## 03/14/2019 – Ephemeris – Happy Pi Day

Ephemeris for Pi Day, Thursday, March 14th. Today the Sun will be up for 11 hours and 49 minutes, setting at 7:47, and it will rise tomorrow at 7:55. The Moon, at first quarter today, will set at 4:09 tomorrow morning.

Pi day: the first three digits of the mathematical constant π is 3.14 the ratio of a circle’s circumference to its diameter, so March 14th is Pi day. Why do we use the Greek letter pi? Pi is the first letter of the Greek word perimetros which means circumference. The first Pi Day was celebrated in 1988, organized by Larry Shaw at San Francisco’s Exploratorium. There are other lass known pi related days on the calendar. The fraction used in pi approximations is 22/7ths. So July 22nd is Pi Approximation Day. In many formulae π is multiplied by two, or 2π. 2π to two decimal places is 6.28, so it’s Two Pi Day or Tau (τ) Day, June 28th. So whether you like apple, cherry, or pumpkin, have a happy Pi day. https://www.piday.org/pi-facts/

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

### Addendum

Check out https://www.piday.org/pi-facts/ for more information on pi.