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magnificent*
31-03-2005, 02:06
We all know about leap years but I want to know how many people can explain why we have them? I am also interested if people understand why later on they had to adjust the calender by 11 days because it was decided that leap years should not occur on the turn of the century even though dates like 1900 are multiples of 4. Incidently 2000 was a leap year but the change of milenium is an exception to the exception.

m1s1n
31-03-2005, 02:18
Because we like to find reasons to laugh at people. Especially those that only have a birthday every four-years. This way the only cake they really get to cherish are at the celebration of others.

Adept
31-03-2005, 02:24
Simply because it takes 8766 hours for earth to orbit the sun, but the calendar year only has 8760 hours in it. So, after a while, we would be getting (depending on your hemisphere) Christmas in winter. Which wouldn't really suck, but it would make planning things in advance that much harder. So we added in an extra calendar day every four years to even things out.

inquisitorkane
31-03-2005, 03:35
Exactly. Each orbit actually takes 365.25 (give or take a few minutes) days, so every 4 years we have to add on an extra day to make sure things are all caught up.

As for why they dont occur on the turn of the century, well, I dont really know, but I would hazzard a guess it's something superstitous. But then, there might be a scientific reason for it.

Sojourner
01-04-2005, 07:37
Even then it isn't quite right. The turn of the year drifts a few seconds every orbit. So we're going to have to have a leap century sometime.

Sgt John Keel
01-04-2005, 08:22
As for why they dont occur on the turn of the century, well, I dont really know, but I would hazzard a guess it's something superstitous. But then, there might be a scientific reason for it.

Because the year actually is about 365.2425 days long. By skipping every century except millennias, you get a more accurate calendar.

/Adrian

Sai-Lauren
01-04-2005, 11:08
Right.
As said earlier, the orbit of the earth around the sun takes slightly more than 365.25 days, although a day is actually something like 23 hours and 56 minutes.

A leap year occurs if the year is divisible by 4, except for centuries, when the first two digits have to be divisible by 4 - so the next century leap year will be 2400.
There are occasional leap seconds put in to adjust for various discrepancies. Unless you're running an atomic clock, your timepiece is not really accurate enough to bother with this kind of variation.

Delicious Soy
02-04-2005, 02:07
The problem with atomic clocks though, is that they have to be adjusted every so often because they are more accurate than the Earths orbit when measuring time.

inquisitorkane
02-04-2005, 05:28
Because the year actually is about 365.2425 days long. By skipping every century except millennias, you get a more accurate calendar.

/Adrian

Ah, well, there you go. Scientific reason for everything. Well, most things.

HalberdBlue
02-04-2005, 12:19
Everything you ever wanted to know about leap years, leap centuries, and leap seconds:

http://www.boulder.nist.gov/timefreq/general/leaps.htm