From Wikipedia, the free encyclopedia
Year evenly divisible by 400
A
century leap year
is a
leap year
in the
Gregorian calendar
that is evenly
divisible
by 400.
[1]
Like all leap years, it has an extra day in February for a total of 366 days instead of 365. In the obsolete
Julian calendar
, all years that were divisible by 4, including end-of-century years, were considered leap years. The Julian rule, however, adds too many leap days (about 3 extra leap days in 400 years), which resulted in the calendar drifting gradually with respect to the astronomical seasons. To remedy this,
Pope Gregory XIII
introduced in 1582 a slightly modified version of the Julian calendar, the
Gregorian calendar
, where century years are leap years only if they are divisible by 400. This eliminates 3 of the 4 end-of-century years in a 400-year period. For example, the years 1600, 2000, 2400, and 2800 are century leap years since those numbers are evenly divisible by 400, while 1700, 1800, 1900, 2100, 2200, 2300, 2500, 2600, 2700, 2900, and 3000 are
common years
despite being evenly divisible by 4. This scheme brings the average length of the calendar year significantly closer to the astronomical length of the year, nearly eliminating the drift of the calendar against the seasons.
The Gregorian calendar was introduced in 1582, but was adopted by various countries at different times over several centuries. Dates prior to 1582 are generally recorded using the Julian calendar, and different countries have different conventions about how to record dates between 1582 and their
adoption of the Gregorian calendar
.
[a]
Consequently, for example, the year 1700 was a leap year in the British and Russian empires but not in most of the rest of Europe; 1800 and 1900 were still leap years in the Russian empire but not generally elsewhere.
[b]
Notes
[
edit
]
References
[
edit
]
- ^
"Introduction to Calendars"
.
United States Naval Observatory
. n.d
. Retrieved
9 May
2022
.
Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is.
External links
[
edit
]