You may think that Christmas season is finished. Not so fast. January 7 is the Christmas day by the Eastern Orthodox Church calendar, so this is the high time for Christmas celebrations in Eastern Europe — Russia and Ukraine, in particular. Ever wondered why? Read on.
The story begins with the Solar System. Most people know that Earth year is approximately 365 days. By the age of 4 or 8 years, most people learn that the year is approximately 1/4 day longer than 365 years. The accrued extra day is added as Februrary 29th every 4 years. The “long” year is called leap year. Almost every year that can be divided by 4 is a leap year. The calendar accounting for the extra day every 4 years was introduced by Julius Caesar in 46 BC and is, therefore, called Julian.
By the age of 100 or 200, most people learn that the year is approximately 0.008 days shorter than 365 and 1/4. The accrued missing day is taken away by skipping 3 leap years every 400 years. Each year that can be divided by 100 is not a leap year unless it can also be divided by 400. Years 1900 and1800 are not leap years. Year 2000 is a leap year. Of course, most people do not live to the age of 100 or 200 and never learn that most centennial years are not leap. The calendar accounting for the missing leap years was introduced by Pope Gregory XIII in 1582 and is, therefore, called Gregorian. They do have to know a thing or two about science, those Popes.
The “approximately” does not end there. Of course, there are more decimal places in the length of the year calling for more adjustments, but most of the people do not live long enough to notice.
By 1582, the 0.008 days every year have accrued 11 days. Gregorian calendar corrected Julian calendar by skipping 11 days in October 1582:
Atheists are not the only people who think that Pope is no authority to them. Protestants and Americans have not adopted Gregorian calendar until September 1752. By the time they decided to switch, they had to skip 12 days:
(as if there were United States in 1752). When I learned UNIX commands in college, I was surprised to find out that UNIX “cal 1752” command produces this:
You may be surprised to learn that Eastern Orthodox Church is still using Julian calendar for its holidays! Now, the difference is 13 days! So, Orthodox Christmas is on December 25, except that December 25 “old style” falls on January 7 “new style”. For the same reason, the anniversary of The Great October Socialist Revolution, a major holiday in the Soviet Union, was celebrated on November 7. When the revolution happened, it was October 25th, but when the Soviet Union converted to Gregorian calendar in 1929, the date moved to November 7th. Julian calendar was still in use until 1930 in the Soviet Union. In year 2100, another leap year will be skipped adding to the schism separating Eastern Orthodox Christians from the rest of the world. Starting from year 2101, Orthodox Christmas will move forward another day — to January 8th. I wonder, how well this change will be received.
In case you wonder, yes, they celebrate the New Year “old style” on January 14 in Eastern Europe. It’s called “the old new year“.