Back in November of 2006 I blogged about new research into the Antikythera device, a Greek 1st century BC astronomical simulator. The news at the time was that:
… computer-aided X-ray tomography … has allowed a team of scholars to understand better how the thing worked and to decipher more of its many inscriptions. Using a large number of cogged wheels and gears, the mechanism was designed to simulate and predict the movements and interrelationships of the more important heavenly bodies.
Now, a new paper in Nature presents further insights: the device
… unites abstruse astronomical determinations of time with the calendar of civic society. Another ancient Greek calendar cycle, called the Metonic cycle, was established to cope with the incommensurability of the lunar cycle and the solar year — the period of Earth’s rotation around the Sun, as determined, say, by the time between successive summer solstices. One Metonic period is equal to 235 lunar months, which is almost exactly 19 solar years. The Metonic cycle, thought previously to be used only by astronomers, is represented on a dial on the Antikythera Mechanism. But this dial now turns out to be inscribed with the names of months in a regional calendar used in Corinthian colonies in northwest Greece — providing evidence that the device was used for mundane reckonings, and giving a surprising clue to its origin.
The team has even identified a dial that tracks a four-year cycle, most likely that of the Olympiad!
Update 5 October: Tobias points to an amazing short film about the new results.