Saturday, April 11, 2009

The Mechanism of Antikythera: The World's First Computer?

In 1901, a group of divers discovered a ship wreck near the Greek island of Antikythera. Inside, they found some chunks of lime which apparently contained pieces of copper. Later, close examination by scientists revealed gears, scales, a crank handle and inscriptions.

The mechanism of Antikythera.

Today, the machine is assumed to have been one of the world's first analog computers. Dr. Derek J. de Solla Price examined the machine in 1959, and his conclusions were a sensation. The findings demonstrated that it has been used to calculate the time of sunrise, moon phases, the dates of equinoxes and solstices and even the movements of the five planets known to the Greeks at that time.

The time when the machine was manufactured was dated to be the first or second century BC. It was probably assembled on the Greek island of Rhodes, which was well-known in antiquity for its skilled engineers.

Derek J. de Solla Price with a replica of the machine.

Given the supported functionality and the era of manufacture, the device is relatively small. On some attached door plates, it contained at least 2000 Greek letters - presumably instructions on how to operate the machine. This suggests that it was made to be moved easily from one place to another.

A remarkable property of the mechanism is the clever way how it uses gears to perform mathematical operations. However, gears were known long before that – already Aristotle documented them in the fourth century BC.

Perhaps the most fascinating mechanical feature of the machine is that it seems to employ a differential. This device, which is today commonly used in automobiles, was likely not discovered again until the modern era, when Onésiphore Pecqueur patented it in 1827. Therefore, the real inventor probably was a craftsman from Rhodes.

A sketch of the mechanism.

The machine seems not to have been used to aid navigation – many of the functions are not needed for this purpose, and contact with water would have corroded the fine parts it was composed of. A much likelier theory is that it was used for astrology or determining the dates of religious festivals influenced by astronomy. It therefore simplified the otherwise tedious calculations carried out by hand.

The mechanism of Antikythera is historically significant. It demonstrates how scientifically advanced the world of antiquity really was, contrary to popular perception.


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