So I keep forgetting about the last Sunday of the month, and this month, Leap Year threw me off, so now it’s the first Sunday of the month coffee chat.
All day yesterday, all I heard was “You get an extra day.”
Leap year exists because the earth orbits the sun at 365.2421 days. Rather than program in a fourth of a day every year, we just add one year every four to even out the days and keep the seasons in the correct months and the days on schedule.
Many ancient cultures would just add whole months when the years and seasons got out of sync. The Romans first had a 10-month calendar with a winter period that would change every year. As things became unaligned, January and February months were added in, but the years were still off. It feel to the consuls (the rulers) of Rome to fix the situation, which of course they did to suit their own political agenda.
The Julian Calendar
By the time of Julius Caesar, something had to be done. He redid the entire Roman calendar, which is the one we follow to this day. When he was in Egypt, which, at that time, held the library of Alexander, a library that contained most of the world’s known knowledge at that time, Caesar saw how the Egyptians added ina an extra month every so often. Caesar, along with Sosigenes of Alexandria decided to make it easier with one day every four years. They picked February to add that day to since that was the month the Romans always tweaked to make up for “lost time.” In 46 BC, Caesar had to add in two extra months to balance out the calendar, so in 45 BC, the Julian Calendar was born with Leap Year or day added day every four years was born.
The Gregorian Calendar
However, since the earth’s rotation is .2421, this still makes the days skewed. So, by 1500 AD, enough time had passed that the calendar was off again. This was annoying to the Roman Catholic church since now Easter was off. Tradition holds that Easter is the first Sunday after the first full moon following the vernal equinox. By 1500 Easter was off by roughly ten days. Thus, Pope Gregory XIII modified the calendar once again, one which kept Leap Day but eliminated it on centurial years not divisible by 400 (1700, 1800, and 1900 were not leap years, but 2000 was). Thus, it’s not quite every four years a Leap Year is added. This Gregorian Calendar is the last change to the Western calendar as we know it today.
Do note that the calendar will have to be modified again, but only once every 3,030 years, so we won’t be affected by this.
Fun Fact: Those born on Leap Day are rare. There are only about five million people alive today born on a Leap Day with the chances of being born on Feb 29th at 1 in 1,461. They are called Leaplings, and while it may not be fun to skip your birthday, it would be fun to be in an elite group.
Back to my point: it wasn’t really an extra day. It’s not like I’m going to live an extra day. It was more just a day to live.