Tony Freeth
Scientists have long struggled to solve the gear system puzzle on the front of the so-called Antikythera mechanism – a fragmentary ancient Greek astronomical calculator, perhaps the earliest example of a gear mechanism. Now, an interdisciplinary team from University College London (UCL) has come up with a computer model that reveals a dazzling representation of the ancient Greek cosmos, according to a new article published in the journal Scientific Reports. The team is currently building a replica mechanism, moving gears and everything, using modern machines. You can watch an in-depth 11-minute video about the project here (embedding currently disabled).
“Ours is the first model to fit all of the physical evidence and match the descriptions in the scientific inscriptions engraved on the mechanism itself,” said lead author Tony Freeth, a mechanical engineer at UCL. “The sun, moon and planets are displayed in an impressive way tour de force of ancient Greek genius. “
“We believe our reconstruction fits with all the evidence scientists have collected from the extant remains to date,” study co-author Adam Wojcik, a materials scientist at UCL, told The Guardian.
The hand-operated Antikythera mechanism has a long history. In 1900, a Greek sponge diver named Elias Stadiatis discovered the wreck of an old cargo ship off the coast of Antikythera Island in Greece. He and other divers recovered all kinds of artifacts from the ship. A year later, an archaeologist named Valerios Stais studied what he thought was just a piece of rock recovered from the shipwreck, but he saw that there was a gear inside. It turned out to be an old mechanical device. The Antikythera Mechanism is now housed in the National Archaeological Museum of Athens.
The 82 surviving fragments of the device were originally housed in a wooden box about the size of a shoebox, with dials on the outside, containing a complex set of gears. The largest piece is known as fragment A, which has bearings, pillars and a block. Another piece, fragment D, has a disk, a gear with 63 teeth and a plate. The existence of the mechanism provides strong evidence that such technology existed as far back as 150-100 BC, but the knowledge was subsequently lost. Similar machines of equivalent complexity did not appear again until the 18th century. Although it was found on a Roman cargo ship, historians believe it to be of Greek origin, possibly from the island of Rhodes, which was known for its impressive displays of mechanical engineering.
It took decades to clean the device, and in 1951 a British science historian named Derek J. de Solla Price began researching the theoretical workings of the device. Based on X-ray and gamma photos of the fragments, Price and physicist Charalampos Karakalos published a 70-page article in the Transactions of the American Philosophical Society in 1959 Based on those images, Price hypothesized that the mechanism had been used to calculate the motions of stars and planets, making it the first known analog computer.
In 2002, Michael Wright, then conservator of mechanical engineering at the Science Museum in London, made headlines with new, more detailed X-rays of the device, taken via linear tomography – meaning only features in a particular plane come into view, allowing for closer inspection. possible and the exact location of each gear can be locked. Wright’s closer analysis revealed a fixed central gear in the main gear of the mechanism, around which other moving gears could turn. He concluded that the device was specifically designed to model “epicyclic” motion, in accordance with the ancient Greek idea that celestial objects moved in circular patterns called epicycles. (It was generally believed that the fixed point around which they moved was the Earth, until Copernicus realized it was, in fact, the sun.)