The Antikythera Mechanism: A Shocking Discovery from Ancient Greece.

In 1901, some divers looking for sponges, near the island of Antikythera, found the remains of a clockwork-like mechanism in the wreck of a ship that sank approximately 2,000 years ago.

Its complexity and importance were not understood until decades later. It is believed to have been made in the years 100–150 I.H. Technological artifacts of similar complexity did not reappear until hundreds of years later. Jacques-Yves Cousteau visited the wreck in 1978, for the last time, but he did not find any other remains of the Antikythera mechanism. Professor Michael Edmunds of Cardiff University, leader of the latest study in this area, said at the time:

“This mechanism is extraordinary, it is the first of its kind. Its design is flawless and its astronomical calculations are correct. The internal mechanism is downright amazing. Whoever made this mechanism did so with immense care and meticulousness — if we refer only to its historical value and rarity, I must admit that this mechanism is more valuable than the Mona Lisa.”

How old is the Antikythera mechanism?

Currently, the mechanism is in the custody of the National Museum of Archeology in Athens, which presents it in the Bronze Collection. Although it is in a very bad condition due to the 2,000 years spent underwater, the mechanism, its gears, and the inscriptions on it force researchers to revise their opinion about the level of complexity of ancient Greek science. The mechanism comes in the form of a box that has several dials on the outside, and a complex set of gears inside, very similar to that of the mechanical clocks of the 18th century.

Antikythera Machine mechanical model. Photo by I, Mogi.

The dials are protected by the doors, and on all free surfaces of the box, doors, and dials, the instructions for use and construction of the device were written. There is a consensus among specialists, the mechanism was built in Greece because all the instructions on it were in Greek. Another 20 gears were recovered, including a sophisticated assembly of gears mounted on a rotating plate and functioning as an epicyclic system. Certain functional characteristics of the mechanism require even greater attention. All the metal components of the mechanism appear to be cut from a single sheet of bronze approximately 2 millimeters thick. All gears have teeth made at an angle of 60 degrees, and the size is identical, the wheels fit together without problems.

It appears that the mechanism has been repaired at least twice, the main wheel spoke has been straightened, and a broken sprocket tooth has been replaced. This tells us that the car has worked. More recently, in the light of recent discoveries, it seems that the concept of the mechanism comes from the colonies of Corinth, something that could make possible a connection with Archimedes. The real reasons why he is on that ship are not known. Those who have studied this case say that it is possible that the ship transported the mechanism to Rome, together with other precious things stolen from the island to be included in Caesar’s triumphal parade.

A reconstruction of the mechanism, made and donated to the museum by Derek de Solla Price, is also available to the public. Other reconstructions can be found at the American Computer Museum in Bozeman, Montana, and the Children’s Museum of Manhattan in New York and Kassel, Germany. The reconstruction of the Antikythera mechanism is the result of the research of Professor Derek de Solla Price, in collaboration with the Demokritos National Center for Scientific Research, and the physicist C.H. Karakalos, who made the x-ray tomography of the original, after which the copy of the mechanism was made.

Model of the Antikythera mechanism. Photo by Marsyas.

The mechanism represents one of the most ancient and complex scientific computers. Although its flawless construction suggests the fact that there were other mechanisms before it, these mechanisms were not discovered, its design was based on astronomical and mathematical theories developed by Greek astronomers, somewhere between 100–150 I.H. One hypothesis of the origin of the mechanism says that it was built at an academy founded by the Greek Stoic philosopher Posidonius on the island of Rhodes, which at the time was an important center of astronomy and mechanical engineering, and that it is possible that the astronomer Hipparchus was the one who designed it the mechanism because it contains a lunar mechanism that works based on Hipparchus’ theory of lunar movement.

The mechanism is remarkable because of the level of miniaturization and the complexity of its parts, which are at the level of 18th-century clocks. It contains 30 gears whose teeth are formed using equilateral triangles. When a date was entered (using a crank that was not found), the mechanism calculated the position of the Sun, and the Moon, as well as other astronomical information about other planets. The purpose of the device was to locate the celestial bodies, taking into account the celestial sphere (an imaginary rotating sphere, which is concentric and coaxial with the Earth) and the position of the observer on the surface of the earth, it is clear that it was based on the geocentric theory.

The mechanism has 3 dials, one at the front and two at the back. The back dial has two concentric graduated scales. The outer scale is divided into 365 segments, each segment representing a day from the Egyptian calendar of the Sothic year (In Egypt the Solar Calendar (Soltis-Sirius) had 365 days, being shorter than the astronomical calendar). This scale was used to compensate for the effect of the quarter day of the year (there are 365.2422 days per year), it was given back by one day every 4 years. But the Julian calendar, the first calendar that appeared in the region that also indicates leap years, appeared only in 46 I.H. That is, almost a century away from the period in which it is believed that the mechanism was built (at the same time, the leap year was erroneously calculated until the first century). The inner staircase has the signs of the Greek zodiac as graduations, divided into degrees.

The gears of th mechanism italic script mean that there may have been a gear there, but it was not found. Photo by Lead holder.

The front dial probably had at least 3 indicator hands, one showing the date, and the other two indicating the position of the Sun and the Moon. The lunar indicator was set in such a way as to indicate the first anomaly in the Moon’s orbit. It can be assumed that the Sun indicator had a similar setting, but the parts of this mechanism (if it existed) have not been found. The front dial has a second mechanism attached, a spherical model of the Moon, which indicates the lunar phases.

In the inscriptions on the mechanism, there are some references to the planets Mars and Venus, it would not have been who knows how much weight for the manufacturer of the machine to add the necessary components to calculate the positions of these planets. It is speculated that the mechanism would have been able to represent and calculate the position of all 5 planets known to the Greeks. But the parts of this planetary mechanism have not been found. The front dial also includes a parapegma, an ancestor of the modern almanac, which was used to keep track of the sunrise and sunset periods of certain stars. It is believed that each star is identified by the Greek characters related to the details written on the mechanism.

The dial at the top of the back of the machine has the shape of a spiral, with 47 divisions at a turn, it shows the 235 months of the 19-year Metonic cycle (the 19 years, after which the phases of the Moon repeat at approximately the same calendar dates). This cycle is important in correcting calendars.

The dial at the bottom of the back of the device is also in the form of a spiral, with 225 divisions that represent the saros cycle (a period equal to 18 years 11 days 8 hours, after which solar and lunar eclipses occur periodically It has a duration of 223 synodic revolutions, i.e. 242 draconic revolutions or 239 anomalistic revolutions); at the same time, there is an auxiliary dial in the same place that represents the 54 years of the Saros triple cycle (Exeligmos).

The Antikythera Mechanism Research Project, whose staff is composed of experts from Great Britain, Greece, and the United States, detected in July 2008 the word “Olympia” on one of the dials which were believed to represent the 76 years of the Caliphic cycle (76 years), as well as the name of other games in Ancient Greece, it was probably used to keep track of the dates on which the ancient Olympic games took place.

According to BBC reporters:

“The four sectors of the dial are inscribed with the number of a year and the names of two Panhellenic competitions: Olympic games from Isthmia, Olympia, Nemea, and Pythia; and with the names of two other less important competitions: Naa (which took place in Dodona), the name of the second competition has not yet been deciphered”.

Those who designed the mechanism did not need a theory of planetary motion to calculate planetary positions. The Babylonian “System B” (tables of values ​​that indicate the astronomical positions of the heavenly bodies according to the chosen period) contains the mathematical formulas used to calculate the planetary positions, this system which was taken over by the Greeks, and was created in the year 260 I.H. or maybe even in the year 500 I.H. There is a huge scientific and cultural gap between the educated elite, but with few members, who understood the basic rules of planetary, solar and lunar movements and the common people who were ignorant in these respects. Many of the ancient references left by Cicero, Pliny, Plato, Seneca, Ptolemy, etc., indicate that ordinary people considered eclipses of the moon and the sun to be supernatural events that they feared: “it is easy for the ignorant to imagine that everything has become confusion and death”.

What was the Antikythera mechanism used for?

– the creation of an astrological chart, for which it was necessary to know or find the configuration of the sky at a given moment. To make these calculations manually, a large volume of work and time is needed, therefore a mechanism like this would have considerably eased the work of an astrologer.

-establishing the dates of religious festivals that were related to certain astronomical events.

– the correction of the calendars, which were based on both the lunar cycles and the solar year.

The device may be exposed to the public, perhaps in a museum or a public hall in Rhodes. The island was known for exhibiting its mechanical engineering products, especially automata (the ancient form of robots), which were one of the island’s specialties.

Since the mechanism has a small size, it could even be compared to a modern laptop, we can deduce that the manufacturer emphasized the mobility of the mechanism, not a mechanism that would be exposed to the public in a fixed place. The doors behind which the device was closed when it was not in use have almost 2,000 characters written on them, it is believed that they are the instructions for use. Attaching this “user manual” to the mechanism means that the mechanism itself involves transport and personal use. This “manual” suggests that the mechanism was built by a scientific expert and a mechanic so that it could be used by a non-expert traveler (the text also provides information associated with known geographical locations of the Mediterranean area).

What did the Antikythera mechanism do

It is unlikely that the mechanism will be used for navigation, because some of the data it provides, such as the periods when eclipses occur, are useless for navigation. And the wet and salty environment would have led to the corrosion of the gears in a very short time, making them useless.

On July 30, 2008, researchers stated that the mechanism indicates the Metonic calendar, predicts solar eclipses, and calculates the dates on which the ancient Olympic games took place. The inscriptions on the mechanism matched the names of the months in the calendars used in Illyria and Epirus, in northwestern Greece, and with those used on the island of Corfu.

To better understand the importance of this discovery, we should research the history of the mechanical clock to be able to find essential analogies for the Antikythera mechanism and to be able to evaluate its importance. Unlike other mechanical mechanisms, the watch did not evolve from simple to complex. The oldest clocks we have information about are very complex. All the evidence points to the fact that the clock was originally an astronomical device, which incidentally also indicates the time.

Along the way, the function of indicating the time became more important, and the astronomical function lost its value. Behind the astronomical clocks of the 14th century, there is a long line of mechanical models of astronomical theory, at the end of which we find the Antikythera mechanism. After him, we find mechanical instruments and calculators from Islam, China, and India.

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