Orrery (mechanism)

Orrery: Impressive early model of the Solar System, usually following Copernicus.

From opening of the nicely-illustrated Wikipedia entry:

An orrery is a mechanical model of the Solar System that illustrates or predicts the relative positions and motions of the planets and moons, usually according to the heliocentric model. It may also represent the relative sizes of these bodies; however, since accurate scaling is often not practical due to the actual large ratio differences, a subdued approximation may be used instead. Though the Greeks had working planetaria, the first orrery that was a planetarium of the modern era was produced in 1704, and one was presented to Charles Boyle, 4th Earl of Orrery – hence the name. They are typically driven by a clockwork mechanism with a globe representing the Sun at the centre, and with a planet at the end of each of the arms.[1]

In addition to an orrery's being a literal (if small and limited) clockwork universe, note that the most ancient example of something like an orrery is the "Antikythera mechanism," presented in its Wikipedia entry, with photographs, as "an ancient Greek hand-powered orrery, described as the oldest example of an analogue computer[,] used to predict astronomical positions and eclipses decades in advance. It could also be used to track the four-year cycle of athletic games" like, but apparently not identical to, an "Olympiad."[2]

It would go too far to trace the idea of a mechanistic universe back to ancient Babylonian astronomy, but by the time of Jesus of Nazareth and Augustus Caesar a mechanism could be imagined and built to subject astronomical events to human cognition. And by the time of the Scientific Revolution, a mechanism would be built illustrating astronomical phenomena and human theories about them, the orrery.

RDE, finishing, 24Aug21