Not Every 4 Years is a Leap Year

That is TRUE and ABSOLUTELY right! There is 365 days, 5 hours, 48 minutes and 45 seconds that makes up a year in the Gregorian Calendar which most of the world currently uses. This is why we have every 4 years a LEAP YEAR. Actually there is also a LEAP SECOND but that is another story.

SO LET US DO THE MATH AND SEE WHY THERE IS NOT A LEAP YEAR EVERY FOUR YEARS

WAIT, this looks to complicated, so let me just explain why.

Let’s start from the beginning. Who invented leap year? The answer is Julius Caesar over 2,000 years ago. The Julian Calendar, which was named after him, had only one rule, which was any year evenly divisible by four would be a leap year. But because the length of the solar year is actually 365.242216 days, the Julian year was too long by .0078 days. And in the year 1582, the vernal equinox fell on March 11 instead of March 21. Since the equinox was tied to the celebration of Easter, and because the Catholic Church didn’t like so much drift in the date of Easter, Pope Gregory XIII adjusted the calendar by moving the date ahead 10 days and put in this new rule of divisibility by 400 for leap years, thus forming the Gregorian Calendar which is now commonly used.

But the first leap year in the modern sense was in Britain in 1752, when 11 days were ‘lost’ from the month of September with the adoption of the Gregorian calendar by Britain and her colonies. So it was February 29, is the date that was adopted that would usually occur every 4 years, and is called leap day. This day is added to the calendar in leap years as a corrective measure, because as previously mentioned the Earth doesn’t orbit the sun in precisely 365 days.

The next time we will skip a LEAP YEAR will be the year 2100, which means the last leap year of the 21st century will be the year 2096. The year 2100 will be skipped and the next leap year after that will be the year 2104. Well why is that.

(SO WHAT IS THE MATH TO DETERMINE A LEAP YEAR)

To determine whether a year is a leap year, follow these steps:

  1. If the year is evenly divisible by 4, go to step 2. …
  2. If the year is evenly divisible by 100, go to step 3. …
  3. If the year is evenly divisible by 400, go to step 4. …
  4. The year is a leap year (it has 366 days).
  5. The year is not a leap year (it has 365 days).
You will love this video with Neil Degrasse Tyson explaining how it works

If you loved this article, please share as you will discover as maybe yourself that most people have no idea how the leap day was created and even more fascinating that a leap day really does not happen every (4) four years

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