Every four years, the Gregorian calendar grants one extra day for people around the world to enjoy: February 29th. A leap year is known to occur on the years that are divisible by four; some examples are the years 2016, 2020, and 2024. However, leap years are tricky to calculate because not all years that are divisible by four are leap years. The discrepancy behind the phenomena is for historical, mathematical, and scientific reasons.
Some are informed that there are a total of 364 days in a year and 24 hours in a day. However, not many know that it takes the Earth 364.24 days to orbit the sun, which is the reason why the leap year was established in the calendar year. This indicates that our calendar is off by about a quarter of the year. This was noticed in 45 B.C. by Julius Caesar, a former Roman dictator. In order to get rid of the discrepancy, Caesar added an extra day every four years to make up for the difference. This solution was inspired by the Egyptians and their calendars. Caesar’s solution didn’t completely fix the calendar, though. Caesar had miscalculated the solar year to be about 11 minutes longer, leading to an extension of about eight days per millennium. This wouldn’t have been a problem if the solar year was exactly 364 ¼ days, but 364.24 is slightly less than that, according to AP News. By 1582 A.D., those days added up to a total of 10 days, making the past calendar no longer reliable. This is an unignorable problem because in about 700 years, the agreed summertime in the northern hemisphere would occur in December, messing up the seasonal timeline and the living patterns of humans.
Pope Gregory XIII fixed this small problem and created the new Gregorian calendar, creating the term “leap year” to describe the years where there was an extra day per year. An extra day is added to the end of the month, creating a new day, February 29th, during February in the respective leap years. Due to the pope’s change, a leap year occurs during the years that are divisible by four, but not in century years that are divisible by 400. Without a leap year, one would lose six hours from the calendar every four years. Leap years contribute to the astronomical alignment with the Earth revolving around the sun. It’s crucial to note that even this compromise doesn’t work perfectly as the solar year is still currently 26 seconds shorter than the Gregorian year, as stated by CNN News.
Leap day was decided to be in February because it was already the shortest month of the year with only 28 days. Originally, the designated leap day was on February 24th because the ancient Romans disliked odd numbers, rejecting the notion that leap day should be on February 29th. As as explained by NPR, people eventually shifted leap day to February 29th because of the confusion that February 24th caused. This is because despite leap day being on the 24th, it created a push so that February would still be 29 days either way.
Strangely, leap day customs influence marriage culture in different countries for unknown reasons. There is an ancient folktale that says that in 5th-century Ireland, women weren’t allowed to propose to men, but one day every four years, on February 29th, women were able to propose to men. Thus, leap day became also known as Bachelor’s Day. On the other hand, in Greece, it is considered bad luck to marry on Leap Day, another interesting fact about leap day.
Now, the million-dollar question everyone wondered whilst reading: “What about people whose birthdays are on February 29th?” Those people are referred to as “leaplings,” and there are “5 million people globally that were born on leap day, with the odds being 1-in-1,461,” History.com reported. Just because one’s birthday only comes once every four years doesn’t mean that it’s forgotten. Ultimately, people just celebrate it on February 28th or March 1st instead.
Leap year contributes to the global understanding of seasons and when they’re expected to start. By creating leap days every four years, the seasons successfully match the calendar, even though it may still be slightly altered with new solutions in many years to come. With its infrequent appearance in the calendar, leap year continues to serve as a source of curiosity to many.
