Gears Within Gears Within Gears

What the Antikythera mechanism says about the technology and culture of Western antiquity.

A recent paper has laid out a complete reconstruction of the Antikythera mechanism, which was an astronomical computer made around 50 to 200 BCE. It is a machine of breathtaking scope and ambition, far beyond what the ancient world was thought capable of- a detailed model of the motions of all the planets of the day, sun, moon (with phases), plus on the back, detailed predictions of solar eclipses and, in true sports page fashion, schedules for the most popular panhellenic games. All this was available decades in advance, though a true modeling computer that the user could wind through at will, forward or back. As a bonus, an instruction manual was inscribed on the back.

An artist's rendition of the current researcher's proposals about the front face of the Antikythera computer. The moon (black and white) revolves around the earth at center, with phases reflected in its rotation. Outer rings and pointers successively portray the Sun, Mercury, Venus, Earth date, Mars, Jupiter, and Saturn. A knob at the side would have allowed the user to run it.

To understand the detailed mechanisms and proposals of this research group, watch their video. No one would have known about this technology had not some sponge divers found a ~75 BCE wreck off the coast of Antikythera in 1900. One of the many artifacts was a lump of bronze, with a clearly mechanism-like structure but heavily corroded. Indeed only a third of the original was ever found, and it has taken all this time, including recent intensive X-ray examinations of its inner workings and inscriptions, to figure out its full splendor.

A partial rendition of the computer's inner workings, with gears noted with their numbers of gear teeth. Eccentric motions were provided by bars connected to gear-mounted pins off-set from the gear's pivot center.

One of the more puzzling aspects of this device, on a purely technological level, is how the precise machining was done, all in bronze. The front face displays at least nine separately moving dials or pointers, each driven by one of a set of nested tubes making up the central shaft of the computer. Could the Hellenistic Greeks cast bronze to this kind of uniformity and thinness? Or did they have lathes with such precision? What can be assumed is that this mechanism is not alone, and must have been the product of an ongoing tradition of precision device manufacture- a long technological evolution that accumulated the numerous ingenious solutions and remarkable miniaturization evident in this device. How could such a tradition have otherwise so thoroughly evaded historians and archeologists? And what became of this tradition into Roman times?

The astronomy that this device is based on has its roots with the Babylonians, who were avid readers of the skys and its many cycles. The gears within accord with various grand cycles with which key events, like the position of the moon or planets, recur with regularity. For example, the Saros cycle is when the Earth, Moon, and Sun line up for an eclipse, and recurs every 18 years, 11 1/3 days. The gearing in the Antikythera mechanism goes through five different pairings to come up with the 940/4237 ratio that approximates the 18 year cycle every four turns of the crank. The Greeks naturally contributed their own astronomical theories, such as a conviction in the regularity / sphericity of the planetary orbits, despite their wayward motion.

All this tells us strongly that these ancient people were every bit as inventive and thoughtful as we are. But they had very different cultural conceptions and resources to work with. The most frustrating aspect to this amazing story is why this inventiveness did not lead to a more general technological revolution, instead sputtering out with the fall of Rome and the fallow Dark Ages, before technological development resumed at a high level during the later Middle Ages.

I think the answer needs to be put down to the class relations and nature of work in the ancient world. Capitalism certainly was not lacking. Antiquity was just as capitalistic as modern times, with an extremely free business sector able to finance wide-ranging trade and manufacturing operations, and merchants occupying the pride of place in Greek and Roman fora- the malls of their time. The story of Crassus extorting Romans of their burning properties in return for fighting the fire tells you all you need to know about the nature of capitalism in these times. It was red in tooth and claw. But that was not enough to foster technological development on a broad basis.

Rather, slavery and vast inequality made work a degraded, mean affair, beneath the dignity of aristocrats. Their minds were on government, law, military conquest, art, and philosophy. Anything but practical affairs of efficiency, improved production, and technological advancement. Work was secondary to power relations- the essence of a slave society. We have seen this in the Southern culture of the US under slavery. It was obsessed with pursuit of "refinements" and honor. Even though labor was expensive in the form of slaves, and its management a social imperative of the highest order, the idea of supplementing it or replacing it via technology does not seem to have been a high priority. The cotton gin was invented, not by a Southerner, but by Eli Whitney of Massachusetts.

It is a general problem of highly unequal societies, that the maintenance (and defense) of inequality takes on a large part of the mental space of the society, (particularly its educated elite), overtaking the motivations that in a more egalitarian society- where all participate in work and all are eager to adopt improved methods in the work they all share in- that promote the development and propagation of technological advancements. (Think of the revolutions in mechanized agriculture in midwestern America in the late 1800's.) In scholarship as well, the segregation of abstract philosophy and other written forms / stores of knowledge into ivory towers, as was common in Hellenistic culture, reflected the same cultural stratification and lack of concern with the day-to-day drudgery that formed the rather static basis of economic existence.

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