If, like me, you’re wondering why the month of February felt like it dragged by just a little bit slower, you may be surprised to learn that it’s not just any February – 2024 is a leap year.
According to NASA, leap years happen because of a “mismatch between the calendar year and Earth’s orbit.” Ideally, a calendar year should be the same as a solar year, which is the number of days it takes for the Earth to revolve around the sun. Scientists typically round this to 365, however, it actually takes a little longer – 365 days and six hours – for a complete cycle. Therefore, to accommodate for the extra six hours, every four years, we add an extra day (24 hours, or six times four) to the calendar.
Leap years are essential in ensuring that the calendar year matches the solar year. Subtracting six hours from a year may not seem all that important but if you continue taking hours off, there can be major consequences.
For example, July is typically a sunny and warm summer month. If we never had leap years, though, those missing hours would accumulate into days, weeks and eventually months. Eventually, in a couple hundred years, July would actually be a part of the winter months and we would be celebrating Independence Day donning puffer jackets and mittens.
The concept of a leap year dates back to the ancient Roman calendar, introduced by emperor Julius Caesar in 45 B.C.E. Inspired by the Egyptians, whose solar calendar had 365 days and an extra month for astronomers to observe the stars, Caesar used the same format, but took away the extra month, instead adding a day to every fourth year. Caesar’s calculation, though, was an overestimation which led to an extra eight days per one thousand years. In the 16th century, Pope Gregory XIII addressed this with his Gregorian Calendar – what we use today – adding leap days in years divisible by four.
If you happen to be born today, Feb. 29, that doesn’t mean you only celebrate a birthday every four years. On years without leap days, your birthday would default to March 1 and you would continue to grow old just like anyone else.
