Re: February 30th 2000

[David Malone]

On Fri, Jan 14, 2000 at 09:06:00AM +1300, Chris Wedgwood wrote:
> > Our current (gregorian) rules come to 
> > 
> > 	365 + 1/4 - 1/100 + 1/400 = 365.2425
> > 
> > The difference with 365.24219878 is: .00030122, which means that every
> > 3320 years or so, we're having one too many leap years. So, I would
> > suggest that we make the year 3300 a leap year. And 6600, 9900, 13300
> > and so on.... (*)
> 
> Years evenly divisible by 4000 are _not_ leap years. I only know of
> one (nay, two shortly) piece of code which take this into account...

2.2.2. Isn't there a 4000-year rule?
------------------------------------

It has been suggested (by the astronomer John Herschel (1792-1871)
among others) that a better approximation to the length of the
tropical year would be 365 969/4000 days = 365.24225 days. This would
dictate 969 leap years every 4000 years, rather than the 970 leap
years mandated by the Gregorian calendar. This could be achieved by
dropping one leap year from the Gregorian calendar every 4000 years,
which would make years divisible by 4000 non-leap years.

This rule has, however, not been officially adopted.

	David.