A team of researchers from University College London and the Cyprus Institute’s Scientific and Technological Center for Archeology and Culture solved a large part of the puzzle that made up an ancient Greek astronomical calculator called the Antikythera Mechanism.
Computer model of the screen of the Antikythera mechanism: in the center, the dome of the earth, the phase of the moon and its position in the zodiac – then reads Mercury, Venus, true Sun, Mars, Jupiter, Saturn and Date, with ‘small sphere markers and smaller markers for oppositions. Scale marks and index letters for the synodic cycles of the planets are inscribed on the planetary rings. Around this, the Zodiac and the Egyptian calendar. The real Sun-ring has a ‘golden sphere’ with ‘indicator’. When the lunar and solar hands coincide, the lunar sphere appears black for the new moon; if the direction indicators are on either side, the lunar sphere appears white for the full moon. The head of the dragon’s hand shows the rising moon knot; the tail the descending knot. Small triangles on the true sundial, near the pointer, show wider and narrower eclipse limits. Eclipses are possible if the dragon hand is within these limits. When the moon is in front of the dragon’s head, the moon is south of the node; thereafter it is north of the knot – reverse for the descending knot. 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 2050-year-old Roman shipwreck on the remote island of Antikythera in Greece.
It is suspected that the ship was transporting looted treasures from the coast of Asia Minor to Rome to plan a triumphal procession planned for Julius Caesar.
The divers found a rich collection of antique artifacts from the wreck site, including bronze and marble statues, jewelry, furniture, luxury glassware and a surprisingly intricate device currently known as Antikythera Mechanism.
The construction between 150 and 100 BC was a mechanical computer of bronze gears that used cutting-edge technology to make astronomical predictions by mechanizing astronomical cycles and theories.
“It calculates the ecliptic longitudes of the Moon, Sun and planets; the phase of the Moon; the era of the moon; the synodic phases of the planets; the excluded days of the Metonic calendar; eclipses – possibilities, times, characteristics, years and seasons; the heliacal rises and settings of prominent stars and constellations; and the Olympics cycle – an ancient Greek astronomical compendium of staggering ambition, ”said Professor Tony Freeth and colleagues from University College London.
Now divided into 82 fragments, only a third of the original survived, including 30 corroded bronze gears.
Nevertheless, they are rich in evidence at the millimeter level – with fine details of mechanical components and thousands of small text characters, buried in the fragments and unread for more than 2000 years.
The largest surviving fragment, Fragment A, displays features of bearings, pillars and a block. Another, Fragment D, contains an unexplained disc, 63-speed gear and plate.
In previous research, scientists uncovered thousands of text characters hidden in the fragments using microfocus X-ray computed tomography.
Inscriptions on the back cover contain a description of the cosmos exhibit, with the planets moving on rings and indicated by marking beads.
It is this performance that Professor Freeth and co-authors worked to reconstruct.
Inscriptions on the Antikythera mechanism. (a) COVER: Planet cycles, framed by shape from Fragment 3. COVER: Parapegma, above and below the Cosmos Display, indexed to the Zodiac Dial. BACK PLATE: Month names on the Metonic Calendar. Eclipse features, round metonic calendar and Saros Eclipse Prediction Dials – indexed on the latter. Eclipse slips indexed by the Saros Dial. BACK: User manual, including description of the Cosmos, calendar structure and lunar-solar cycles. (b) Cover heading (FCI): composite X-ray CT of fragments G, 26 and 29 and other small fragments. The FCI describes synodic cycles of the planets and is divided into regions for each planet in the usual cosmological order (CCO). The numbers ΨΞΒ (462) in the Venus section and ΨMΒ (442) in the Saturn section are highlighted. (c) Inscription on the back cover (BCI): composite X-ray CT from fragments A and B. A user manual: the upper part is a description of the leading Cosmos screen with planets in the CCO; in red are the planet names 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 matches all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the Mechanism itself,” Professor Freeth said.
“The sun, the moon and the planets are displayed in an impressive tour of the ancient Greek splendor.”
Two critical numbers in the X-rays of the cover of the Mechanism, of 462 years and 442 years, accurately represent cycles of Venus and Saturn, respectively.
When observed from Earth, the planets’ motions sometimes reverse against the stars.
Astronomers must follow these variable cycles over long periods of time to predict their positions.
“The classical astronomy of the first millennium BC originated in Babylon, but nothing in this astronomy suggested how the ancient Greeks found the highly accurate 462-year cycle for Venus and 442-year cycle for Saturn,” said Aris Dacanalis , a doctor said. . 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 for Venus and Saturn were derived, but also succeeded in restoring the cycles of all the other planets, where the evidence is missing.
“After considerable difficulty, we were able to adapt the evidence in fragments A and D to a mechanism for Venus, which modeled exactly the 462-year-old planetary relationship, with the 63-tooth gear playing a crucial role,” has David Higgon, a Ph.D. candidate in the Department of Mechanical Engineering at University College London.
“We then created innovative mechanisms for all the planets that would calculate the new advanced astronomical cycles and reduce the number of gears in the entire system so that it would be available in the limited spaces,” Professor Freeth said.
“This is an important theoretical advance on how the cosmos is built into the mechanism,” said dr. Adam Wojcik, also from the Department of Mechanical Engineering at University College London, said.
‘Now we have to prove its feasibility by making it with ancient techniques. A particular challenge is the system of nested tubes that carry 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. Scientific Rep 11, 5821; doi: 10.1038 / s41598-021-84310-w