Categories: antiquities, archaeology, Babylon, Greece
An article in Nature asserts that the 2000 year old ancient Greek mechanical wonder known as the Antikythera mechanism, which calculates astronomical and planetary motions, was built using mathematical theories that originated centuries previously by the Babylonians. This was suggested from previous studies published in 2006, but an intriguing hypothesis by astronomical historian James Evans at the University of Puget Sound in Tacoma, Washington, suggests how the mechanics may have influenced Greek theories of cosmic motions:
Evans argues that even the clearly epicyclic gearing of the Moon display may model Babylonian arithmetic, not Greek geometry. The amplitude of the variation encoded by the pin-and-slot mechanism is larger than that used by Hipparchus in his eccentric model, he points out, and is closer to the amplitude used in the lunar algorithms of the Babylonians. “Perhaps a mechanic tried to represent the variations in the Moon’s speed according to the Babylonian theory using gears,” he says — and hit upon an epicyclic arrangement.
In other words, epicycles were not a philosophical innovation but a mechanical one. Once Greek astronomers realized how well epicyclic gearing in devices such as the Antikythera mechanism replicated the cyclic variations of celestial bodies, they could have incorporated the concept into their own geometrical models of the cosmos.