pumphrey@ttidcb.UUCP (Larry Pumphrey) (02/14/85)
HI KIDS!!! It's time for another bedtime story from Uncle Pac-Man.
Tonight's enchanting tale is called "The Pope and the Calendar." It
begins in a rather ordinary way, once upon a time in a papalcy far,
far away ......
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History: Julius Caesar imposed a calendar of exactly 365.25 days per
year in 46BC which is to say that *every* fourth year was a
leap year. This calendar is known as the Julian calendar.
Fact: The solar year is 365.24219878 days in length (at least it
was in 1900). The fact is that the solar year becomes shorter
by about 5 milliseconds every year, but more on this later.
History: The differences between the Julian and solar years left a
~.0078 day error every year. Needless to say, after 1500+
years (the year 1 AD is recognized as the baseline year for
all calendar references) this error accumulated to almost one
fortnight. This caused some serious problems in regard to
when to plant and harvest crops, etc. However, a very grave
problem arose within the church; Easter was about to occur
before Jewish Passover. {Maybe this discussion should be in
net.religion :-)}. To prevent this calamity from occurring,
Pope Gregory XIII called in his council of Astronomical Advisors
and said, "Hey guys, we got a problem that can't be stonewalled.
We've got a calendar deficit of 12 days and it's growing at
the rate of almost 8 millidays every single year! This one
has to be fixed during my administration." Well, the council
went off and studied this problem and came back with a supply-
side calendar theory which they presented. First of all, they
said that every man, woman and child owed the calendar twelve
days. Now even though the Pope promised before his election
that he would ask for no increase in time; he was convinced that
this measure was necessary in order to prevent double-digit
intercalation which, of course, would affect the young and the
old alike as well as the yet to be born! Secondly, this grace
commission proposed that by streamlining the calendar, then
any excess days in the future would be allowed to trickle down
to the populace on an accrual basis. _Old_ Pope Gregory was
finally sold on this new calendar and presented it to the world
in 1582 as his Strategic Decimal-point Initiative. It was at
once accepted in those countries containing majorities of his
own party. The opposition parties in certain other countries
such as Britain and colonial America eventually adopted Greg's
calendar in 1752. The press of the day jokingly referred to
all of this hocus-pocus as Gregonomics but as it all began to
*really* work, the technocrats won out and called it as we know
it today --- the Gregorian calendar.
Fact: The Gregorian calendar has 365.24225 days per year. It accom-
plishes this by having a uniform rule with 3 orders of
exception.
Uniform rule: All years consists of 365 days, except
1st exception: Any year divisible by 4 has 366 days, except
2nd exception: Any year divisible by 100 has 365 days
unless also divisible by 400, in which case
it has 366 days, except
3rd exception: Any year divisible by 4000 has 365 days
Everybody knows the uniform rule and the first exception.
Most people {except _some_ netters, :-) } know of the second
exception; however, few people are aware of the third exception.
If only the first 2 exceptions are adopted the Gregorian calendar
would contain 365.2425 days which produces a ~.3 milliday error.
This would accumulate to 1 day every 3300+ years. Thus the 3rd
exception provides for a Gregorian year of 365.24225 days which
results in a 50 microday error per year. Fourth and higher
order exceptions are unnecessary as 50 microdays is in the noise
level when compared with errors produced in the solar year by
earth motion phenomena such as axis wobble, rotation slowdown,
orbit decay, etc. These errors were referred to earlier.
It should be pointed out that one netter alluded to the 4000
year exception but couldn't remember exactly what it was.
Another netter suggested looking this all up in any basic
book on Astronomy. However, this third order exception is
seldom found in astronomy books (basic or advanced) simply
because the length of a civil (calendar) year is of little
astronomical interest. However, the rule can frequently
be found in almanacs and some of the better encyclopaedias
(try Britannica).
Result: The year 4000 is _not_ a leap year.
Task: Don't waste your time fixing those 2000 AD calendar bugs gang,
because all your files will disappear in the year 4000 anyway!
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And that boys and girls is the tender and heart-warming story of how
to fit a digital calendar to an analog equinox. Until next time,
this is Uncle Pac-Man leaving you with this thought to ponder ---
Does a Pythagorean triple constitute a menage a trois? If so, who
plays the role of the hypotenuse?
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"Please support the Jacobians in their struggle for independence"
(Uncle Pac-Man @ Citicorp TTI; Santa Monica, CA)
===========================================================================chuck@dartvax.UUCP (Chuck Simmons) (02/18/85)
Dear Uncle Pac-Man,
Loved your posting on how to figure out when leap years occur.
But I thought I'd bitch about one small paragraph:
> Fact: The Gregorian calendar has 365.24225 days per year. It accom-
> plishes this by having a uniform rule with 3 orders of
> exception.
>
> Uniform rule: All years consists of 365 days, except
> 1st exception: Any year divisible by 4 has 366 days, except
> 2nd exception: Any year divisible by 100 has 365 days
> unless also divisible by 400, in which case
> it has 366 days, except
> 3rd exception: Any year divisible by 4000 has 365 days
>
This is actually a uniform rule with 4 exceptions. No doubt you
purposely destroyed the symmetry of the result to make a subtle pun
about uniformity and exceptions.
Oh well... wonderful posting. Do it again sometime.
dartvax!chuckndiamond@watdaisy.UUCP (Norman Diamond) (02/18/85)
> HI KIDS!!! It's time for another bedtime story from Uncle Pac-Man. > ----------------------------------------------------------------------- > Uniform rule: All years consists of 365 days, except > 1st exception: Any year divisible by 4 has 366 days, except > 2nd exception: Any year divisible by 100 has 365 days > unless also divisible by 400, in which case > it has 366 days, except > 3rd exception: Any year divisible by 4000 has 365 days My understanding was that only one country in the world has adopted the rule with all three exceptions, and that we in the "free world" break the law if we apply the third exception! -- Norman Diamond UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!watdaisy!ndiamond CSNET: ndiamond%watdaisy@waterloo.csnet ARPA: ndiamond%watdaisy%waterloo.csnet@csnet-relay.arpa "Opinions are those of the keyboard, and do not reflect on me or higher-ups."
ags@pucc-i (Dave Seaman) (02/18/85)
> Fact: The Gregorian calendar has 365.24225 days per year. It accom- > plishes this by having a uniform rule with 3 orders of > exception. > > Uniform rule: All years consists of 365 days, except > 1st exception: Any year divisible by 4 has 366 days, except > 2nd exception: Any year divisible by 100 has 365 days > unless also divisible by 400, in which case > it has 366 days, except > 3rd exception: Any year divisible by 4000 has 365 days I count three exceptions and one "unless." Apparently the 400-year rule is a second-order exception (All the exceptions are exceptions except the 400-year exception). -- Dave Seaman ..!pur-ee!pucc-i:ags