Keeping Time By Earth's Rotations Is Really Messy

Happy 2008 Leap Year Day, when that extra day gets squeezed in to the calendar to fix the discrepancy between the planet's dance and our puny attempt to quantify it.

By the middle ages the western civilizations's Julian calendar was so out of whack with the seasons of the year that something had to be done. Since religious dudes held the most sway back then, pope Gregory VIII finagled with Ceasar's leap year fix by declaring that century years are only leap years if they are divisible by 400, rather than 4. So, the years 1600AD and 2000AD were leap years, but 1700, 1800 and 1900 were not. It made the calendar a little closer to astronomical reality, and won't have to be tweaked for several thousand years.

In order to fix the slow slippage of the seasons though, ten days of the calendar were removed in 1582. A myth started that peasants rioted with pitchforks screaming "give us back our time!" and it seems that never happened, but it's repeated as fact like people believing the world was flat or that Iraq had WMDs. What's interesting was that protestant countries refused to recognize the papal bull so that it must have been quite the circus in international relations. The British colonies didn't adopt the new calendar until 1752 so september looked like this:

By that time eleven days had to disappear for it to work. It created a good deal of confusion. "In the era after the change, dates were written with O.S. (Old Style) or N.S. (New Style) following the day so people examining records could understand whether they were looking at a Julian date or a Gregorian date. While George Washington was born on February 11, 1731 (O.S.), his birthday became February 22, 1732 (N.S.) under the Gregorian calendar." Off course with our penchant for floating holidays that doesn't really matter. When China agreed to use the Gregorian calendar in october of 1949, most of the world was finally on the same page.

And we really don't want to get into leap seconds.

"Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute."