======================================================================< Updated 1998 March 31 YEAR 2000 trivia The New Year 2000 is NOT the turn of the century nor of the millenium. Besides the date bug on computers, there is nothing special about 2000 January 1st. It is a known fact that Jesus Christ was probably born around year -7. Thus 2000 years after Christ was around 1993 (others mention 1996?). Too late anyways! And this is only the current christian calendar. Until the 6st century, the Roman Empire was counting since year -753 the date of Rome foundation. Other cultures have other calendars: For Jews we will be in 5760 as they count since 3760 BC, the moment of creation; For Muslims we will be in 1419, as they count since 622 AD, Muhammad's flight to Medina; For Japanese it is the 12th year of Aki Hito; Hindus count from 3102 BC, the beginning of Kali Yuga cycle; The New Year 2000 is NOT the turn of the century nor of the millenium. This is because year 1 AD, instead of year zero was the first year: A 6th century monk, Denys le Petit, proposed Christ birth (or rather the 1st of January of following year) as Year 1, instead of year zero. Thus the 1st century began in year 1 and finished the first day of 101. The 1st millenium began in year 1 and finished the first day of 1001. So scientifically, mathematically and correctly, the 21st century will begin on January 1, 2001 as well as the 3rd millenium. But it seems that the whole world has decided to celebrate the event on December 31, 1999 ... and I will celebrate too! 2000 IS A LEAP YEAR: -------------------- -1- Julian calendar rules: The first leap year rule was defined in 46 B.C. by Julius Caesar to adjust for the length of a solar year, estimated at 365.25 days by Alexandrian astronomer Sosigenes. --> The Julian calendar introduced a February 29th when YYYY is divisible by 4 (like 1996 was a leap year). -2- Gregorian calendar rules: But because the year is not 365.25 but 365.24219 (see note 1), Pope Gregory XIII realized that the calendar was off by 10 days in 1582. --> The Gregorian calendar introduced 4 new rules: a) The Thursday 1582 Oct 4 was immediately followed by Friday Oct 15th. But Protestant England and America didn't change to the new calendar until 1752. By this time the gap was 11 days so the correction was to have Wednesday Sep 2, 1752 followed by Thursday Sep 14. b) The YY00 are not leap years, c) Except if they divide by 400. Thus 1600 and 2000 are leap years, but 1700, 1800, 1900 and 2100 are not. d) The first day of the year was set at January 1st 1752 (It used to be March 25, Annunciation Day). Note 1: This 365.24219 instead of 365 is an error of 11.2 minutes a year, ie 1 day every 128 years thus the 10 days off at Gregory's time. If we examine the 365.24219, each year of 365 days we loose .24 days which is compensated by the Julian leap year rule. But it is .24 not .25 thus an over compensation of .01 days each year, or 1 full day every 100 years (Gregorian Rule b). In addition it is not .24 but .24219 thus we discard .00219 days every year or 1 full day every 400 years (Gregorian Rule c). By the way, the solar year is not exactly 365.24219 but is off by 11 seconds. On the other hand, the earth is gradually speeding up around the Sun, so Gregorian calendar should be right on in 20 000 years from now! WHY JULY and AUGUST both have 31 DAYS and other trivia ------------------------------------------------------ 1 March - Mars, the original beginning of the year. Mars is the Roman god of war. 2 April - Aphrodite, the Greek goddess of love and beauty, the Roman Venus. 3 May - Maia, goddess of spring and wife of Vulcan. 4 June - Juno, the Roman goddess of marriage and the well-being of women, the wife and sister of Jupiter. 5 July - Julius Caesar 6 August - Augustus Caesar Julian calendar renamed the 5th and 6th months Julius and Augustus in honor of their eponyms, and the number of days in August, previously 30 was increased to 31 (the same as in July), so that Augustus would not be considered by later generations to be inferior to Julius Caesar! 7 September - the seventh month. 8 October - the eighth month. 9 November - the ninth month. 10 December - the tenth month. 11 January - Janus, the Roman god of gates and doorways, depicted with two faces looking in opposite directions. 12 February - Februa, the Roman festival of purification. The last day of the year, the 12th month (February) had 28 or 29 days to adjust for leap year. NO YEAR 0 and +-BC notation --------------------------- There was no year 0, meaning that the year 1 AD was the first year and is preceded by the year 1 B.C. In order to avoid a hiatus between the year 0 and the 1 B.C, the astronomers have adopted the following convention: 1 A.D. = Year +1 1 B.C. = Year 0 2 B.C. = Year -1 and so on Thus for astronomers, 13 B.C. is also refered as -12 ! UNIX and year .... 2038 ----------------------- Not all flavors of Unix count time the same way. And we don't even take applications into consideration. AIX counts time as the number of seconds since the "Unix Epoch", ie 00:00:00 1970 January 1. Time is stored as a 32 bit integer, for a total of 2 billion possible seconds thus 68 years, in 2038, at which time, 64 bit Operating Systems should handle the date problem behing the scene (and I should be retired!). The tm_year command gives the number of years since 1900. A clever technique is used in Unix: the date partitioning algorithm. It assumes a leading value of 19 for years in the range 69 to 99 and a leading value of 20 for years in the range 00 to 68. I should be retired before the problem comes back in 2069 ! 1969 was chosen because Unix (and most data processing) did not began before 1969. Some others take 1960. CN and year .... 1962 --------------------- The official CN DATE is now around 13200 (Issue TSO CNTIME) which means that CN start date is 1962 January 1st. So in CN world the switch could be done at year 61/62 instead of 68/69 Marc Merel