Blame it on Julius Caesar and Pope Gregory XIII. If it wasn’t for them, it might be the middle of summer right now.
Okay, that’s a fallacy. Actually, the Earth would still be in the same position relative to the sun and it would still be cold and/or wet and/or dreary outside. But it might be the middle of June!
Truly, without Leap Year and February 29 — that 366th day every four years — the calendar would be all over the place and, like the Australians, we could have winter in the middle of June, but without the sunshine, shrimp and Sheilas.
You see, the Earth’s rotation on its axis (by which we measure days) and its orbit around the sun (by which we measure years) are not exactly in sync. “What’s that?!” you exclaim. Well, a year is the time it takes the Earth to orbit the sun; but you knew that. The Earth’s orbit around the sun actually takes slightly more than 365 days — 365.24219 days to be exact. This is known as the “tropical” year.1
So, if it weren’t for Leap Year and Leap Day, the paper calendar would keep falling behind the solar calendar by a day every four years or so. In 720 years give or take, we’d have winter in June and summer in December, and, boy, would the Aussies be mad!
Even then, adding an extra day every four years isn’t perfect. Because Earth’s orbit around the sun is not exactly 365 1/4 days, if we kept adding leap days every four years without end, well, after a few thousand years, we’d wind up with winter in June. Therefore, there are only 97 leap years — not 100 — every 400 years.
So, for convenience sake, we skip Leap Year every 100 years, except we still leap in centennial years that are divisible by 400. If you’re still keeping up, that means there was no Leap Day in 1900, but we did have one in 2000, and we will skip Leap Day again in 2100.
As a result, the average number of days in a Gregorian year is 365.2425. Trust me, I looked it up. Still not perfect, but I guess we don’t have to worry about that extraneous 0.0003 of a day (26 seconds — you do the math) during our lifetimes. It won’t need correction for about 3,333 years.
The Druids, who — as the legend goes — built Stonehenge, were probably the first ones to discover the tropical year phenomenon, even though they did not live in Hawaii. But since their calendar was strictly solar, it didn’t matter to them. They didn’t care about months or days of the week, so they didn’t write it down. They’d just wake up in the morning every four years or so, turn to one another around the fire and say, “Did those last four years seem a little longer to you?”
They kept on sowing and reaping according to the solstices and equinoxes. Problem is, they wound up working too many weekends and productivity lagged on Wednesdays. They disappeared; probably caught napping when the Normans invaded … or something.2
In fact, Leap Year was introduced by Julius Caesar, who reformed the Roman calendar in 46 B.C. at the urging of the Greek Sosigenes, for whom nothing is named. At the same time, Caesar, for whom the resulting Julian calendar3 and the month of July were named,4 added 90 days to the year 46 B.C. to catch up with the seasons. There is no word, however, on whether annual salaries were adjusted accordingly. (Caesar also added 10 days to the year in general. The previous Roman year was only 355 days.)
Around 10 B.C., it was found that the priests in charge of computing the calendar had been adding leap years every three years instead of the four decreed by Caesar. As a result of this error, no more leap years were added until 8 A.D. The first leap years were therefore 45 B.C., 42 B.C., 39 B.C., 36 B.C., 33 B.C., 30 B.C., 27 B.C., 24 B.C., 21 B.C., 18 B.C., 15 B.C., 12 B.C., 9 B.C., 8 A.D., 12 A.D., and every fourth year thereafter, until the Gregorian calendar was introduced (resulting in skipping — also known as non-Leaping — three out of every four centuries).
The Gregorian calendar, which is named for Pope Gregory XIII, who issued the official decree, supplanted the Julian calendar in 1582. The difference is the centennial omission of Leap Day except … well, you know. As innocuous as it seems, the move was not immediately welcomed.
You see, in 1582 — due to the 100-year problem — there was a 10-day difference between the actual time of year and the traditional time of year on which calendrical events occurred, e.g., solstices and equinoxes. It apparently was driving people crazy.
To account for this discrepancy, Pope Gregory decreed that October 4, 1582 would be followed by October 15, 1582. Like the Centurions who protested the lack of a salary adjustment, Pope Gregory’s edict was met with protests by many of the common folk, who believed it to be an attempt by landlords to cheat them out of 10 days’ rent, not to mention the poor kids who were cheated out of their birthdays and their Pope Gregory action figures.
The Catholic countries of France, Spain, Portugal and Italy readily complied. Various Catholic German countries (Germany was not yet unified), Belgium, the Netherlands and Switzerland followed suit within a year or two, and Hungary followed in 1587.
The Protestant German countries adopted the Gregorian reform in 1700. By this time, the calendar trailed the seasons by 11 days. England (and the American colonies) finally followed suit in 1752, and Wednesday, September 2, 1752 was immediately followed by Thursday, September 14, 1752. This traumatic change resulted in widespread riots and the populace demanding, “Give us the 11 days back!” and “No taxation without representation.” No, wait, that did not happen until the Stamp Act protests of 1765. Sorry.
The 11-day time warp also caused some consternation with George Washington’s birthday (I kid you not). You see, old George was born in 1732 on — which was at the time — February 11. After the 1752 calendar adjustment in the American colonies, Washington marked his birthday on February 22, as we now know it, although some of his Virginia neighbors adhered to the 11th.5
So, in honor of Leap Year, Leap Day and George Washington, I think that during this 2,000th anniversary year of the reincarnation of Leap Day under the reign of Augustus Caesar, for whom the month of August was named, we should celebrate the birthday of the Father of Our Country twice. Take an extra Monday off! Maybe in August, when it’s summer (winter in Australia) and there are no regularly scheduled holidays.
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1 Many of the facts in this article are courtesy of “Eric Weisstein’s World of Astronomy,” http://scienceworld.wolfram.com/astronomy. I made up the rest.
2 In case you’re wondering, this is the part I made up.
3 Not to be confused with a julienne colander, which is used to rinse and/or drain thinly sliced vegetables.
4 The Caesarian section — the legendary manner in which Caesar was born (although most likely not) — also is named for him (or not). The Caesar salad definitely is not, but that’s another show, as Alton Brown would say.
5 James Thomas Flexner, George Washington: The Forge of Experience (1732-1775) at 12 (Little, Brown & Co. 1965).
