Does anyone here know what the fundamental _period_ of the antikythera device is? I.e., by all reports, this device is a "planetarium in a box". So how many years of simulated time does it take for this device to return to its initial configuration ? If we start the antikythera device in 70 B.C., which appears to be approximately the date of its demise, how far into the future can this device "see" ? Also, if the antikythera device really is a "planetarium in a box", and if it really does do a good job of modeling the known universe at the time, how come we can't tell _the exact date_ of its demise ? Let's assume that the device was used on a daily, weekly or monthly basis. Presumably, the position of the wheels would be indicative of the last time it was used. This is essentially equivalent to being able to determine the exact time of an earthquake from the position of the hands of clocks which stopped as a result of the earthquake.