Happy Leap Year
Friday, February 29th, 2008Our Solar year is 365.24219 days, tracked on the Gregorian Calendar. Not a nice round number so every four years, we need to tack on an extra day to the shortest month of the year to keep the calendar aligned.
Today is February 29th.
Historically, the Romans originally had a 355 day calendar. To keep up with the seasons, an extra 22 or 23-day month was inserted every second year, or so. They were not consistent in adding this month and by Julius Caesar’s time, the seasons no longer occurred at the same calendar periods as in the past. To correct this, Caesar eliminated the extra month and added one or two extra days to the end of various months. Thus extending the calendar to 365 days. He also intended an extra calendar day every fourth year (following the 28th day of Februarius). However, after Caesar’s death in 44 B.C., the calendars were written with an extra day every 3 years instead of every 4 until corrected in 8 A.D. So again, the calendar drifted away from the seasons.
By 1582, Pope Gregory XIII recognized that Easter would eventually become closer and closer to Christmas. The calendar was modified again so that a leap day would occur in any year that is divisible by 4 but not divisible by 100 except when the year is divisible by 400. Thus 1600 and 2000, although century marks, have a Leap Day.
We use the Gregorian calendar to this day. Our year of 365.2425 days, is only off from our solar year by .00031, which amounts to only one day’s error after 4,000 years.
More at wikipedia.