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A team of researchers from University College London and the Science and Technology in Archeology and Culture Research Center at the Cyprus Institute have solved a major piece of the puzzle that makes up an ancient Greek astronomical calculator called the Antikythera Mechanism.
Computer model of the display of the Antikythera mechanism: in the center, the dome of the Earth, the phase of the Moon and its position in the zodiac – then rings for Mercury, Venus, true Sun, Mars, Jupiter, Saturn and Date , with ‘small sphere markers and smaller markers for oppositions. The scale marks and index letters of the synodic cycles of the planets are inscribed on the planetary rings. Around these, the zodiac and the Egyptian calendar. The real sun ring has a “little golden sphere” with a “pointer”. When the Moon and Sun pointers coincide, the Moon sphere is black for the New Moon; when the pointers are on opposite sides, the Moon sphere is white for the Full Moon. The head of the dragon’s hand shows the ascending lunar knot; the tail the descending knot. Small triangles on the actual solar ring near the pointer show wider and narrower eclipse boundaries. Eclipses are possible if the dragon’s hand is within these limits. When the Moon pointer is in front of the Dragon Head, the Moon is south of the node; after that, it is north of the node – the reverse for the descending node. A date pointer is attached to a narrow date ring, indicating the date in the Egyptian calendar. Image Credit: Freeth et al., doi: 10.1038 / s41598-021-84310-w.
In 1900, a team of Greek sponge divers discovered a 2,050-year-old Roman wreck off the remote island of Antikythera in Greece.
It is believed that the ship was carrying looted treasures from the coast of Asia Minor to Rome, to support a planned triumphal parade for Julius Caesar.
Divers recovered a rich collection of ancient artifacts from the wreck site, including bronze and marble statues, jewelry, furniture, luxury glassware, and a surprisingly complex device now known as the Antikythera mechanism.
Built between 150 and 100 BCE, it was a mechanical computer with bronze gears that used revolutionary technology to make astronomical predictions, mechanizing astronomical cycles and theories.
“He calculated the ecliptic longitudes of the Moon, the Sun and the planets; the phase of the Moon; the age of the moon; the synodic phases of the planets; days excluded from the Metonic Calendar; eclipses – possibilities, time, characteristics, years and seasons; the helical climbs and the backdrops of prominent stars and constellations; and the cycle of the Olympiad – an ancient Greek astronomical collection of astounding ambition, ”said Tony Freeth, professor at University College London, and his colleagues.
Now divided into 82 fragments, only a third of the original survives, including 30 corroded bronze pinions.
Nonetheless, they are rich in millimeter-level evidence – with fine detail of mechanical components and thousands of tiny characters of text, buried within the fragments and unread for over 2,000 years.
The largest surviving fragment, Fragment A, exhibits characteristics of bearings, pillars and a block. Another, Fragment D, features an unexplained disc, a 63-tooth gear, and a plate.
In previous research, scientists have revealed thousands of text characters hidden inside the fragments using microfocus X-ray computed tomography.
The inscriptions on the back cover include a description of the display of the cosmos, the planets moving on rings and indicated by marker beads.
It is this exhibit that Professor Freeth and his co-authors have worked to piece together.
Inscriptions on the Antikythera Mechanism. (a) FRONT COVER: Planetary cycles, framed by molding from Fragment 3. FRONT PLATE: Parapegma, above and below the Cosmos display, indexed on the zodiac dial. BACK PLATE: Names of the months on the Metonic calendar. Features Eclipse, round Metonic calendar and Saros Eclipse prediction dials – indexed to the latter. Eclipse glyphs indexed on the Saros dial. BACK COVER: User manual including description of Cosmos, calendar structure and Moon-Sun cycles. (b) Inscription on the front cover (FCI): composite X-ray computed tomography of fragments G, 26 and 29 and other small fragments. The FCI describes the synodic cycles of the planets and is divided into regions for each planet in customary cosmological order (CCO). The numbers ΨΞΒ (462) in the Venus section and ΨMΒ (442) in the Saturn section are highlighted. (c) Back Cover Inscription (BCI): Composite X-ray CT of Fragments A and B. A User Manual: the top is a description of the front cosmos display with the planets in the CCO; in red are the names of the planets as well as the word KOΣMOY – “of the Cosmos”. Image Credit: Freeth et al., doi: 10.1038 / s41598-021-84310-w.
“Ours is the first model that meets all physical evidence and matches the descriptions of the scientific inscriptions carved into the mechanism itself,” Professor Freeth said.
“The Sun, the Moon and the planets are displayed in an awe-inspiring tour de force of ancient Greek brilliance.”
Two critical numbers in the X-ray front cover of the Mechanism, 462 years and 442 years, accurately represent the cycles of Venus and Saturn respectively.
When observed from Earth, the cycles of the planets sometimes reverse their movements against the stars.
Astronomers must follow these varying cycles over long periods of time in order to predict their positions.
“Classical astronomy of the first millennium BC originated in Babylon, but nothing in this astronomy suggested how the ancient Greeks found the cycle very precise of 462 years for Venus and 442 years for Saturn,” he said. said Aris Dacanalis, holder of a doctorate. . candidate in the Department of Mechanical Engineering at University College London.
Using an ancient Greek mathematical method described by the philosopher Parmenides, the team not only explained how the cycles of Venus and Saturn were derived, but also managed to recover the cycles of all the other planets, where evidence was lacking.
“After a considerable struggle, we were able to match the evidence for fragments A and D to a mechanism for Venus, which models exactly its 462-year planetary period relationship, with the 63-tooth gear playing a crucial role,” said David Higgon, a PhD candidate in the Department of Mechanical Engineering at University College London.
“We then created innovative mechanisms for all planets that would calculate new advanced astronomical cycles and minimize the number of gears in the entire system, so that they fit into the tight spaces available,” said the Professor Freeth.
“This is a key theoretical breakthrough in how the Cosmos was constructed in the Mechanism,” said Dr Adam Wojcik, also from the Department of Mechanical Engineering at University College London.
“Now we have to prove its feasibility by making it with old techniques. A particular challenge will be the interlocking tube system that carried the astronomical outputs. “
The team’s results were published in the journal Scientific reports.
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T. Freeth et al. 2021. A model of the cosmos in the ancient Greek Antikythera mechanism. Sci representative 11 5821; doi: 10.1038 / s41598-021-84310-w
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