# why do we have leap year every 4 years

What Is a Leap Year? Nearly every four years is a leap year which has 366 days, as opposed to a, which has 365 in the Gregorian Calendar. Leap years have 366 days, not 365. We use leap years to sync our common years with the tropical years. When Is the Next Leap Year? Next is. Last was. Why Add Leap Years? Leap years are needed to keep our modern day in alignment with the Earth's revolutions around the sun. It takes the Earth approximately 365. 242189 days Б or 365 days, 5 hours, 48 minutes, and 45 seconds Б to circle once around the Sun. This is called a, and is measured from the. However, the Gregorian calendar has only 365 days in a year, so if we didn't add a leap day on February 29 nearly every four years, we would lose almost six hours off our calendar every year.

After only 100 years, our calendar would be off by around 24 days! Exactly Which Years Are Leap Years? We add a, almost every four years. The leap day is an extra, or intercalary, day and we add it to the shortest month of the year,. If the year can be evenly divided by 100, it is NOT a leap year, unless;

The year is also evenly divisible by 400. Then it is a leap year. This means that in the Gregorian calendar, the years and are leap years, while, , , and are NOT leap years. The year was somewhat special as it was the first instance when the third criterion was used in most parts of the world since the from the Julian to the Gregorian Calendar. Julius Caesar introduced leap years. Roman general Julius Caesar first introduced leap years. бbigstockphoto. com Who Invented Leap Years?

Roman general Julius Caesar introduced the first leap years over 2000 years ago. But the had only one rule: any year evenly divisible by four would be a leap year. This formula produced way too many leap years, but was not corrected until the introduction of the Gregorian calendar more than 1500 years later. The ancient added an extra month every few years to maintain the correct seasonal changes, similar to. Topics:, Why do we need leap year? The calendar, which now serves as the standard calendar for civil use throughout the world, has both common years and leap years. A has 365 days and a leap year 366 days, with the extra, or, day designated as February 29. A leap year occurs every four years to help synchronize the calendar year with the solar year, or the length of time it takes the earth to complete its orbit about the sun, which is about 365 days.

The length of the solar year, however, is slightly less than 365 days by about 11 minutes. To compensate for this discrepancy, the leap year is omitted three times every four hundred years. In other words, a century year cannot be a leap year unless it is divisible by 400. Thus 1700, 1800, and 1900 were not leap years, but 1600, 2000, and 2400 are leap years. What are your chances of being born on leap day? About 1 in 1,500. When is the birthday party? If you are born on a Leap Year, do you get your driver's license on February 28th or March 1st? It is an ambiguous question that is decided by each state. Most states, however, consider March 1st the official day.

For instance, the Michigan Vehicle Code states that people born on February 29th "are deemed to have been born on March 1st. " How many people were born on leap day? There are about 187,000 people in the US and 4 million people in the world who were born on Leap Day. Most years that can be divided evenly by 4 are leap years. Exception: Century years are NOT leap years UNLESS they can be evenly divided by 400. When did leap year originate? The Gregorian calendar is closely based on the Julian calendar, which was introduced by in 45 BC. The Julian calendar featured a 12-month, 365-day year, with an intercalary day inserted every fourth year at the end of February to make an average year of 365. 25 days. But because the length of the solar year is actually 365. 242216 days, the Julian year was too long by. 0078 days (11 minutes 14 seconds).

This may not seem like a lot, but over the course of centuries it added up, until in the 16th century, the vernal equinox was falling around March 11 instead of March 21. In 1582, adjusted the calendar by moving the date ahead by 11 days and by instituting the exception to the rule for leap years. This new rule, whereby a century year is a leap year only if divisible by 400, is the sole feature that distinguishes the Gregorian calendar from the Julian calendar. Following the Gregorian reform, the average length of the year was 365. 2425 days, an even closer approximation to the solar year. At this rate, it will take more than 3,000 years for the Gregorian calendar to gain one extra day in error.

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