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Leap Years etc.

Henry Best (mka John Strauss) wrote:

JS> Of course, Ponte Alto is not actually entitled to have a Birthday 
JS> until next year, as their investiture was February 29th.

True enough. This is the Baronial UNbirthday event....

JS> I am looking forward to Ponte Alto's FIRST Baronial Birthday in '96.
JS> They should make it a pretty big shindig, as it will be their first and
JS> they won't get a second one until 2004.

Corwyn (Mario M. Butter) then pointed out:

MB> The second one will be in 2000. 2000 is also a leap year.

So Kendrick (Tanner Lovelace), Carole (Carole Stoops), Tadhg (Chuck Graves)
and Michael (Mike Adnrews) all contended that 2000 is not a leap year:

TL> ***bzzzt***  Sorry, but thank you for playing.  The year 2000
TL> is not a leap year.  Every now and then they have to skip one
TL> to get things back on track.  (Anyone want to better explain it?)

CS> Leap years occur in all years divisible by four EXCEPT when the year ends 
CS> in a double zero.  The year is not exactly 365 days and 6 hours long; it 
CS> is slightly less, so we need a leap day slightly less often.  (There is 
CS> also a leap second occasionally, when needed.)

CS> I did a science project on timekeeping back in sixth grade, which was 
CS> when I learned all this stuff.  It was really a history of science 
CS> project, but they okayed it.  I made a sundial, water clock, sand clock, 
CS> did some pendulum experiments, etc., and had flats explaining Daylight 
CS> Savings Time, leap years, etc.

CG> We have a leap year every four years...except on millennia The cycle of
CG> our sun requires we add one day every four years and subtract one day
CG> every thousand. Great system, eh.

MA> Kendrick is right. The rule is (more or less) that years which
MA> are divisible by 4 and not by 400 are leap years; there is (IMSC)
MA> an additional correction tossed in even less frequently than
MA> every 400 years, but I'm switched if I can remember it.

But none of these are precisely correct. When the Gregorian calendar reform
was instituted in 1582 (yes it's period) the RC Church was enlightened
enough to use the best science they could find to calculate the actual length
of the year. The resulting system was correctly described by Landi:

LF>    Now the version of the story that I heard was that century years evenly
LF> divisible by _400_ _were_ leap years (1700, 1800, and 1900 were not, 2000
LF> will be).  If I'm wrong, blame it on Old-Timer's Disease.  :-)

Add one day every four years: leap year.
Then subtract one day every hundred years: century year.
Then add one back every four hundred: leap century.
That's how we were taught (Central Catholic HS, Allentown PA, History of
  the Catholic Church - great course).

LF>    Of course the real question is:  When is the next time February 29th
LF> falls on Saturday?

The solar cycle is every 28 years, except when non-leap centuries get in the
way. Thus add 28 to 1992 and get 2020 as the date of the next One True Feast
Day of Saint Pyr. (The previous one was in AS minus 2 or minus 3, CE 1964.
That's the day I was brought home from the hospital after being on the
receiving end of birth.)

Get out the duck shoes and umbrellas, Rencesterites -- the Charter Day
tradition continues. The North Wind doth blow, and Washington gets snow,
but for Williamsburg the forecast is RAIN.

Evan da Collaureo, heading for Rencester this weekend.