In 1900, on the eve of Easter, two ships of sponge catchers returning from the coast of Africa anchored off the small Greek island of Antikythera (Antikythera) in the Aegean Sea, located between the island of Crete and the southern tip of mainland Greece - the Peloponnese. There, at a depth of about 60 meters, divers discovered the remains of an ancient ship.
Sponge Divers, 1900
The following year, Greek archaeologists, with the help of divers, began researching the sunken ship, which turned out to be a Roman merchant ship that wrecked around 80-50. BC. According to the most probable hypothesis, the ship went from the island of Rhodes, most likely to Rome with trophies or diplomatic "gifts". As you know, the conquest of Greece by Rome was accompanied by the systematic export of cultural property to Italy.
Among the objects raised from the sunken ship, there was a shapeless lump of corroded bronze, taken at first for a fragment of a statue. In 1902, archaeologist Valerios Stais began to study it. Having cleared it of lime deposits, he, to his surprise, discovered a complex mechanism, like a watch, with many bronze gears, remnants of drive shafts and measuring scales. We also managed to make out some inscriptions in the ancient Greek language.
Having spent 2,000 years on the seabed, the mechanism has come down to us in a badly damaged form. The wooden frame on which it was apparently attached has completely disintegrated. The metal parts are severely deformed and corroded. In addition, many fragments of the mechanism have been lost. In 1903, the first official scientific publication was published in Athens with a description and photographs of the Antikythera mechanism, as this device was called.
It took painstaking work to clean the device, which lasted more than one decade. Its reconstruction seemed almost hopeless, and it remained poorly understood for a long time until it attracted the attention of the English physicist and historian of science Derek J. de Solla Price. In 1959, the Scientific American magazine published an article by Price, "The Ancient Greek Computer," on the Antikythera Mechanism and a milestone in his research.
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Carried out in 1971, radiocarbon analysis and epigraphic studies of the inscriptions made it possible to establish that this device was created in 150-100 BC. Examination of the mechanism using X-ray and gamma radiography provided valuable information on the internal configuration of the device.
All surviving metal parts of the Antikythera mechanism are made of sheet bronze 1-2 millimeters thick. Many of the fragments are almost completely converted to corrosion products, but in many places the delicate details of the mechanism can still be discerned. Currently, 7 large and 75 small fragments of this mechanism are known.
Even at the initial stage of the study, thanks to the preserved inscriptions and scales, the Antikythera mechanism was identified as a kind of device for astronomical needs. According to the first hypothesis, it was some kind of navigation tool, possibly an astrolabe - a kind of circular map of the starry sky with devices for determining the coordinates of stars and other astronomical observations, the inventor of which is considered to be the ancient Greek astronomer Hipparchus (c. 180-190 - 125 BC). BC).
However, it soon became clear that the level of miniaturization and complexity of the Antikythera mechanism is comparable to the astronomical clock of the 18th century. It contains over 30 gears with teeth in the shape of equilateral triangles. This high complexity and impeccable workmanship suggests that it had a number of predecessors that have not been discovered.
According to the second hypothesis, the mechanism was a "flat" version of the mechanical celestial globe (planetarium) created by Archimedes (c. 287 - 212 BC), which was reported by ancient authors.
The earliest mention of the Archimedes' globe dates back to the 1st century BC. In the dialogue of the famous Roman orator Cicero "On the State", the conversation between the participants in the conversation turns to solar eclipses, and one of them says:
I remember how I once, together with Guy Sulpicius Gall, one of the most learned people of our country, was visiting Mark Marcellus … and Gallus asked him to bring the famous "sphere", the only trophy with which Marcellus' great-grandfather wished to decorate his home after the capture of Syracuse, a city full of treasures and wonders.
I have often heard people talk about this "sphere", which was considered a masterpiece of Archimedes, and I must confess that at first glance I did not find anything special in it. More beautiful and better known among the people was another sphere, created by the same Archimedes, which the same Marcellus gave to the Temple of Valor.
But when Gallus began to explain to us the structure of this device with great knowledge of the matter, I came to the conclusion that the Sicilian had a talent greater than what a person can have. For Gallus said that … a solid sphere without voids was invented a long time ago … but, - said Gall, - such a sphere on which the movements of the Sun, Moon and five stars, called … wandering, were represented, could not be created in the form of a solid body.
Archimedes' invention is amazing precisely because he came up with how, during dissimilar movements during one revolution, to preserve dissimilar and different paths. When Gallus set this sphere in motion, it so happened that on this ball of bronze the moon replaced the sun for as many revolutions as in how many days it replaced it in the sky itself, as a result of which the same eclipse of the sun occurred in the sky of the sphere, and the moon entered the same meta where the shadow of the earth was, when the sun came out of the region … (Lacuna).
Nothing is reliably known about the internal mechanism of the celestial globe of Archimedes. It can be assumed that it consisted of a complex system of gears, like the Antikythera mechanism. Archimedes wrote a book about the device of the celestial globe - "On the making of spheres", but, unfortunately, it was lost.
Cicero also writes about another similar device made by Posidonius (c. 135 - 51 BC), a Stoic philosopher and scientist who lived on the island of Rhodes, from where the ship carrying the Antikythera mechanism might have sailed: “If only ever brought to Scythia or Britain that ball (sphaera) that our friend Posidonius recently made, a ball whose individual revolutions reproduce what happens in the sky with the Sun, Moon and five planets on different days and nights, then who is in these barbaric countries would doubt that this ball is the product of perfect reason? (Cicero. On the nature of the gods, II, 34)
Further research showed that the Antikythera Mechanism was an astronomical and calendar calculator used to predict the positions of celestial bodies in the sky, and could also serve as a planetarium to demonstrate their movement. Thus, we are talking about a more complex and multifunctional device than the celestial globe of Archimedes.
According to one hypothesis, this device was created at the Academy, founded by the Stoic philosopher Posidonius on the Greek island of Rhodes, which at that time was known as the center of astronomy and "mechanical engineering". It is also speculated that the engineer who developed the device may have been the astronomer Hipparchus (c. 190-120 BC), who also lived on the island of Rhodes, since it contains a mechanism that uses his theory of the motion of the moon.
However, the latest findings of the Antikythera Mechanism Research Project participants, published on July 30, 2008 in the journal Nature, suggest that the concept of the mechanism originated in the colonies of Corinth, which may indicate a tradition going back to Archimedes.
Despite the poor preservation and fragmentation of the parts of the Antikythera mechanism, thanks to the painstaking work of researchers, it is possible to present with sufficient confidence in general terms its structure and functions.
After setting the date, the device was presumably operated by rotating a knob located on the side of the case. The large 4-spoke drive wheel was linked by multi-stage gears with multiple gears rotating at different speeds and moving the dials.
The movement had three main dials with concentric scales: one on the front and two on the back. There were two scales on the front panel: the fixed outer one, representing the ecliptic (a large circle of the celestial sphere along which the apparent annual movement of the Sun occurs), was divided into 360 degrees and 12 segments of 30 degrees with the signs of the Zodiac, and the movable inner one, which had 365 divisions by the number of days in the Egyptian calendar, which was used by Greek astronomers. The calendar error caused by the longer real duration of the solar year (365.2422 days) could be corrected by turning the calendar dial 1 division back every 4 years.
The front dial probably had three hand indicators: one with the date, and the other two with the positions of the Sun and Moon relative to the plane of the ecliptic. The moon's position indicator made it possible to take into account the unevenness of its motion caused by the fact that the Earth's satellite moves not in a circular but in an elliptical orbit. For this, an ingenious gear system was used, which included two gears with a center of gravity offset relative to the axis of rotation.
On the front panel there was also a mechanism with a moon phase indicator. A spherical model of the Moon, half silver plated, half black, was shown in a round window, showing the current phase of the moon.
There is a point of view that the mechanism could have pointers for all five planets known to the Greeks (these are Mercury, Venus, Mars, Jupiter and Saturn). But not a single transmission responsible for such planetary mechanisms has been found. At the same time, recently discovered inscriptions, which mention stationary points of planets, suggest that the Antikythera Mechanism could also describe their motion.
Finally, on a thin bronze plate covering the front dial, there was a parapegma - an astronomical calendar showing the rising and setting of individual stars and constellations, indicated by Greek letters corresponding to the same letters on the zodiacal scale.
Thus, the device could show the relative position of the luminaries on the celestial sphere on a specific date, which could have practical application in the work of astronomers and astrologers, eliminating complex and laborious calculations.
On the back were two large dials. The upper dial, which was in the form of a spiral with five turns and 47 branches in each turn, displayed the Metonic cycle, named after the Athenian astronomer and mathematician Meton, who proposed it in 433 BC. It was used to coordinate the duration of the lunar month and solar year in the lunisolar calendar.
As the ancient Greek scientist of the 1st century BC Gemini noted in his "Elements of Astronomy", the Greeks made sacrifices to the gods according to the customs of their ancestors, and therefore "they must maintain agreement with the Sun in years and with the Moon in days and months."
On the upper dial of the back panel there was also a sub-dial, divided into four sectors, reminiscent of the second dial of a modern wrist watch.
In 2008, the head of the Antikythera Mechanism Research Project Tony Freese and his colleagues found on this dial the names of 4 Panhellenic Games - Isthmian, Olympic, Nemean and Pythian, as well as the Games in Dodona. The Olympic dial had to be incorporated into an existing gear train that moved the pointer 1/4 turn per year.
This confirms that the Antikythera mechanism could be used to calculate the dates of religious holidays associated with astronomical events (including the Olympic and other sacred games), and also serve to correct calendars based on the Metonian cycle.
At the bottom of the back was a 223-compartment spiral dial showing the Saros cycle. Saros, possibly discovered by Babylonian astronomers, is a period after which, due to the repetition of the relative position of the Sun, the Moon and the nodes of the lunar orbit on the celestial sphere, solar and lunar eclipses are repeated in the same sequence. Saros includes 223 synodic months, which is approximately 18 years 11 days 8 hours.
On the scale of the dial showing the cycle of Saros, there are symbols Σ for lunar eclipses (ΣΕΛΗΝΗ, Moon), symbols Η for solar eclipses (ΗΛΙΟΣ, Sun) and numerals in Greek letters, presumably indicating the date and hour of the eclipses. It was possible to establish correlations with the actually observed eclipses.
The smaller subdial displays the "triple Saros" or "Exceligmos cycle" (Greek ἐξέλιγμος), giving the period of recurrence of eclipses in whole days. The field of this dial is divided into three sectors: one clean and two with hour markings (8 and 16), which must be added for every second and third Saros in the cycle to get the time of the eclipses. This confirms that the instrument could have been used to predict lunar and possibly solar eclipses.
Computer reconstruction of the mechanism
The Antikythera mechanism was enclosed in a wooden box, on the doors of which there were bronze tablets containing instructions for its use with astronomical, mechanical and geographical data. Interestingly, among the place names in the text, ΙΣΠΑΝΙΑ (Spain in Greek) occurs, which is the oldest mention of the country in this form, in contrast to Iberia.
Thanks to the efforts of researchers, the Antikythera Mechanism is gradually revealing its secrets, expanding our understanding of the possibilities of ancient science and technology. In 1974, in his article "Greek Gears - Calendar Computer BC", Price presented a theoretical model of the Antikythera Mechanism, based on which Australian scientist Allan George Bromley of the University of Sydney and watchmaker Frank Percival made the first working model. A few years later, the British planetarium inventor John Gleave designed a more accurate model that followed Price's scheme.
A major contribution to the study of the Antikythera Mechanism was made by Michael Wright, an employee of the London Science Museum and Imperial College London, who in 2002 was able to recreate a complete reconstruction of the device, and in 2007 presented a modified model. It turned out that the Antikyker mechanism makes it possible to simulate not only the movements of the Sun and the Moon, but also Mercury, Venus, Mars, Jupiter and Saturn.
In 2016, scientists presented the results of their many years of research. On the remaining 82 fragments of the device, it was possible to decipher 2,000 letters, including 500 words. Yet the description, according to scientists, could take 20,000 characters. They told about the purpose of the device, in particular, about determining the dates of 42 astronomical phenomena. In addition, the functions of prediction were laid in it, in particular, the color and size of the solar eclipse, and from it the strength of the winds at sea, were determined (the Greeks inherited this belief from the Babylonians).
"This device is just extraordinary, it is one of a kind," said Mike Edmunds, a professor at Cardiff University who is leading the research on the mechanism. "Its design is excellent and the astronomy is absolutely accurate … In terms of historical value, I consider this mechanism more expensive than the Mona Lisa."