The Antikythera Mechanism

The Antikythera Mechanism is the oldest computer we know. It's an ancient astronomical automaton, a specialized mechanical computer, probably a complex astronomical clock of 150 to 100 BC. The mechanism is not only a mechanical Cosmos but also a complex astronomical instrument that predicts all astronomical phenomena known in antiquity. It displays the positions of the Sun and the Moon and probably all the then known five planets. It predicts the time when solar and lunar eclipses occur (it predicts correctly even today) and also where they are visible on Earth.

It predicts the phases of the moon and the beginning of each lunar month in two lunar calendars that the Greeks and perhaps other nations used at the time. The phases of the Moon are predicted by various calendars of the mechanism, but mainly by the 19-year cycle of Meton that he developed during the time of Socrates and which from the 13th century is used it for Easter. The calendar that we found in the mechanism and is based on the cycle of 19 years of Meton and based on the names of the months it is an Epirotic calendar. The names of the months FINIKEOS, KRANIOS, LANOTROPIOS, MAHANEUS (Jupiter), DODEKATEUS, EUCLIOS ARTEMISIOS, PSYDREUS, GAMELIUS, AGRIANUS, PANAMOS, APELEOS coniside with the calendar of Corfu, Apollonia and Vouthroton and partly other Epirotic cities. There are many Epirotic calendars since each city-state had its own. Epirotic calendars belong to the large category Corinthian which are a subset of Doric calendars.

The mechanism determines when the Olympic Games will be held using another eight-year lunisolar calendar that is called Octaetiris. This calendar is based on the 8 year resonance period of the orbits around the Sun of the Earth and Venus and the Moon around the Earth. These celestial bodies are in an eternal complex minuet dance with 5 turns (orbits around the Sun) of Venus, 8 of the Earth and 99 of the Moon around the Earth. Octaetiris, as this period is called, contains two Olympics lasting 49 and 50 lunar months. The commencement of all the important games, the Olympic, the Pythian, Isthmian, Nemean, Naia and Alia are determined in accordance to the phase of the Moon (full moon) and the Solstices. I believe that this eight-year calendar is a prehistoric, probably pan-European calendar, used in the Minoan period in Greece, not only by the Cretans. Every city used a variant of Octaetiris to regulate political and agricultural life. This was probably the calendar of all Europe in prehistoric times. We know that the Scandinavians had this calendar the eight-year year until 1280 and they have been performing human sacrifices every eight years to mark the beginning of the new eight year period as in Greek mythology with Minotaur.
Like any scientific instrument, the mechanism is accompanied by a very detailed user manual that is written on copper sheets with very small, 2mm capital Greek letters almost identical to the ones we use today, on the doors of the mechanism.

The mechanism works with small well designed an cut gears. In the gears of the mechanism we read the mathematics and the laws of physics, as they understand them at that time, which the Greeks have established and used then to study celestial phenomena and to predict some of these phenomena that we have discovered that are displayed in the mechanism scientific scales,some circular and some spiral (Archimedes type).

Two unexpected discoveries that we have made are that the movement of the moon is given at variable speed with a very good approximation to Kepler's 2nd law, while a planetary gear gives very realistic position to the planet Jupiter using a spring, a coil curled around a part of the planetary mechanism that moves Jupiter for a few years.
Another big surprise was that we discovered in ancient texts that instruments like the mechanism in ancient times are called "PINAKIDION", ie tablet.
The mechanism may have been an astronomical clock working continuously with a weight and counterweight system, like cuckoo clocks, with a timed motion controller from a kind of float in a clepsydra, as Heron and others describe accurately.

The mechanism is an epitome of Greek philosophy and especially of Pythagorean philosophy based on mathematics and the natural philosophy of the Ionian Philosophers, like Thales, Anaximander, but also of Plato and Aristotle. Leucippus and Democritus. Our study proved that the Greeks in ancient times had advanced technology, based on science, astronomy, physics and mathematics., with which the Greeks have since expressed the laws of Nature.
When one realizes that the automatic mechanism does all this, one wonders how it is possible for humans, the Greeks in particular, to create such a mechanical Cosmos. The answer is simple. The Greeks had developed everything necessary to predict natural phenomena with good accuracy. They had developed appropriate mathematics to formulate the laws of physics with which they interpreted and in some cases of astronomical phenomena predicted satisfactorily. This is the greatest step humanity has taken, to understand and predict nature in terms of causality and the notion of laws of physics.

There must have been many similar "machines" from prehistoric times, because of course the mechanism was not made in one day. The so-called Minoan astronomical computer of 1800 BC is certainly the ancestor of the Antikythera Mechanism and later we have many machines in the east, south, and west over the centuries, until the Industrial Revolution. Similar mechanisms have always existed, albeit in small numbers, as they were expensive too. It was used by travelers, astronomers, philosophers, geographers, the military and as symbols of prestige by politicians and the rich.

The Antikythera Mechanism is perhaps the most special, unique and perhaps the most important of all exhibits of the National Archaeological Museum of Athens where we can admire it. It is on display in a magnificent showcase since the time it was found in a huge ancient shipwreck that sunk around 60 to 80 BC. It has been discovered by Symian sponge-divers at a depth of 45 meters. It was diver Elias Stadiatis with captain Dimitris Kontos, near the Potamos port of Antikythera, on Holy Tuesday, April 4, 1900 who discovered a huge 60 metres long ship, covered by lead, full of antiquities, a floating museum, that was on its way to Rome with lute from Greece. The two small boats, "Euterpe" and "Kalliope" stopped due to rough seas on their way for sponges to Livya. The Mechanism was discovered a little later, probably in March 1901, by the skilled diver Elias Stadiatis during the world's first and largest marine archaeological excavation. The mechanism was pointed out by Archaeologist ValeriosStais at the Museum on May 17, 1902.
The Mechanism is currently performing a very important double task. Educational, because it teaches a lot to young people, the importance of science in understanding and predicting nature, it also teaches the usefulness of mathematics, technology, physics, history and even philosophy. At the same time, it is an excellent ambassador of Greek culture that nobody forgets.

We have organized many very successful exhibitions and speeches around the world, at NASA and UNESCO, in many archeological museums, universities, colleges, schools in all countries and much more in Greece. In the exhibitions we present the mechanism and together with Greek culture for the benefit of the young people and maximum visibility of Greece. The exhibition is available in 13 languages. Our exhibitions and lectures around the Globe help young people to gain self-awareness and, above all, self-confidence that they so lack. The mechanism teaches that people can achieve whatever they want, as long as they set high goals, they plan based on knowledge, science and to carry out methodically. With the exhibitions and talks we also try to help young people get to know who they are, where they come from and where they can go, that they can plan their future, to set high goals, plan and to accomplish them.

Xenophon Mousas, University of Athens, May 2020

Mr Xenophon Moussas is Professor of Space Physics (ret.) Department of Astrophysics, Astronomy and Mechanics Faculty of Physics, School of Science National and Kapodistrian University of Athens and one of the Founder Members of the initial academic team of the Antikythera Mechanism Research Project