The main fragment of the Mechanism, found after two thousand years under water. A watercolor and ink drawing by DIonysia Xanthippos

The name "Antikythera" has nothing to do with "Antique." It means "anti-Kythera" or "opposite Kythera," and is the name of a tiny island in the Mediterranean that lies between the islands of Crete and Kythera, off whose coast it was found in 1900 in an ancient shipwreck by sponge-divers looking for giant clams. An inconspicuous heap of hopelessly corroded metal lying among a treasure trove of pots and piles of human bodies, one arm of which was brought to the surface, and turned out to be bronze -- the first of 96 naked young men in bronze from the 4th c BC -- the ugly lump went unnoticed even by officials at the Athens Museum, until 1958, when Yale's Derek de Solla Price began studying it. And kept at it, right up until his death.

Recently an 8-ton X-ray machine called "Bladerunner," designed by X-Tek Systems of Great Britain, took 3000 X-ray images of one fragment in an hour, later reassembled by a computer into a 3-D image. (See my article, "The Sphinx and the Robot," for a detailed account of how the ancient Naxos Sphinx was digitally scanned by a French-Italian team and then reassembled into a 3-D image that was then reproduced in marble by a computer-directed stone-cutting robot.)

A detail of a modern working model of the Antikythera Mechanism made by Dionisios Kriaris can be seen Here. On the outer circular dial are the 12 Greek months of the year, marked after the Babylonian calendar into 360 days - which is why a circle has 360 degrees. The inner dial, with the 366 days of the Egyptian calendar, shows the Greek Zodiac; across its top are Hydrokoon (Aquarius), Icthyas (Pisces), Krion (Aries) and Tauron (Taurus). Between the last two is a pointer with the bronze ball of the Sun, while below, on a revolving pin extending from the central Earth (?) is the Moon, one hemisphere of which is white, the other black, to show its changing phases from full moon to new moon.

The Metonic and Saros cycles on the Mechanism, and the Cosmos as a Geared Machine.

You can clearly see HERE the metonic and saros cycles on the back side of a very nice brass and plexiglas replica of the Mechanism by Massimo MOGI Vicentini that is on display in the Milan Planetarium.

On the back side of the Mechanism are two separate circular gears and dials, one for the Metonic cycle, the other for the saros cycle. Babylonian astronomers had discovered that one could reconcile the 360 days in the 12 months of a lunar year with the 365 days in a solar year only after 19 years, i.e. only after 235 lunar months. In other words, if you observe a full moon on April 13, there will not be another full moon in that same place on April 13 until nineteen years later. This cycle came to be known as the Metonic cycle, after the Greek astronomer Meton of Athens. It was a neat way to keep the lunar calendar and the solar calendar in synch.

Astonishingly, Derek de Solla Price had predicted those 235 divisions would be in there somewhere even though they were not visible until the recent 3-D X-ray scan revealed them on spiral fragment E. On another fragment Price found the number 223, which is the number of lunar months in the saros cycle, a way of predicting eclipses, also discovered by the Babylonians, who found that 18 years, 11 days and 8 hours after an eclipse a nearly identical eclipse would occur. Since eclipses were omens that could predict important future events, such as the outcomes of battles and the births and deaths of kings, for thousands of years astronomer-astrologers were courted by princes and emperors. In fact two of the pioneers and "stars" of modern astronomy, Tycho Brahe and Johannes Kepler, earned money and fame as court astrologers.

Working out the geometry of the Babylonian cycles as perfect circles, the Greeks built up a theory of the cosmos as a system of rotating circles and spheres. Since they still viewed the cosmos as an earth-centered ("Ptolemaic") system, to account for the apparent motions of the stars and planets around the earth, and each other, they had to introduce epicycles, or circles revolving on circles, just as smaller gears rotate on larger gears in the Antikythera Mechanism. As Alexander Jones, a professor of classics at the University of Toronto, said to John Seabrook, author of a New Yorker article on the Antikythera Mechanism, “The Greeks saw the Babylonian formulas in terms of geometry—they saw all these circles all spinning around each other in the sky. And of course this fits in perfectly with the concept of gearworks—the gears are making little orbits.”

But try to make such a machine with elliptical gears! Ironically, it was Kepler's obsession with proving and perfecting this divinely perfect mechanism of circular gears and orbits that forced him to break it. After a decade of trying to fit Tycho Brahe's observations, especially of the planet Mars, into circular orbits, he gave up and found they did fit into ellipses -- thereby discovering his famous law of elliptical planetary motion.

But circles or ellipses, it matters little. The astonishing thing about the Antikythera Mechanism is that it anticipates for two millennia the modern model of the Cosmos, from Galileo to Newton and beyond, of the world as a perfect Machine - a machine that runs on its own like clockwork, without any outside tinkering or adjustments, obeying only the laws of Celestial Mechanics.

Those are also the laws of Terrestrial Mechanics, governing the behavior of bodies on earth and beneath the sea, from cannonballs to sinking ships. But it is an illusion to think they govern the behavior of all sublunary bodies, such as spongers and hedge-funders, whose off-course actions and aberrancies, according to so-called "classical" economics, will be corrected by an "invisible hand." As Einstein insisted, "God does not play dice with the Universe."

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The two main front dials with English inscriptions can be seen in a transparent plexiglas model in an article by Michael Lahanas, "Gears by Archimedes and Others"
HERE

To see the many steps in Massimo MOGI Vicentini's reconstruction of the Mechanism, go to his fascinating illustrated web page "The Antikythera Celestial Machine: fragments of genius from a legendary science" HERE

Whle writing this article on the Antikythera Mechanism -- touted by many as "the world's first analog computer"-- I wondered: "What if Kepler had had the use of such a machine? Could he have cut off months, maybe years, from his laborious calculations of the positions and orbits of the planets?" In 1623, in response to Kepler's complaints about the tedium of his hand-calculations, his friend Wilhelm Schickard of Tübingen built for him the first mechanical calculator and he, rather than Pascal, became the real father of modern computers. Since Schickard's machine used techniques such as cogs and gears and rotating wheels first developed for clocks, he called it the "Calculating Clock." See my article in Celestia group, "Did Kepler use the world's first computer?" HERE

For the main sources of the facts about the Mechanism in my article, see:

John Seabrook, "Fragmentary Knowledge. Was the Antikythera Mechanism the World's First Computer?"
The New Yorker Magazine, May 14, 2007
www.newyorker.com/reporting/2007/05/.../070514fa_fact_seabrook

"Ancient machine opened the heavens. Their astronomical calculator was so sophisticated, it was unequaled for centuries."
By Thomas H. Maugh II, Los Angeles Times Staff Writer
LA Times, November 30, 2006
www.nature.com/nature/journal/v444/n7119/full/444534a.html
Posted by me on Ancient Worlds Dec 3, 2006

Derek De Solla Price's account of the discovery of the Antikythera Mechanism and his own work on it appeared in the June 1959 issue of Scientific American ("An Ancient Greek Computer," pp 60-67. Online in several sites; here's one: http://www.world-mysteries.com/sar_4.htm
See also, Jo Marchant, "In search of lost time," Nature (November 30, 2006), pp 534-538
www.nature.com/nature/journal/v444/n7119/full/444534a.html