Wednesday, February 29, 2012

Happy Leap Day!

It's Leap Day!... or, February 29th. I don't know about you, but I find having a bonus day kind of exciting!

Here are some fun facts about Leap Years:

2012, as well as all leap years, consists of 366 days, as opposed to 365. Leap Years are needed to keep our calendar in alignment with the Earth's revolutions around the sun. It takes the Earth 365 days, 5 hours, 48 minutes, and 46 seconds (a tropical year) to circle once around the Sun. However, the Gregorian calendar (ours) has only 365 days in a year, so if we didn't add a day on February 29 about every 4 years, we would lose almost six hours off our calendar every year. That means that after only 100 years, our calendar would be off by approximately 24 days!

Leap years can't just be decided at random though! In the Gregorian calendar, there are 3 criteria that must be met to be a leap year:

1. The year must be evenly divisible by 4.
2. If the year can be evenly divided by 100, it is NOT a leap year, unless...
3. The year is also evenly divisible by 400. Then it is a leap year.

Don't worry if this doesn't make sense. Someone's already done all the work for us, but did you have any idea there was so much behind it? I sure didn't!

Julius Caesar introduced Leap Years in the Roman empire over 2000 years ago, but the Julian calendar had only one rule: any year evenly divisible by 4 would be a leap year. This lead to way too many leap years, however this issue didn't get corrected until the introduction of the Gregorian Calendar more than 1500 years later.

So, that leaves one more question...where does the word "leap" come in to play? This is another complicated explanation but in a normal sequence of years, a calendar date (say February 28th) falls on Monday one year, Tuesday the next year, then Wednesday the year after that and so on. But every fourth year, thanks to the extra day in February, we "leap" over the expected day of the week. So February 28th was a Monday last year, a Tuesday this year, and will be a Thursday in 2013. We "leaped over" Wednesday! Get it?

Happy Leap Day! Enjoy the extra 24-hours!

1 comment:

Copyright 2009 Laura Druda