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 ...... ----------------------------------------------------------------------- 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! ----------------------------------------------------------------------- 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? =========================================================================== "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!chuck
ndiamond@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