Six takeaways:
- Why do Leap Years occur? Mathematically, the exact length of a year is not 365 days on the dot, but 365.2422 days. That small extra 0.2422 days adds up over time… every four 0.2422 days roughly equal one full day. So every four years, we add one on.
- If we didn’t account for this extra time, the seasons would begin to drift. This would be annoying if not devastating, because over a period of about 700 years our summers, which we’ve come to expect in June in the northern hemisphere, would begin to occur in December.
- Who made leap days? By the third-century BCE, Egyptians followed a solar calendar that spanned 365 days with a leap year every four years. Julius Caesar would later adopt this calendar, inspired by the Egyptians. Caesar’s math of 365.25 days was close, but it wasn’t the exact 365.2422 days the solar year contains- in fact its roughly 11 minutes short. As a result, the Julian calendar would be short a day once every 128 years.
- When Pope Gregory introduced the Gregorian calendar in 1582, he likely didn’t know that it too was not perfect: the Gregorian calendar falls short once every 3,030 years.
- What happens if you are born on leap day? With odds of one-in-1,461, a leap day birthday is the rarest one can have. At least 5 million people across the world boast a leap day birthday nonetheless.
- What are the upcoming leap days? On the Gregorian calendar, leap years occur once every four years. They will be Feb 29 2028, 2032, and 2036.
By Olivia Munson for USA TODAY:
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