A mechanical device that illustrates the relative positions and motions of the planets and moons in the solar system in heliocentric model. Typically driven by a large clockwork mechanism with a globe representing the Sun at the centre, and with a planet at the end of each of the arms.According to Cicero, the Greek philosopher Posidonius constructed an orrery, possibly similar or identical to the Antikythera mechanism, which exhibited the diurnal motions of the sun, moon, and the five known planets. Cicero's account was written in the first century BC.
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