How Old Can This Strange Machine Really Be?

Is the Baffling Antikythera Computer Even Older than We Realized?

A few days before Easter Sunday in 1900, two small ships of Greek sponge divers, seeking shelter from a storm, an­chored just off of the small barren island of Antikythera, in the Aegean Sea.

After the squall the ship’s divers discovered the remains of a 164-foot long ancient ship filled with bronze and marble statues, coins, gold jewelry, pottery, and other miscellaneous pieces. Among the finds was a small lump of corroded bronze and rotted wood. It was sent to the National Museum of Greece in Athens.

Soon after, as a consequence of the wood’s drying and shrinking the lump split open in several places. On May 17, 1901, archaeologist Valerios Stais noticed metallic gears protruding from the wood. Further inspection revealed a se­ries of gear wheels like a modern clock. Inscriptions within, however, indicated something to do with astronomical cycles.

In the years following, several researchers attempted to unravel the mystery of the strange geared device, but reached no definite conclusions. Finally, in 1951, the ancient machine came to the attention of Dr. Derek de Solla Price of Cambridge University and the Institute of Advanced Studies at Princeton. Beginning in 1958, working with a select group of specialists over a fourteen-year period and using advanced techniques such as gamma-radiography (a form of X-ray investigation), Dr. Price successfully reconstructed the machine’s appearance and use.

The original mechanism was enclosed in a rectangular wooden box with metal plate doors hinged to the front and back, the box being about the size, as Price described it, of a “thick folio encyclopedia volume.” Originally it measured 13 inches high, 6.75 inches wide and just 3.5 inches thick. Yet it contained more than two dozen intermeshing gear wheels. Nothing of a mechanical nature this compact or intricately made appeared until the advent of eighteenth cen­tury European clocks.

All the metal moving parts inside the machine were cut from a single sheet of special low tin, non-leaded bronze about one-sixteenth inch in thickness. Each of the gear wheels, now estimated to be about 31 in number, had teeth of the same size and 60-degree angle. Within the mechanism, the gear wheels were fixed to a bronze plate at the center of the box. Input was provided by an axle-shaft that passed through the side of the box and turned a crown wheel. This set in motion a large four-spoke driving wheel connected to several sets of gears with turntable-shafts that moved a number of pointers at various speeds around dials located on the front and back of the box.

There is evidence the machine was repaired at least twice—one of the drive-wheel spokes shows signs of having been mended, and a broken tooth on a small wheel was replaced. The machine was thus used and received wear.

An unaccounted-for space exists between some of the gearing, and there is good evidence that this space held a gearing system, now missing, which served to exhibit the rotations of all the planets on the front dial as well. In his 1974 book Gears of the Greeks, Price concluded that the mechanism was originally meant to show the motions of the Moon, the Sun, all the then known planets, the rising of the major stars, plus major solar and lunar eclipses, all against the backdrop of the celestial Zodiac.

As Price noted, the arrangement of the existing wheels shows that the gears could be moved forward and back­ward with ease at any speed. The device was thus not a clock but more like a calculator that could show the positions of the heavens—past, present and future—for reference, for study or for prediction.

When we look at the sum total of evidence from the internal gearing, the dials and inscriptions, it is clear that the purpose of the Antikythera machine was to mechanically calculate short-range and long-range astronomical cycles. In its capacity to do so, the small computer stands out as a contradiction to all previous concepts of ancient mechan­ics. Dr. Price, speaking in Washington D.C. in 1959, said: “Finding a thing like this is like finding a jet plane in the tomb of Tutankhamen. Nothing like this instrument is preserved elsewhere.”

So where did it come from?

Some historical scholars would equate the machine with the mechanical planetariums constructed by the Greek Sicilian Archimedes in about 250 B.C.E., whose work was later revived by an avid student, Posidonius of Rhodes, and still later by Geminus of Rhodes. But there are serious problems with ascribing to them the invention of the Antiky­thera device.

First, the descriptions of the orreries of Archimedes and Posidonius indicate that they were large and elaborate or­nate works of art showing the orbs of heaven in three dimensional form. The Antikythera device in contrast was com­pact, portable, completely devoid of ornamentation, a truly scientific instrument that exhibited the astronomical cy­cles in flat, circular projections marked off in scaled, graduated degrees, a technique employed nowhere else in the classical world, and not fully comprehended as a technological possibility until the late medieval period.

Second, there is the very real anomaly of the sophistication of the Antikythera gearing, in particular its differen­tial turntable. This feature was in reality several steps beyond the mechanical abilities of Archimedes or Posidonius. In fact, as Price himself admitted: “In my experience it is difficult even today to explain the theory of this gear work to the bulk of people in a modern audience familiar with a host of mechanical and electrical devices.”

In European civilization, differential gearing did not appear until 1575, used in the clock of Eberhart Baldewin of Kassel, Germany and this after over five centuries of continuous experimentation by early mechanists. No such background of development existed in the known Greek world, yet the Antikythera device, over two millennia old, exhibits a sophistication that even outshines the Renaissance clock.

Compounding the mystery further, there is reason to believe that the gearing of the Antikythera machine is older than what was originally thought.

When the bronze of the gear work was subjected to metallurgical and spectrographic analysis by Professor Earle R. Caley of Ohio State University, it was discovered to contain 4.1 percent tin, alloyed with the main component, cop­per, with a marked absence of lead. What is curious about this finding is that all late Greek and Roman bronzes, espe­cially those of the first century B.C.E., contained large amounts of lead, in many cases larger than the tin content.

Non-leaded bronzes, however, were a feature characteristic of much earlier periods by several centuries. On a piece of one of the graduated dials that was used to correct the Greek calendar of 365 days with a true solar year of 365.25 days, Price found a clear marking that he believes points back to the date when the correlation between the two calendars was first made. The date he calculated occurred in 586 B.C.E.—in the midst of the time when non-leaded bronzes were being utilized. Here is one indication that the calculator had been in use for at least five centu­ries before it was lost.

More than this, the outer box could be one age, while the gearing may in fact be even older. The internal machin­ery could have actually been built long before the machine’s present outer box, with its dials and inscriptions. The Greeks may have only re-discovered the original device, and had nothing to do with inventing the machinery. They simply remodeled and updated the outer dials and inscriptions to suit their needs and studies. The Greeks knew enough of how to interpret the pointers, without really understanding the machinery itself.

There is, too, the evidence of wear and tear on the gearing, with repairs having been made, indicating that it had been in use for considerable periods of time before the latest casing box was added.

The elements of Egyptian calendrical principles and Babylonian sixty-degree angling in the gear works point back to these earlier civilizations as the source. But once again, the evidence cannot be found of a background develop­ment for the machine’s invention in either location.

It is more likely that the device had its true origins ages long before, and in a land far removed, now unknown. Passed on from culture to culture, each studying its mechanical form and adding their own marks, the Antikythera device still harks to an original homeland that once boasted a lost machine age, one that in many ways was compara­ble to what modern civilization possesses today.

In 1993, Australian computer scientist Allan George Bromley of the University of Sydney, in cooperation with a Sydney-based clockmaker named Frank Percival, began improving on Dr. Price’s original suggested design of the An­tikythera gear work by first building a working reconstruction. This was further enhanced based on more accurate in­ternal images of the mechanism remains done in 1997 in collaboration with Michael Wright, Curator of Mechanical Engineering at Imperial College in London. They used a technique called linear X-ray tomography which allows the generation of sectional, three-dimensional radiographic imaging.

One aspect that Bromley and Percival focused on was the making of the gear wheels themselves. They noted how remarkably precise the gears had been cut and mounted, allowing all the wheels to turn without slippage or getting stuck when moved either forward or backward. This is due to the nearly absolute perfection of the 60 degree angles of all the gear teeth, which allows for a gap tolerance of less than five-hundredths of an inch. The two experts failed more than once in trying to cut identical bronzes using today’s best cutting tools with the same level of perfection ex­hibited in the ancient computer gears.

Even more remarkable than the overall perfection of the gears is the one-minute imperfection. It now appears that two connected gear wheels were deliberately misaligned very minutely, with a small pin inserted into one of the gears so that it could be moved slightly out of its place to simulate the irregular elliptical orbit of the Moon around the Earth, known today as the First Lunar Anomaly. As British astrophysicist professor Michael Edmunds observed af­ter he discovered this almost microscopic variation: “When you see that, you think, ‘that’s clever—that’s brilliant technical design.”

One unofficial explanation has been voiced by more than one expert that the Antikythera gears may have been cut with some form of laser. In a recent intensive microscopic study of the calculator’s metal surfaces, additional letter­ing was discovered, and astonishingly some of the letters measured only eight-hundredths of an inch in size—far too small to have been etched with any type of ordinary metal tool. The only way possible would have been using a tiny concentrated beam of laser light.

Wright has continued in his studies and has proposed an improved design which modeled the motions of not only the Sun and Moon, but also of both the Inferior and Superior Planets—from Mercury through Saturn. He also found evidence that the Antikythera machine showed the solar and lunar movements to be in accordance with the theories of Hipparchus, and the planetary oscillations occurred in harmony with the epicycles of Appollonius. In the mean­time, from his X-ray work Wright was able to increase the original machine’s gear count from 27 to 31.

Despite these new findings, however, Wright could no longer reconcile all of the gears into a single coherent mechanism, leading him to believe that the device had been altered or modified over a long period of time, with some features removed and others added. This goes to confirm the notion that the Antikythera computer is far older than suspected, and that it may have passed through the hands of several ancient cultures who were the source of its de­sign changes.

In 2005, it was announced from Athens that new pieces of the Antikythera device had been found, suggesting the mechanism had possessed a total of 37 gears, filling the gaps in its internal workings and their inter-meshing.

Based on these updated findings, research done by other independent investigators has made several remarkable and curious discoveries. The addition of more gears has demonstrated that the original machine—now clearly classi­fied as an astronomical analog computer—calculated an Earth-Moon relationship to a higher degree of accuracy than previously suspected. There is also revealed in the gearing ratios the Tropical Year for Venus, as well as hidden geo­metric formulas and the use of sacred numbers. Some of the new inscriptions found, especially on the machine’s front dial, confirm its division based on the Sothic Cycle of the Egyptians.

Even more remarkable, a number of the Antikythera gearing ratios and resulting cycles match those of the Maya calendar day periods. Was this link to Mesoamerica possibly through Atlantis, dating the original design of the mech­anism back twelve thousand years?

In the latest attempts at reconstructing the Antikythera machine, missing gaps in the mechanism suggest that there may have been as many as 70 gear-wheels all told. References in the device’s Greek inscriptions indicate that part of the missing gearing had been utilized to calculate the positions of the planets Mercury, Venus, and Mars; and there is good additional evidence that other gears were employed to show the movements of the outer known planets as well. If further research proves this possibility to be true, then the device would have also served as a miniature planetarium.

Above and beyond even this, researcher Richard Sanders, writing in Science and Technology Magazine, stated his belief that the reason why the Anitkythera device focused so much attention on calculating the movements of the Moon was that it was used as an instrument for finding longitude. This anticipated similar mechanical developments for measuring longitude which would not appear in Europe until the eighteenth century.

From the latest findings by the project and their detailed analysis of the Greek script employed, it is now calculat­ed that the present form of the computer was built between 150 and 100 B.C.E. This time period pre-dates Posidonius and Geminus, and points back instead to the influence of the early astronomer Hipparchus of Rhodes. The device used lunar calculations based on Hipparchus’ theories concerning the movements of the Moon, so he may have had a direct hand in its design. Or is it possible he learned about the lunar movements by studying the mechanism, already existing in his lifetime?

A number of experts have also voiced their opinion that the computer’s overall design was based on the heliocen­tric concepts of Aristarchus of Samos, going back to the fourth century B.C.E. Aristarchus’ belief that the Sun was the real center of our planetary system fell out of favor before Aristotle’s more predominant theory of geocentricity, yet was eventually proven the more correct by Copernicus, Galileo, and Kepler almost two thousand years later.

But again, we may well ask the question, which had come first, the precocious genius of Aristarchus or the mech­anism?

What experts of the Antikythera machine are slowly beginning to realize is that the device is far too sophisticated to have been a one-time fluke of technology, merely the product of a single person who happened to be far ahead of his contemporaries. Both the advanced mechanical as well as the astronomical knowledge exhibited in its design and functions could only have been the result of an extraordinarily long period of experimentation and observation, as well as the intelligent cooperative input of untold numbers of generations. Yet nowhere among any of the known classical ancient civilizations, do we find evidence for such a background.

However, we know it had to have existed somewhere in the unknown past, and that it was inherited by the Hellenic leading thinkers and experimenters who could barely understand it themselves. This undisclosed body of mechanical wisdom was later transmitted to the medieval Arabic world, most likely through surviving Greek manuscripts, where it reappeared in such Islamic works as the ninth century Book of Ingenius Devices by Banu Musa, and the eleventh century astronomical instruments of Al Baruni.

Hopefully, still more study of the original Greek computer may one day provide us with the answers. As research­er-writer Rob S. Rice concluded: “The Antikythera device’s very existence should prompt us to something besides skepticism. Only when all the implications of its discovery are understood and acted upon, then modern scholarship shall truly be said to have understood the Antikythera technology.”

Copyright 2009. Joseph Robert Jochmans. All Rights Reserved. Visit our website at:

By Joseph Robert Jochmans, Lit.D

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