Year 2000 leap year? -Reply 
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 Year 2000 leap year? -Reply

From:   http://www.***.com/
(US Naval Observatory Time Service Department)

Leap Years

The Rule

According to the Gregorian calendar, which is the civil calendar in use today, years evenly
divisible by 4 are leap years, with the exception of centurial years that
are not evenly divisible by 400. Therefore, the years 1700, 1800, 1900 and 2100 are not
leap years, but 1600, 2000, and 2400 are leap years.

Background

The Gregorian calendar year is intended to be of the same length as the cycle of the
seasons. However, the cycle of the seasons, technically known as the tropical
year, is approximately 365.2422 days. Since a calendar year consists of an integral number
of whole days, a calendar year cannot exactly match the tropical year.
If the calendar year always consisted of 365 days, it would be short of the tropical year
by about 0.2422 days every year. Over a century, the calendar and the
seasons would depart by about 24 days, so that the beginning of spring in the northern
hemisphere would shift from March 20 to April 13.

To synchronize the calendar and tropical years, leap days are periodically added to the
calendar, forming leap years. If a leap day is added every fourth year, the
average length of the calendar year is 365.25 days. This was the basis of the Julian
calendar, introduced by Julius Caesar in 46 B.C. In this case the calendar year
is longer than the tropical year by about 0.0078 days. Over a century this difference
accumulates to a little over three quarters of a day. From the time of Julius
Caesar to the six{*filter*}th century A.D., the beginning of spring shifted from March 23 to
March 11.
When Pope Gregory XIII instituted the Gregorian calendar in 1582, the calendar was shifted
to make the beginning of spring fall on March 21 and a new system
of leap days was introduced. Instead of intercalating a leap day every fourth year, 97 leap
days would be introduced every 400 years, according to the rule given
above. Thus, the average Gregorian calendar year is 365.2425 days in length. This agrees to
within a half a minute of the length of the tropical year. It will take
about 3300 years before the Gregorian calendar is as much as one day out of step with the
seasons.

When Pope Gregory XIII instituted the Gregorian calendar in 1582, the calendar was shifted
to make the beginning of spring fall on March 21 and a new system
of leap days was introduced. Instead of intercalating a leap day every fourth year, 97 leap
days would be introduced every 400 years, according to the rule given
above. Thus, the average Gregorian calendar year is 365.2425 days in length. This agrees to
within a half a minute of the length of the tropical year. It will take
about 3300 years before the Gregorian calendar is as much as one day out of step with the
seasons.

Is the year 2000 a leap-year?  I know this has been hashed over many times but I was
wondering if any decision was "officially" made.  The way it looks, Informix Online
7.12.UC1 allows the date "02/29/2000" to be entered into the system.  Any news greatly
appreciated.

TIA,
Kevin Knight
Schwan's Sales Enterprises



Wed, 18 Jun 1902 08:00:00 GMT
 
 [ 1 post ] 

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