Abstract

Astronomy is the oldest science, as humans have been watching the sky attempting to understand their environment to survive. This eventually led them to try and explain their existence in the Cosmos, hence Philosophy. This was the birth of Humanity. It coincides with the beginning not only of astronomy and science, but philosophy, too.

Astronomy develops in all longitudes and latitudes, as it is an applied and practical science, necessary to regulate life and social rhythms in ancient societies. Gradually humans notice astronomical phenomena and try to understand the regularity of motions of celestial bodies, stars, Sun, Moon and planets, they develop calendars, mathematics and astronomy becomes science.

The Antikythera Mechanism is the oldest known astronomical instrument and astronomical computer that we have in hands, probably made between 150 and 100 BC, by a Greek mechanic, under the guidance of a great astronomer with excellent knowledge of mathematics. There must have been several other similar mechanisms before this one some perhaps equally complicated and advanced, like the two made by Archimedes, and Posidonius, mentioned by Cicero. The Antikythera Mechanism, the oldest scientific instrument with divisions and very complicated scales that it is also an accurate astronomical computer. Reading the manual we understand that as an instrument it could have been used to do observations as it has trunnions and the constructor mentions sun ray and how to measure an angular distance between two astronomical bodies.

As a computer it could be used to keep several types of accurate calendars (solar, lunal and lunisolar) based on the Egyptian solar year, the Meton and Callippic cycles of 19 and 76 years, and the Saros and Exeligmos cycles that have been used to predict eclipses. The mechanism is made of bronze gears with several trains and axles, that move several pointers along several scales, some circulars and two large scales made of thick Archimedes spirals divided in months, lunations, which contain inscriptions about predicted eclipses. The mechanism shows with pointers the position of the Sun and the Moon and the phase of the Moon during the month. An astonishing discovery was that the motion of the Moon follows to a good approximation the second law of Kepler.

It is very possible that the astronomical computer predicted the position of the planets, as there are several terms concerning planetary motions and the names of Aphrodite (Venus) and Hermes (Mercury) and this is not a surprise as the Planetarium was one of the two instruments made by Archimedes, almost a century before the Antikythera Mechanism. There is a possibility, as there are indications, that the mechanism was an anaphoric clock.

The presentation (PDF)