Good day everyone, Julian here for DNews. Have you ever wondered why the calendar is

the way it is? What drove us in the western world to have a 365 day year? Turns out it’s

an interplay between astronomy, religion, and history.

The calendar we use right now is the Gregorian calendar, so named because it was implemented

by Pope Gregory the thirteenth in 1582. Why would the pope be interested in the calendar?

[[*RE-TRACKED on 12/18 - Cars have faces shoot*]]Well Easter was traditionally supposed to fall

on the Sunday after the first full moon after the spring equinox, March 21st, but it had

started slipping later and later behind the solar event. Gregory was worried they were

missing Christ’s rebirthday, so he commissioned italian scientist Aloysius Lilius to fix it

and make sure they were on Jesus’ good side. When they made the switch, the catholic world

jumped forward a full 10 days. And you thought daylight savings was bad. Many non-catholic

countries wouldn’t adopt the Gregorian calendar for hundreds of years still. Russia switched

after their October revolution in 1917, which under the new system, technically began in

November.

The reason the Gregorian Calendar is more accurate with our solar cycle is because it

changed how we approached leap years. It still has a leap year every 4 years, like the Julian

Calendar, except for years that are divisible by 100, except except for years that are divisible

by 400. So 2000 was a leap year, but 2100 will not be.

Why this wonky system for leap years? As it turns out, our revolution around the sun is

not a perfect 365 days, but 365 days, 5 hours, 48 minutes and 46 seconds. Before Julius Caesar

became emperor the calendar was all over the place, literally being manipulated by the

roman high priest for political reasons. Sometimes years were lengthened to keep allies in office,

sometimes they were shortened to kick rivals out quicker.

Julius Caesar put a stop to that by standardizing the Julian calendar. Introduced in 45 BCE,

or what to the romans was 709 as they counted years from the founding of the city of Rome.

His calendar had 365 days every year with an extra day every 4. It still made the average

year length 11 minutes and 14 seconds too long, but that wouldn’t be evident until

hundreds of years passed. To honor him for reforming the calendar, the roman senate changed

the name of Caesar's birth month to July. They’d honor him again a year later by murdering

him on the infamous ides of March

I always wondered, if Caesar could change the calendar willy nilly, why didn’t he

just get rid of March? Way to drop the ball, Caesar.

The reason we’re in the year 2015 though and not 2768 is because in 525 Christian Monk

Dionysius Exiguus determined that Jesus was born in the roman year 753, and started counting

over again from there. Because of him we get the terms BC for before Christ, and AD, which

does not stand for After Death but actually Anno Domini, which in Latin means “The Year

of Our Lord.” In the academic and scientific communities, to keep things neutral and welcoming

to people of all faiths, you’ll often see the terms BCE and CE for Before Common Era

and Common Era.

Of course the Gregorian Calendar is far from the only calendar in use around the world

today. Many calendars from cultures with less pronounced seasons actually rely on the cycles

of the moon instead of the Sun. But for predicting the change of seasons, equinoxes, solstices,

and when certain constellations will be visible, the Gregorian is the one we prefer for its

regularity. At least until 4909, when it’ll be a day ahead.

If you already blew it on your new years resolution, I’d say switch to the Julian calendar and

try again next week. But first check out Catie’s video on what you did wrong over here.

I’ve never lived by a different calendar but I’m sure a lot of you out there watching

do. What’s it like going by a system where the seasons aren’t the same dates each year?

Do you use the gregorian calendar too? Let us know in the comments, and I’ll see you

next time on DNews.