Stars and beyond
The Antikythera Mechanism of Ancient Greece has puzzled academics for more than a century after it was rescued from the bed of the Mediterranean, where it had lain since about 70BC amid the remains of a shipwreck.
New analysis of the 82 fragments of the bronze mechanism reveal that it was more sophisticated and ancient than suspected.
Researchers have established that it was able to predict eclipses and track the paths of the Sun and the Moon through the zodiac, and probably even showed ancient astronomers the movements of the five known planets.
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The mechanism, which is formed mainly of gears and pointers, was so precise that it was even able to take into account the moon’s elliptic motion, first identified by Hipparchos in the 2nd century BC.
Surface imaging and high- resolution X-ray tomography were used to determine the original shapes of the remains and to identify inscriptions.
Once the researchers knew the measurements and shapes of the surviving pieces, they were able to work out how they all fitted together, a process complicated by some important parts being missing.
Mike Edmunds, of Cardiff University, said: “This device is just extraordinary, the only thing of its kind. The design is beautiful, the astronomy is exactly right. The way the mechanics are designed just makes your jaw drop. Whoever has done this has done it extremely well.
“It does raise the question: what else were they making at the time? In terms of historic and scarcity value, I have to regard this mechanism as being more valuable than the Mona Lisa.”
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The virtual reconstruction, reported in the journal Nature, shows that the device had 37 gear wheels, seven of which had to be hypothesised.
Until now the best estimate of the number of gears involved in the calculator was 31, a figure proposed by Professor Derek De Solla Price, a British scientist who spent much of his career from the 1950s to the 1970s trying to understand the machinery. He identified 29 gears and hypothesised two more.
François Charette, an academic in Munich, said of the new interpretation of the mechanism: “The new model is highly seductive and convincing in all of its details. It ought to force us, definitively, to abandon Price’s reconstruction, which is still frequently reproduced in general and scholarly books.”
The British-Greek research team was able to double the number of deciphered inscriptions, which gave them new clues to the purpose of the Antikythera Mechanism.
Among the inscriptions were references to planetary movements which convinced the researchers that, as well as understanding the movements of the Sun and the Moon, the Ancient Greeks were able to predict the positions of the five known planets in relation to the stars.
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The remains of the corroded device were discovered inside a broken bronze and wooden case in 1901 by sponge divers exploring a shipwreck off the island of Antikythera, between Crete and the Peloponnese. It was 42m (138ft) below the surface. The ship was Roman but the cargo was Greek.
Because the ship is thought to have sailed from Rhodes, where Hipparchos was living, the researchers suggest that he may have had a role in constructing the device.
The findings of the study will be announced today at a conference in Athens, where the remains of the device are stored.