.

Happy [International] Pi Day, everyone. #PiDay2015