Editing Antikythera mechanism (section)

===Accuracy===

Investigations by Freeth and Jones reveal their simulated mechanism is inaccurate. The Mars pointer is up to 38° wrong in some instances (these inaccuracies occur at the nodal points of Mars' retrograde motion, and the error recedes at other locations in the orbit). This is not due to inaccuracies in gearing ratios in the mechanism, but inadequacies in the Greek theory of planetary movements. The accuracy could not have been improved until {{Circa|160 AD}} when [[Ptolemy]] published his ''[[Almagest]]'' (particularly by adding the concept of the [[equant]] to his theory), then much later by the introduction of [[Kepler's laws of planetary motion]] in 1609 and 1619.<ref name=freeth-12 />

{{blockquote|In short, the Antikythera Mechanism was a machine designed to predict celestial phenomena according to the sophisticated astronomical theories current in its day, the sole witness to a lost history of brilliant engineering, a conception of pure genius, one of the great wonders of the ancient world—but it didn't really work very well!<ref name=freeth-12 />}}

In addition to theoretical accuracy, there is the issue of mechanical accuracy. Freeth and Jones note that the inevitable "looseness" in the mechanism due to the hand-built gears, with their triangular teeth and the frictions between gears, and in bearing surfaces, probably would have swamped the finer solar and lunar correction mechanisms built into it:

{{blockquote|Though the engineering was remarkable for its era, recent research indicates that its design conception exceeded the engineering precision of its manufacture by a wide margin—with considerable cumulative inaccuracies in the gear trains, which would have cancelled out many of the subtle anomalies built into its design.<ref name=freeth-12/><ref name="Auto82-43"/>}}

While the device may have struggled with inaccuracies, due to the triangular teeth being hand-made, the calculations used and technology implemented to create the elliptical paths of the planets and retrograde motion of the Moon and Mars, by using a clockwork-type gear train with the addition of a pin-and-slot epicyclic mechanism, predated that of the first known clocks found in [[Late antiquity|antiquity]] in medieval Europe, by more than 1000 years.{{clarify|date=April 2023}}<ref name="Auto82-44"/> Archimedes' development of the approximate value of [[pi]] and his theory of centres of gravity, along with the steps he made towards developing the [[calculus]],<ref name="Auto82-45"/> suggest the Greeks had enough mathematical knowledge beyond that of Babylonian algebra, to model the elliptical nature of planetary motion.

{{blockquote|Of special delight to physicists, the Moon mechanism uses a special train of bronze gears, two of them linked with a slightly offset axis, to indicate the position and phase of the moon. As is known today from [[Kepler's laws of planetary motion]], the moon travels at different speeds as it orbits the Earth, and this speed differential is modelled by the Antikythera Mechanism, even though the [[Ancient Greeks]] were not aware of the actual elliptical shape of the orbit.<ref name="Auto82-46"/>}}