Leap Year 2016. It means that we have a February 29th which only is added every 4th year. Why? I ask myself the same thing. I can understand Daylight Savings when we adjust the clock one hour; I can understand the Greek celebration of Easter falling on a different day than the Easter that is on the modern day calandar, but I cannot understand this “Leap Year” concept! I dug deep into the recesses of Google and was surprised to learn some things…….Leap Year is like a tune-up for the calendar much like a tune-up for your car. Leap years are added to the calendar to keep it working properly. The 365 days of the annual calendar are meant to match up with the solar year. A solar year is the time it takes the Earth to complete its orbit around the Sun — about one year. But the actual time it takes for the Earth to travel around the Sun is in fact a little longer than that—about 365 ¼ days (365 days, 5 hours, 48 minutes, and 46 seconds, to be precise). So the calendar and the solar year don’t completely match—the calendar year is a touch shorter than the solar year. Ha! There you go! It may not seem like much of a difference, but after a few years those extra quarter days in the solar year begin to add up. After four years, for example, the four extra quarter days would make the calendar fall behind the solar year by about a day. Over the course of a century, the difference between the solar year and the calendar year would become 25 days! Instead of summer beginning in June, for example, it wouldn’t start until nearly a month later, in July. As every kid looking forward to summer vacation knows—calendar or no calendar—that’s way too late! So every four years a leap day is added to the calendar to allow it to catch up to the solar year.
Julius Caesar was the first to adopt this solution for their calendar, and the Romans became the first to designate February 29 as the leap day.
So do the math…. add an extra day to the calendar every four years to compensate for the extra quarter of a day in the solar year. But the solar year is just close to 365 ¼ days long, but not exactly! The exact length of a solar year is actually 11 minutes and 14 seconds less than 365 ¼ days. That means that even if you add a leap day every four years, the calendar would still overshoot the solar year by a little bit—11 minutes and 14 seconds per year. These minutes and seconds really start to add up: after 128 years, the calendar would gain an entire extra day. So, the leap year rule, “add a leap year every four years” was a good rule, but not good enough! Are you following me?
To rectify the situation, the creators of our Gregorian Calendar decided to omit leap years three times every four hundred years. This would shorten the calendar every so often and rid it of the annual excess of 11 minutes and 14 seconds. So in addition to the rule that a leap year occurs every four years, a new rule was added: a century year is not a leap year unless it is evenly divisible by 400. This rule manages to eliminate three leap years every few hundred years. Are you thinking like me…….who is going to be around to enforce this or even make it relevant 200+ years from now?
At any rate, if you happen to be born on February 29th I hope you celebrate like you haven’t had a birthday in 4 years!!!