Well, I'll be snookered!
Remember when I made posts about how J.S. Bach's birthday was incorrectly recorded?
Well, let's review the facts, this time using some convenient terminology. (Truly, language helps us clarify an absolute host of obscure ideas.)
Basically, our Earth year is not an exact number of days. Little kids are taught that a year is 365 days long. But most of us learn later, that it's about 365-and-a-quarter days. We let the quarters pile up, and every 4 years or so, we add in Feb 29. (You realize that February usually only has 28 days.)
Unfortunately, a year is a tiny bit less than 365 and a quarter days. So, the Feb 29th Leap Day is advancing the calendar too fast. Over several centuries, the Equinox landed almost a month too late.
By the time the papal astronomers got up the guts to make a move on this problem, it was the papacy of one Pope Gregory (Pope Gregory XIII, 1572–1585), a millennium and a half after Julius Ceasar. Luckily for everybody, the shortfall is, I believe, in the order of a few minutes. But over so many years, these minutes certainly added up.
I certain parts of Germany in the 1600s, people hated the Pope with a passion. (Remember: Martin Luther was from Saxony, the very region in which Bach was born.) They stuck with the outdated Julian Calendar. The dates recorded for births in Thuringia, for instance, were according to the Julian Calendar. Some time later, everybody realized that calendars had little to do with religion, and using the new Gregorian Calendar had huge advantages. The Gregorian dates were called New Style Dates, and the older dates were called Old Style Dates. Bach's Old Style Birthday was March 21.
I celebrate his birthday on that date, because it's the Equinox, which is cool. Also, if Bach were somehow raised from the dead, he would give his DOB as March 21.
Well, guess who else had an axe to grind about the calendar? The English! At the time of Isaac Newton, England, too, used the Old Style Julian dates. Isaac's birthday had been celebrated for a Century or two as Christmas Day! But then, British astronomers saw the light, and Isaac's birthday was revised to be January 4th.
You might not realize that the divergence between Old Style and New Style dates grows steadily, as those minutes add up. In 1643/1642, Newton's birth year, the difference was just about 10 days; in Bach's it was a little greater. Today, if anyone aspires to use the Old Style Calendar, the divergence would be crazy. (I should be able to tell you exactly how much, but I'm too unmotivated to figure out out; after all, I'm retired. Or just plain tired.)
Well, Happy Wednesday, as the man said!
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