Approximately every four years, February 29 is added to our calendars and we experience a Leap Year. This has been going on since before we can remember, but do you know just how long that is or why the mysterious extra day is added? Great Plains Communications wants to answer some of your questions and share the interesting history of the Leap Year.
Why Do We Have a Leap Year?
The modern calendar is made up of 365 days a year, but it takes the Earth roughly 365.2421 days to orbit around the sun. A quarter of a day might not seem like much, but over centuries it adds up. According to the History Channel, “To ensure consistency with the true astronomical year, it is necessary to periodically add in an extra day to make up the lost time and get the calendar back in sync with the heavens.”
When Did It Begin?
Originally discovered by the Egyptians, it wasn’t until the reign of Julius Caesar in 14 B.C. that the leap year was brought to Europe. Caesar was the one to change the calendar to 12 months and 365 days. By adding one day every four years, the “Julian Calendar” looked to have found a way to fix the slight inconsistency.
Though, due to the fact that there is a .242 day difference between the solar and Roman calendars, rather than an exactly .25, adding a day every four years leaves a slight surplus of roughly 11 minutes. Doing the math, that would leave Caesar’s calendar off one day every 128 years.
In hope of fixing the error, Pope Gregory XIII revised the calendar in 1582 to the one we use today. As we still recognize the leap year every four years, the adjustment is rather mathematical. “Leap years occur every four years except for years evenly divisible by 100 and not by 400. For example, the year 1900 was not a leap year because it was divisible by 100, but not 400.”¹
- Andrews, Evan. The History Channel. Why do we have leap year? https://www.history.com/news/ask-history/why-do-we-have-leap-year. 2014