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A Brief History of Leap Day
A thrilling history of calendars
Today is leap day. It is a day that most people don’t think much about. February 29th is an oddity that marks presidential election years in the United States and the year of the Summer Olympics in the modern era. There are a large number of babies born on this day every four years that will be bestowed with eye-raising identification cards and a conversation starter for life. But when did leap day start?
Leap day occurs once every four years, inside of what is known as a leap year. In more technical terms, this day is known as an intercalary date. Intercalary dates are added to calendars to ensure that they continue to follow the flow of the astronomical calendar set by the motion of the Earth around the sun.
Most people erroneously believe that a year is 365 days long. A year is actually 365 days 5 hours 48 minutes 46 seconds long. Those extra five hours and forty-eight minutes may not seem like much, but they can actually be problematic. If you do not account for those extra hours every year, the human calendar will start to drift apart from the solar calendar. You would lose a day every four years. That means that after 100 years, the seasons will have shifted to the left. Spring would be summer, summer would be autumn and so on.
