The Novice Writer: The Leap Year Explained!!

LEAP YEAR EXPLAINED!

Introduction:

A leap year, also known as an intercalary year or bissextile year, is a calendar year containing one additional day or, in the case of lunisolar calendars, a month added to keep the calendar year synchronized with the astronomical or seasonal year. Because seasons and astronomical events do not repeat in a whole number of days, calendars that have the same number of days in each year drift over time with respect to the event that the year is supposed to track. By inserting also called intercalating an additional day or month into the year, the drift can be corrected. A year that is not a leap year is called a common year.

For example, in the Gregorian calendar, each leap year has 366 days instead of the usual 365, by extending February to 29 days rather than the common 28. These extra days occur in years which are multiples of four (with the exception of years divisible by 100 but not by 400 - See the algorithm below).

Similarly, in the lunisolar Hebrew calendar, Adar Aleph, a 13th lunar month, is added seven times every 19 years to the twelve lunar months in its common years to keep its calendar year from drifting through the seasons. In the Bahá'í Calendar, a leap day is added when needed to ensure that the following year begins on the vernal equinox.

The name "leap year" probably comes from the fact that while a fixed date in the Gregorian calendar normally advances one day of the week from one year to the next, the day of the week in the 12 months following the leap day (from March 1 through February 28 of the following year) will advance two days due to the extra day (thus "leaping over" one of the days in the week). For example, Christmas Day (December 25) fell on a Monday in 2017, then it will fall on Tuesday in 2018, and Wednesday in 2019 but then "leaps" over Thursday to fall on a Friday in 2020.

The length of a day is also occasionally changed by the insertion of leap seconds into Coordinated Universal Time (UTC), owing to the variability of Earth's rotational period. Unlike leap days, leap seconds are not introduced on a regular schedule, since the variability in the length of the day is not entirely predictable.

Some Facts:

In 1627, during the Anglo-French War, the English army invaded a French Island on the 12th of July but the French army was ready to defend on the 22nd of July. This did not matter because those were the same day because French and English had a different calendar that had different approaches towards "LEAP YEAR" and hence due to the calendar drifts this problem had occurred. But both countries agreed that it was a Thursday.

February 29 is a date that usually occurs every four years, and is called leap day. This day is added to the calendar in leap years as a corrective measure because the Earth does not orbit the sun in precisely 365 days.

1 year = 365 days 5 hours 48 minutes 45 seconds 138 milliseconds.

If you consider a year to be 365 days long then after every 4 years you will see a drift of one day in it.

If you consider a year to be 365.25 days long then after every 128 years you will see a drift of a day.

If you consider a year to be 365.2425 days long then after every 3216 years you will see a drift of a day.

Algorithm:

The following pseudocode determines whether a year is a leap year or a common year in the Gregorian calendar. The year variable being tested is the integer representing the number of the year in the Gregorian calendar, and the tests are arranged to dispatch the most common cases first.

*Care should be taken in translating mathematical integer divisibility into specific programming languages.