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Leap year
I need help. This is a leap year and I know that every 4 years we add a day to Feruary because the earth rotates around the sun at the rate of 365 1/4 days . But I would have sworn that in the year 2000 I heard that when leap year is in the first year of a new century there is not a day added to February as the earth's rotation is really slightly less than 365 1/4 days around the sun. Did I imagine that or does anyone else remember the same thing? 5 comments from 4 users
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posted by
Smokey
on Feb 29, 2008 at 09:50 AM
The exact length of a solar year is actually 11 minutes and 14 seconds less than 365 ¼ days. That means that even if you add a leap day every four years, the calendar would still overshoot the solar year by a little bit—11 minutes and 14 seconds per year. These minutes and seconds really start to add up: after 128 years, the calendar would gain an entire extra day. So, the leap year rule, "add a leap year every four years" was a good rule, but not good enough! To rectify the situation, the creators of our calendar (the Gregorian calendar, introduced in 1582) decided to omit leap years three times every four hundred years. This would shorten the calendar every so often and rid it of the annual excess of 11 minutes and 14 seconds. So in addition to the rule that a leap year occurs every four years, a new rule was added: a century year is not a leap year unless it is evenly divisible by 400. This rule manages to eliminate three leap years every few hundred years. posted by
robertcarter
on Feb 29, 2008 at 10:14 AM
Thank you Smokey - I do appreciate your knowledge. posted by
Smokey
on Feb 29, 2008 at 01:43 PM
Thank goodness for google LOL posted by
oohchild
on Feb 29, 2008 at 02:50 PM
http://www.badastronomy.com... Another one of my favorite websites. Phil gives you all the math you can handle! posted by
madkow2747
on Feb 29, 2008 at 06:28 PM
My favorite misconception headline on Bad Astronomy: "Flushed with Pride: the Coriolis Effect in your Potty"... :)
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