szökévnek

A szökév, or leap year, is a calendar year that contains an extra day, February 29th, making it 366 days long instead of the usual 365. This practice is implemented to keep the calendar year synchronized with the astronomical year, or the time it takes for the Earth to orbit the Sun. The Earth's orbit is not exactly 365 days; it's approximately 365.2422 days. Without the addition of a leap day, the calendar would gradually drift out of sync with the seasons.

The Gregorian calendar, the most widely used civil calendar, follows a specific set of rules for determining leap years. A year is a leap year if it is divisible by four. However, years divisible by 100 are not leap years, unless they are also divisible by 400. For example, 2000 was a leap year because it is divisible by 400, but 1900 was not a leap year because it is divisible by 100 but not by 400. This refined system, introduced by Pope Gregory XIII in 1582, provides a highly accurate approximation of the tropical year.

The concept of adding an extra day to account for the Earth's orbital period has ancient roots, with earlier calendars also attempting to reconcile this discrepancy, though often with less precision. The current leap year system ensures that the solstices and equinoxes remain at roughly the same calendar dates each year, which is crucial for agricultural cycles and other time-sensitive events. The next leap year will be 2028.