Ten Missing Days

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A year is 365 days long, right? Well, not exactly. Sometimes, like this year, the year is 366 days long. This happens every four years, on years divisible by 4. You already knew that, right?

Did you know that some years which are divisible by 4 are NOT leap years?

A little history will explain:




In 46 BC, Julius Caesar created what's known as the Julian calendar. It had 365 days per year, except every four years there was an extra day added in February. Just like today, right? Almost.

Though this gives an average year-length of 365.25 days, the year is actually a little bit shorter, about 11 minutes shorter. This adds up to three fewer days every 400 years, which means that in a 400 year span, there needs to be only 97 leap days, not 100 as the Julian calendar prescribes.

By 1582 AD, the calendar had drifted 10 whole days away from its proper date, which was screwing up the proper day on which to celebrate Easter, not to mention the seasons showing up at the wrong time. So Pope Gregory the 13th created something called called a papal bull, which is basically a decree for the whole world.

Of course, back then, as now, something less than the whole world paid attention to the Pope's decrees, but the Catholic world did pay attention, so that Thursday, October 4th was followed by Friday, October 15th. Ten days had to be skipped in order to get the calendar back on track, but at the time, only a handful of countries observed the change.

Over the years, more countries adopted the change until finally, the last Christian countries to do so, Russia and Greece, did so in the early 20th century and had to skip 13 days. (The October Revolution occurs in November because at the time, Russia was still on the Julian calendar.)

This new calendar, dubbed the Gregorian calendar, follows a slightly different rule than the Julian calendar. Every four years a leap day is added, UNLESS the year is divisible by 100... UNLESS the year is divisible by 400. So 1900 would normally have been a leap year, but it actually wasn't. However, the year 2000 WAS a leap year because it's divisible by 400. When we get to 2100, it will NOT be a leap year, nor will be 2200 or 2300, but 2400 will be.

Neat, huh?

If you plan on living that long, you'll see for yourself.

Here's some fascinating history of the Julian calendar and the Gregorian calendar.

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