Where did Leap Year originate from and why?
It’s old. I forget the history and I can’t bother to look it up. We need a leap year because our year is supposed to last the exact same amount of time as one rotation around the Sun. However, it doesn’t line up perfectly. It’s actually closer to 365.25 years. So once every four years we add an extra day to keep it even. Otherwise the seasons would eventually get thrown off. It would take a while, but a day every four years adds up when you consider that our basic calender has been in effect for more than 2000 years. And since the year isn’t exactly 365.25 years, there’s another tweak. Whenever we start a new century (1800, 1900 etc) it’s not a leap year unless the year is also divisible by 400. So 2000 was a leap year, but 2100 won’t be.
