Leapin' Intercalation!!

Taken from the February 6th edition of Red Eye: some interesting numbers relating to the leap year.

365

This is the "typical" number of days in a year, the number of days it takes Earth to travel around the sun, but we all know it's a bit off..

365.25

This is closer to how long it really takes.

45 B.C.

This is the year the Julian calendar was introduced. It didn't take long for the ill effects of the uncounted quarter-days to be noticed: feasts and celebrations seemed to get later and later. So the Julian calendar added a "leap day" to the end of February every four years to even things out. That didn't work out right either. Why?

365.242216

The real number of days it takes Earth to travel once around the sun. It's a little less than exactly 365.25. So the Julian calendar was adding too much time. How much?

11m 45s

That's by how much. So over the centuries, this extra time started to add up again, and again, the calendars were off...

1582

Introduced under the rule of Pope Gregory XIII, the Gregorian calendar added another level of detail: instead of just adding a leap day every four years, there was the additional caveat. A century year would only be a leap year if it was divisible by...

400

... so unless the century can be evenly divided by 400, it's not a leap year. So 2000 was a leap year, but 2100 ain't gonna be. Sounds kinda arbitrary? It works out well though!

365.2425
(or 365 days, 5 hours, 49 minutes and 12 seconds)

The average length of the calendar year using the Gregorian reform we use today.

Additional detail:
10 days: The number of days "lost" when switching from the Julian to the Gregorian calendar. For example, Spain, Portugal and most of Italy jumped from Thursday October 4th 1582 to Friday 15th October 1582.

I remember this being a vital plot point in some tale I read a long time ago, where someone had promised his soul/life to a witch/devil on his Xth birthday, which happened to fall on October 5th 1582, but what with the change in calendars, he never officially had a birthday that year, so he was under no obligation to surrender it. Anyone know about this tale, or similar? I'd like to look it up...

Anyways... this whole issue of correcting man-made calendars to correspond to "reality" ... and by reality in this case I mean if something happened in the height of summer that we want to mark for some reason, it makes sense that we mark it time and time again at the height of summer, right???? The Chinese, the Jews, their lunar calendars correct for the 11-day "drift", the Muslims' doesn't.

I'd moaned about it here previously. This time, I thought to look to Wikipedia, and whaddaya know, I finally got some answers! The practice of adding a day, week or month to a calendar to "correct" it is called intercalation, and it was used in the pre-Islamic Arab calendar. However, insertion of an intercalary month was somehow used to manipulate the occurance of "forbidden (to fight)" months (I'm still unclear about the *why* of this manipulation), so then word came down that "the year has 12 months, so there!".

Fine. So no intercalary month allowed.

Eh. I still have a problem with it.

I have two main thoughts about all this:

One is that by "releasing" the Muslim calendar from the solar seasons, Muslims are then put in touch with the cool / left side of the subtle system , which would have done a lot to literally cool down the overheated right sided folk that they probably were at that time. (Those with any exposure to yoga / subtle systems will know what I mean)

Or two, the interdiction was a knee-jerk reaction to the manipulation of the calendar, without much thought about the consequence of said interdiction (and that has *so* many implications that I can't talk about....). Or two-point-one that the consequence of the 11-day drift was minor, inconsequential even, in the eyes of God, in the whole scheme of things. Doesn't quite sit right with me either way.

I won't expand on the above, but I wonder, does anyone have other thoughts on this subject?

Aaanyways, that was one major digression, but let me get back to the original topic:

HAPPY LEAP DAY!

ciao! :-)