The problem:

While a year seems like a neat 365 days, Earth actually takes about 365.25 days to circle the sun. That extra quarter-day adds up over time, messing with the seasons and throwing off important dates like equinoxes.

The solution(s):

Enter Julius Caesar in 45 BC, the OG leap day enthusiast (or maybe just the guy who took the blame). His Julian calendar included a leap day every four years, which worked pretty well for centuries. However, it wasn’t perfect. The math was slightly off, leading to a small drift over time.

Fast forward to 1582, when Pope Gregory XIII introduced the Gregorian calendar we use today. This new system tweaked the leap year rules, adding some extra complexity but ensuring better long-term accuracy. So, the next time you encounter a leap year on your calendar, remember: it’s not just a random quirk, it’s a testament to human ingenuity and the never-ending quest for calendrical harmony!

The details:

via MathIsFun:

How to know if it is a Leap Year:

yes Leap Years are any year that can be exactly divided by 4 (such as 2020, 2024, 2028, etc)
not except if it can be exactly divided by 100, then it isn’t (such as 2100, 2200, etc)
yes except if it can be exactly divided by 400, then it is (such as 2000, 2400)

This extra day popping up every four years might seem random, but it all boils down to keeping our calendars in sync with the Earth’s funky orbit.

 

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