Marine archaeologists initially assigned a bronze mechanism from a coastal excavation a date at least a century earlier than that of the Antikythera device, which would extend the known history of complex astronomical gearwork. The estimate depended on pottery recovered beside the mechanism, but the surrounding sediment later proved to have been disturbed. CT scans revealed an arrangement of gears capable of modeling lunar cycles, while wear on several gear teeth was consistent with repeated operation. The scans cannot restore the lost chronological context. Yet an account of the mechanism as an ingenious design that never became a working instrument would have to explain the wear.
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