It takes 365 days, 5 hours, 49 minutes, and 16 seconds for the Earth to make one revolution around the sun. Since our calendar is based on a 365-day year, we squirrel those extra hours away in a lock box and create an additional day every four years or so*. Today is just such a bonus day, more commonly called Leap Day. What will you do with your extra day? I’m making a pot roast. 🙂
*To accomodate the slight inaccuracy of rounding up the 5 hours, 49 minutes, and 16 seconds to equal a 24-hour bonus day, there is an additional qualifier for whether or not a year is a leap year: not only does it have to occur in a year that is evenly divisible by 4 (such as 2012), years that mark a new century (such as 1900, or 2000) must also pass one additional qualifier: they must be evenly divisible by 400 in order to get a leap day. Under this additional calculation, 1900 did not have a leap day, but 2000 did.