Leap Year

Leap Year is a concept in the calendar system that refers to a year containing one additional day in order to keep our calendar year synchronized with the solar year or astronomical year. This extra day is added because the Earth does not orbit around the sun in exactly 365 days.

Overview

A leap year occurs every four years to help synchronize the calendar year with the solar year, or the length of time it takes Earth to complete its orbit around the sun, which is about 365.25 days. To account for the 0.25 days that are not covered by our standard 365-day calendar, an extra day, February 29, is added to the calendar every four years.

History

The concept of a leap year has been around since ancient times. The Julian calendar, introduced by Julius Caesar in 46 BC, was the first to include a leap year. The system was later refined in the Gregorian calendar, which is the most widely used calendar system today.

Leap Year Rules

There are three criteria that must be taken into account to identify a leap year:

1. The year can be evenly divided by 4;
2. If the year can be evenly divided by 100, it is NOT a leap year, unless;
3. The year is also evenly divisible by 400. Then it is a leap year.

This means that the year 2000 was a leap year, although 1900 was not.

Leap Year in Medicine

In medicine, the leap year can have implications for those born on February 29. For example, the timing of certain medical screenings and treatments may be based on a patient's age, so a person born on February 29 may have their screenings or treatments scheduled differently.

See Also

• Calendar
• Julian calendar
• Gregorian calendar

This calendar related article is a stub.