Since 1582, the Gregorian calendar has been gradually adopted as a вЂњcivilвЂќ international standard for many countries around the world. Notice that 2000 was a leap year because it is divisible by 400, but that 1900 was not a leap year. In fact, a solar year occurs over a period of 365.2422 days. This additional correction was added to stabilize the calendar over a period of thousands of years and was necessary because solar years are actually slightly less than 365.25 days. The Gregorian calendar further stated that leap days should not be added in years ending in вЂњ00вЂќ unless that year is also divisible by 400. In 1582, Pope Gregory XIII revised the Julian calendar by creating the Gregorian calendar with the assistance of Christopher Clavius, a German mathematician and astronomer. Leap days were first added to the Julian Calendar in 46 BCE by Julius Caesar at the advice of Sosigenes, an Alexandrian astronomer. This German mathematician and astronomer figured out how and where to place leap years in the Gregorian calendar. You can see that, if even more time were to pass without the leap year as a calendar correction, eventually February would be a summer month in the Northern Hemisphere. ItвЂ™d be off by about 25 days after 100 years. For example, without correction the calendar year would be off by about one day after four years. Over time and without correction, the calendar year would drift away from the solar year. In essence, the calendar year, which is a human artifact, is faster than the solar year, the 365 days 5 hours 48 minutes 46 seconds that our planet requires to orbit the sun once.

25 that creates the need for a leap year every four years.Дuring non-leap years, aka common years вЂ“ like 2022 вЂ“ the calendar doesnвЂ™t take into account the extra quarter of a day required by Earth to complete a single orbit. Our planet takes approximately 365.25 days to orbit the sun once. Why do we need the extra day? Blame EarthвЂ™s orbit. ItвЂ™ll help synchronize our human-created calendars with EarthвЂ™s orbit around the sun, and with the passing of the seasons. So 2024 will be our next leap year, a 366-day-long year, with an extra day added to our calendar (February 29).

Leap year 2020