The Calendar Read online

  THE CALENDAR

  DAVID EWING DUNCAN

  The 3000-year struggle to align the clock and the heavens--and what happened to the missing ten days

  To Sander, Danielle and Alexander and thanks to Stephen

  Copyright © David Ewing Duncan 1998.

  The right of David Ewing Duncan to be identified as the author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.

  A catalogue record for this book is available from the British Library.

  ISBN 1-85702-979-8

  David Ewing Duncan is a writer and traveller. The author of four previous books, this is his first UK publication. He is also a documentary film producer, and special correspondent and producer for ABC News.

  Calendar Index

  Length of the (tropical) year in 2000 AD: 365 days, 5 hours, 48 minutes, 45 seconds

  Time that the year has slowed since AD 1: 10 seconds

  Average decrease in the year due to a gradual slowing of the earth’s rotation: 1/2 second per century

  Lunar Month: 29 days, 12 hours, 44 minutes, 2.9 seconds

  The earliest known date: 4236 BC, the founding of the Egyptian calendar

  Ancient Egyptian year: 365 1/4 days

  Early Chinese year: 354 days (lunar year) with days added at intervals to keep the Chinese lunar calendar aligned with the seasons

  Early Greek year: 354 days, with days added

  Jewish year: 354 days, with days added

  Early Roman year: 304 days, amended in 700 BC to 355 days

  The year according to Julius Caesar (the Julian calendar): 365 1/4 days

  Date Caesar changed Roman year to Julian calendar: 1 January 46 BC

  Amount of time the old Roman calendar was misaligned with the solar year as designated by Caesar: 80 days

  Total length of 45 BC, known as the ‘Year of Confusion,’ after adding 80 days: 445 days

  The year as amended by Pope Gregory XIII (the Gregorian calendar): 365 days, 5 hours, 48 minutes, 20 seconds

  Date Pope Gregory reformed the calendar: 1582

  Length of time the Julian calendar overestimates the solar year per year, as determined by Pope Gregory: 11 minutes, 14 seconds

  Number of days Pope Gregory removed to correct the calendar’s drift: 10

  Dates Gregory eliminated by papal bull to realign his calendar with the solar year: 5-14 October 1582

  Dates most Catholic countries accepted the Gregorian calendar: 1582-1584

  Date Protestant Germany accepted the Gregorian calendar: partial acceptance in 1700, full acceptance in 1775

  Date Great Britain (and the American colonies) accepted the Gregorian calendar: 1752

  Length of time eliminated by the British Parliament to realign the old calendar (Julian) with the Gregorian calendar: 11 days

  Dates Parliament eliminated: 3-13 September 1752

  Date Japan accepted the Gregorian calendar:

  1873 Date Russia accepted the Gregorian calendar: 1917 (and again in 1940)

  Date China accepted the Gregorian calendar: 1949

  Date the Eastern Orthodox Church last voted to reject the Gregorian calendar and retain the Julian calendar: 1971

  Length of time the Gregorian calendar is off from the true solar year: 25.96768 seconds per year

  Length of time the Gregorian calendar has become misaligned over the 414 years since Gregory’s reform in 1582: 2 hours, 59 minutes, 12 seconds

  Year in which the Gregorian calendar will be one day ahead of the true solar year: AD 4909

  Year that Atomic Time replaced Earth Time as the world’s official time standard: 1972

  The year as measured in oscillations of atomic caesium: 290,091,200,500,000,000

  The Year 2000 Will Be

  1997 according to Christ’s actual birth circa 4 BC

  2753 according to the old Roman calendar

  2749 according to the ancient Babylonian calendar

  6236 according to the first Egyptian calendar

  5760 according to the Jewish calendar

  1420 according to the Moslem calendar

  1378 according to the Persian calendar

  1716 according to the Coptic calendar

  2544 according to the Buddhist calendar

  5119 in the current Maya great cycle

  208 according to the calendar of the French Revolution

  The year of the DRAGON according to the Chinese calendar

  Time is the greatest innovator--Francis Bacon, 1625

  Which Year?

  When I refer to the ‘calendar year’, or the ‘solar year’, I mean the tropical year unless otherwise indicated. The simple definition of the tropical year is the year according to the length of time between two successive vernal equinoxes, which occur at the exact moment when the centre of the sun appears to cross the equator as it moves from south to north. Because this measurement fluctuates from year to year, the tropical year is usually calculated as a mean of several years. The tropical year is slightly different from the sidereal year, which measures the length of time it takes for the earth to orbit the sun, returning to a starting point according to a fixed point such as a star.

  D.E.D.

  Prelude: A Net Cast Over Time

  The . . . silent, never-resting thing called time, rolling, rushing on, swift, silent, like an all-embracing ocean tide . . . this is forever very literally a miracle; a thing to strike us dumb.

  Thomas Carlyle, 1840

  Not long ago I met a well-known surgeon dying in a hospital in Richmond, Virginia. He was a distressingly emaciated figure, his face a mask of skin over his skull, his hands a pale shade of purple from weeks of intravenous needles. Yet his voice remained deep and powerful, his eyes lively. When a friend asked how long he was going to be in the hospital this time, the surgeon said he didn’t know, that time was becoming irrelevant to him. ‘It’s ironic,’ he said, smiling weakly. ‘I lived by the calendar for sixty years. Beepers, schedules--these things ruled my life. Now I have no idea what day it is, and this doesn’t bother me. It’s as if I am floating,’ he said, leaning back on crisp hospital sheets and almost whispering the words.

  Our obsession with measuring time is itself timeless. After self-awareness, it may be our most distinctive trait as a species, since undoubtedly one of the first things we became self-aware about was our own mortality--the fact that we live and die in a set period of time.

  Yet even in an age of measuring femtoseconds* and star clusters 11 billion light-years away, time defies true objective measurement. It can seem to go slow and even stall out at certain moments only to brashly and breathlessly rush forward at others. Time can be wasted, kept, saved, spent, killed, lost and longed for. To the Nuer herdsmen of southern Sudan, time is tot and mai, wet and dry, depending on the season. For Hesiod, the ancient Greek poet, time is harvesting cereals in the month when the cuckoo sings, and a low sex drive for men during the late summer, when ‘goats are at their fattest and the wine tastes best.’

  *A femtosecond is one quadrillionth of a second.

  Consider the geometry of how we measure time. It can be divided into circle time and square time: clock time and calendar time. Clock time chases itself like Ouroboros, the hands or flashing numbers returning to the place where they started in a progression that has no beginning or end. It will continue in its cycle whether or not people are around to watch the hands and glowing numbers. In contrast, calendar time is made up of small boxes that contain everything that happens in a day, but no more. And when that day is over, you cannot return to that box again. Calendar time has a past, present and future, ultimately ending in death when the little boxes run out.

  Still, in modern times we take the mechanism of the calendar f
or granted, as we do breathing and the force of gravity. Passing through years, months, weeks, hours, minutes and seconds we seldom think about where these things came from, or why we have chosen to divide time one way and not another.

  It has not always been so. For thousands of years the effort to measure time and to create a workable calendar was one of the great struggles of humanity, a conundrum for astronomers, mathematicians, priests, kings and anyone else who needed to count the days until the next harvest, to calculate when taxes were due, or to figure out the exact moment a sacrifice should be made to appease an angry god. A case can be made that science itself was first sparked by a human compulsion to comprehend the passing of time, to wrestle down the forward motion of life and impose on it some sense of order.

  The effort to organize and control time continues unabated today. It is one of humankind’s major collective efforts as we hedge our future and try’ to comprehend the past. In the stock market an investor sells a microchip stock short or long based on a reading of the company’s history. In river valleys we build dams and levees to prepare for 10, 50 and 100-year floods. We celebrate Easter, Passover and Ramadan on prearranged dates just as our ancestors did centuries ago, and we expect our children will for centuries to come.

  We are a people of the calendar. Forward-and backward-looking, we are uncomfortable with the present in a way that our ancestors who tilled fields and lived and died according to the great cycles of nature would never have comprehended.

  What are you doing at one o’clock tomorrow? Can you book me on the 2:06 flight to Memphis next Thursday? When will the inventory ship? Ten-nine-eight-seven-six-five-four-three-two-one-zero: blastoff!

  Holding the surgeon’s wasted hands in that Richmond hospital,

  I thought about my schedule for the rest of the day. Meetings, engagements, phone calls to make, a plane to catch to fly back home. I needed to pick up a small present for my eight-year-old, and I had to remember to put petrol in my hire car before I turned it in at the airport. In a way I envied the doctor because he could let go and I could not. This is our blessing and our curse: to count the days and weeks and years, to calculate the movements of the sun, moon and stars, and to capture them all in a grid of small squares that spread out like a net cast over time: thousands of little squares for each lifetime. How this net was woven over the millennia, and why, is the subject of this book.

  Time Line: A Chronology of Events

  1 A Lone Genius Proclaims The Truth About Time

  The calendar is intolerable to all wisdom, the horror of all astronomy, and a laughing-stock from a mathematician’s point of view.

  Roger Bacon, 1267

  Seven centuries ago a sickly English friar dispatched a strident missive to Rome. Addressed to Pope Clement IV, it was an urgent appeal to set right time itself. Calculating that the calendar year was some 11 minutes longer than the actual solar year, Roger Bacon informed the supreme pontiff that this amounted to an error of an entire day every 125 years, a surplus of time that over the centuries had accumulated by Bacon’s era to nine days*. Left unchecked, this drift would eventually shift March to the dead of winter and August to the spring. More horrific in this pious age was Bacon’s insistence that Christians were celebrating Easter and every other holy day on the wrong dates, a charge so outrageous in 1267 that Bacon risked being branded a heretic for challenging the veracity of the Catholic Church.

  *In this same treatise Bacon elsewhere uses the figure once in every 130 years. The actual error is closer to once every 128 years.

  Roger Bacon did not care. One of medieval Europe’s most original and curmudgeonly thinkers, he seemed to relish his role as a rebel--first as a master at the University of Paris in the 1240s and then as a priest after he joined the Franciscan order sometime during the 1250s, when he was in his forties. Insatiably curious and always willing to challenge orthodoxy, Bacon devoted his life to pondering what causes a rainbow, diagramming the anatomy of the human eye, and devising a secret formula for gunpowder. Two centuries before Leonardo da Vinci he predicted the invention of the telescope, eyeglasses, airplanes, high-speed engines, self-propelled ships and motors of enormous power. He drew these conclusions based on the then-radical notion that science offered objective truths regardless of dogma or what was written down in a book.

  Bacon’s contemporaries were impressed by his intellect but frightened of his ideas. His own monastic brothers at Oxford and Paris may have held him under house arrest. Even worse, they banned him for long periods from writing and teaching, keeping him busy with the mundane chores of the monastery--tending the garden, reciting prayers, scrubbing the floors. Occasionally they punished him by withholding food.

  This might have been the end of Roger Bacon’s story if not for a sudden interest in his ideas by a man named Guy Le Gros Foulques. In 1265 this former lawyer and advisor to King Louis IX of France became aware of Bacon and contacted him, asking the friar to send him a compendium of his thoughts. Like Bacon, Foulques had joined the priesthood later in life, in 1256, the year his wife died. He had then advanced with breathtaking speed from priest to bishop, archbishop and cardinal, his position when he approached Bacon. How Foulques heard about the long-cloistered friar is unknown, nor is it clear why this important cardinal was interested in Bacon’s ideas, nor if he agreed with them.

  Whatever his reasons, Foulques’s interest was a dramatic turn of events for Roger Bacon. The long-suffering friar must have felt as if he were finally being allowed to bring fire back to the cave. And if this were not enough, just a few months later Guy Le Gros Foulques was elected supreme pontiff of the Catholic Church, taking the name of Clement IV. This led to a second notice sent to Bacon: a papal mandate delivered in June 1266 to forward the friar’s work as soon as possible to St Peter’s in Rome.

  Bacon was elated but embarrassed, for after years of persecution by his own religious order, including at times a prohibition on writing, he had nothing complete enough to send to Rome. ‘My superiors and my brothers,’ a frustrated Bacon wrote to the pope, ‘disciplining me with hunger, kept me under close guard and would not permit anyone to come to me, fearing that my writings would be divulged to others than . . . themselves.’

  Free at last to pursue his ideas, Roger Bacon promised to prepare a manuscript and send it as quickly as possible. For nearly two years he worked feverishly, finally dispatching an epic treatise to Rome in 1267 called Opus Maius (Major Work). In this book and two others, hand-carried by a faithful servant named John along the sometimes treacherous medieval highway across Europe, Bacon expounds on topics ranging from a study of languages and the geometry of prisms to the geography of the Holy Land.

  His diatribe describing the flaws in the calendar falls in a long and rambling chapter on mathematics, in a section where he advocates using the objectivity of numbers and science to expose mistakes. He opens with an announcement that he is bringing up a matter ‘without which great peril and confusion cannot be avoided’, an error conceived out of ‘ignorance and negligence . . . [that is] contemptible in the sight of God and of holy men . . . The matter I have in mind,’ he says, ‘is the correction of the calendar.’

  Bacon traces flaws in the calendar back to its originator, Julius Caesar, who launched the calendar used by Bacon--and by us today with some modifications--on 1 January 45 BC. ‘Julius Caesar, instructed in astronomy, completed the order of the calendar as far as he could in his time,’ writes Bacon:

  But Julius did not arrive at the true length of the year, which he assumes to be in our calendar 365 days and one fourth of a day . . . But it is clearly shown . . . that the length of the solar year is not so great, nay, less. This deficiency is estimated by scientists to be about the one hundred and thirtieth part of one day. Hence at length in 130 years there is one day in excess. If this were taken away the calendar would be correct as far as this fault is concerned. Therefore, since all things that are in the calendar are based on the length of the solar year, they of necessity must
be untrustworthy, since they have a wrong basis.

  Bacon also condemns a second calendric mistake that comes out of the first. ‘There is another greater error,’ writes Bacon, ‘regarding the determination of the equinoxes and solstices. For . . . the equinoxes and solstices are placed on fixed day . . . But astronomers are certain that they are not fixed, nay, they ascend in the calendar, as is proved without doubt by tables and instruments.’

  This second point was critical, Bacon notes, because the spring equinox--astronomically the point between winter and summer at which the sun strikes the equator--is the date used by Christians to determine Easter. According to Church rules, Easter is celebrated on the first Sunday after the first full moon after the spring equinox.* In Bacon’s day the equinox was permanently fixed on 21 March by order of the Church, as established by an important Christian council held at Nicaea in Turkey in AD 325. But since 325, as Bacon notes, the equinox had been ‘ascending in the calendar . . . and likewise the solstices and the other equinox’ by 1/130 of a day each year, or just over 11 minutes. He set the true date of the equinox for the year he was writing, 1267, on ‘the third day before the Ides of March’, or 12 March--a nine-day difference. ‘This fact cannot only the astronomer certify,’ says Bacon, ‘but any layman with the eye can perceive it by the falling of the solar ray now higher, now lower, on the wall or other object, as anyone can note.’

  *The actual calculation of Easter is considerably more complicated than this, but this simplification will suffice for now.

  He calculates that by 1361 the calendar would drop back another whole day, throwing the entire progression of dates and sacred days further into disarray. The friar concludes with an appeal to Clement to embrace the ‘truth’ offered by science, and to fix the mistake:

  Therefore Your Reverence has the power to command it, and you will find men who will apply excellent remedies in this particular, and not only in the aforesaid defects, but in those of the whole calendar. ... If then this glorious work should be performed in your Holiness’ time, one of the greatest, best, and finest things ever attempted in the Church of God would be consummated.