Antikythera Mechanism: A 2000 Year Old Computer



Named for many years as Oopart, out of place artifacts since the first knowledge of mechanisms of cogwheels, like the clocks, dating from century XIV and the antiquity of this artifact would be estimated around III century BC. But who could imagine that thanks to the ancient literature would open an interesting answer to the enigma? And that for me, personally, it fascinates me as much or more than if it were really an oopart. Do you believe that The Library of Alexandria has a leading role in this story?

The Antikythera Mechanism is an ancient analogue computer designed to predict the position of the Sun, Moon and some planets, which made it possible to predict eclipses and also predict the exact date of six ancient Greek competitions like the Olympia Games, the Pythian Games, the Isthmian Games, the Nemean Games, the Dodona Games and those on the island of Rhodes. It consists of a set of gears of bronze cogwheels with signs and astronomical inscriptions in ancient Greek, Corinthian-Syracusan dialect.

The Antikythera mechanism, despite no equal has up to the realization of the first subsequent mechanical calendars to 1050, that remains perfectly integrated in the knowledge of the late Hellenistic period. There are represented only the five planets visible to the naked eye and the material used is an easily workable metal.

After the knowledge of this technology was lost some time in antiquity, technological artifacts that would approach the complexity and skill of construction of this instrument did not appear again until the development of astronomical clocks in Europe that began towards XIV century.

It was discovered 45 meters below the water near Glyfadia between the remains of a shipwreck near the Greek island of Anticitera, between Kythira and Crete, and believed to date from 205 BC. At the beginning of the 20th century, a fisherman, Elias Stadiatis, a sponge collector, was diving on Antikythera Island, north of Crete, Greece, when he discovered a wreck below sixty meters deep near the water The Greek island of Anticitera.

He described it as a pile of corpses and horses. He returned to the surface thinking that the excess carbon dioxide was making him hallucinate. What Stadiatis did not know was that he actually encountered the wreck of a Roman ship carrying hundreds of Greek pieces from the third century BC. In it, amphoras, statues of marble and copper, greco-roman pottery and a series of coins were found that allowed to date the shipwreck between the years 85 and 60 BC.

After the rescue work was completed a year later and when its classification was carried out, the Greek archaeologist Valerios Stais noticed the presence of a strange object. What Valerios recovered from the bottom was a kind of mechanism built in bronze and composed of thirty gears. But how could anyone create more than two millennia a sophisticated machine whose degree of complexity and mechanical perfection would not arise again until the fourteenth century?

On the front face of the mechanism is a ring-shaped disk, fixed to the structure, representing the ecliptic and the 12 zodiacal signs marked in sectors of 30 degrees. This agrees with the Babylonian custom of assigning a twelfth of the ecliptic to each zodiacal sign evenly, though the constellation boundaries were variable. Out of the disk is another ring that is rotating; This is marked with the months and days of the Egyptian calendar: 12 months of 30 days plus 5 epagomenal days.

The months are marked with their respective Egyptian names transcribed to the Greek alphabet. The first task is to rotate the Egyptian calendar to match the signs of the zodiac in the artifact with the current ones. The Egyptian calendar ignored the 5 epagomenal days, reason why it advanced completely by a zodiacal symbol in approximately 120 years.

The mechanism was operated by the rotation of a crank (currently lost) that was connected by means of a gear in the form of a crown to the larger gear, the gear with four teeth in the front of the fragment Ha called b1. This moved the cursor on the front disk that would select the correct day of the Egyptian calendar. The year was not selectable, so it was necessary to know the currently selected year or to look for the cycles with the help of the various calendar cycle indicators on the reverse of the Babylonian ephemeris tables for the day of the selected year, since cycles Of the calendar are not synchronous with the year.

The crank moved the date cursor for 78 days each full rotation. This facilitated the selection of a particular day if the mechanism was in good condition. The action of rotating the handle of the crank would cause the interconnected gears within the mechanism to rotate; This resulted in the simultaneous calculation of the position of the Sun and Moon, the lunar phase, eclipse, calendar cycles and possibly the position of planets.

In zodiacal disks there are also unique characters in certain points. They are related to a Greek almanac, precursor to the modern almanac inscribed on the front face behind the disks. These mark the locations and lengths of the ecliptic for specific stars.

In the old Literature already appear narrated similar mechanisms. If this is an example of the devices created by Archimedes and described in his texts lost in the fire of the library of Alexandria or a device based on his discoveries or has something to do with it is debatable.

It is unlikely that any of these machines was the mechanism of Anticiter found in the wreck since both the devices manufactured by Archimedes and mentioned by Cicero were located in Rome at least 30 years after the estimated date of the shipwreck and the third was almost with Certainty in the hands of Posidonius for those dates. So we know there were at least four such devices.

Modern scientists who have reconstructed the mechanism of Anticite also agree that it was too sophisticated to have been a unique device. It is likely that the Anticite mechanism was not unique, as Cicero's references to these mechanisms show. This supports the idea that there was a tradition in ancient Greece of complex mechanical technology that was later, at least in part, transmitted to the Byzantines and to the Islamic world, where mechanical devices of complex gears, although less elaborated than the mechanism of Anticither, were constructed during the times.

Fragments of a mechanical calendar attached to a solar clock, from the 5th or 6th century of the Byzantine Empire have been found. It is possible that this medieval technology was transmitted to Europe and contributed to the development of mechanical watches. To see this mechanism as an oopart is interesting, but knowing everything is simply fascinating.

Imagine the intelligence, talent and wisdom of the men creating such an advanced and difficult mechanism. Probably, it had already disappeared at the time of Arab domination, although some writers comment that the caliph Umar ibn al-Khattab ordered the destruction of thousands of manuscripts. Regardless of the guilt of Christians and Muslims, the end of the library should be located at an indeterminate time in the third or fourth century, perhaps in 273, when the emperor Aureliano took and sacked the city, or when Diocletian did the same.

The library-daughter of the Serapeo, successor of the Great Library, was expelled, or at least emptied, in 391, when Emperor Theodosius ordered the destruction of the pagan temples of the city of the Ptolemies. The pagan culture was secular and tolerant precisely because they were polytheistic who believed in the god they wanted, but let others believe in theirs.

Pagan culture had until then developed a thought and a scientific practice centered on the observation of natural events and devoid of physical phenomena and fideistic axiomatic impositions resulting from absolute, revealed truth absolutely beyond human comprehension and control, and it was dedicated to understanding the nature and the relationships between the forces at play. This was the sense of that wonderful period of science and culture development, which was Hellenism.

Although generally referred to as the first analog computer, the quality and complexity of the mechanism's manufacture suggests that it has undiscovered predecessors made in the Hellenistic period.

In this period, instead, in Europe and around, followed the long dark ages of the decline and obscurantism with the protagonists of that science were killed and massacred and their work dispersed and destroying all traces and evidence of their works of their studies and the many wonderful insights that perhaps would have saved 1,200 years of backwardness, suffering, atrocities and miseries in the entire globe.

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