Scientists solve another part of the puzzling Antikythera mechanism

Scientists have long struggled to solve the puzzle of the gear system at the front of the so-called Antikythera Mechanism – a fragmentary ancient Greek astronomical calculator, possibly the earliest example of a geared device. Now, an interdisciplinary team from University College London (UCL) has developed a computational model that reveals a dazzling exposure of the ancient Greek cosmos, according to a new article published in the journal Scientific Reports. The team are currently building a replica mechanism, moving gears and all, using modern machinery. You can watch a full 11 minute video about the project here (integration currently disabled).

“Ours is the first model that meets all physical evidence and matches the descriptions of the scientific inscriptions carved into the mechanism itself,” said lead author Tony Freeth, mechanical engineer at UCL. “The Sun, the Moon and the planets are displayed in an impressive tour de force of ancient Greek brilliance. “

“We believe our reconstruction matches all the evidence scientists have gleaned from the remains that exist to date,” co-author Adam Wojcik, a materials scientist at UCL, told The Guardian.

The manual Antikythera mechanism has a long history. In 1900, a Greek sponge diver named Elias Stadiatis discovered the wreckage of an ancient cargo ship off the island of Antikythera in Greece. He and other divers recovered all kinds of artifacts from the ship. A year later, an archaeologist named Valerios Stais was studying what he thought was just a piece of rock recovered from the shipwreck, but noticed that there was a cogwheel embedded in it. 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 the size of a shoebox, with dials on the outside, containing an intricate assembly of cogwheels inside. The larger piece is known as Fragment A, which features bearings, pillars, and a block. Another piece, Fragment D, has a disc, a 63-tooth gear, and a plate. The very existence of the mechanism offers strong evidence that such technology existed as early as 150-100 BC, but knowledge was subsequently lost. Similar machines of equivalent complexity did not reappear until the 18th century. Although it was found on a Roman freighter, historians believe it is of Greek origin, possibly from the island of Rhodes, 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 to study the theoretical workings of the device. Based on x-ray and gamma-ray photographs of the fragments, Price and physicist Charalampos Karakalos published a 70-page article in 1959 in the Transactions of the American Philosophical Society.. Based on these images, Price hypothesized that the mechanism was used to calculate the motions of stars and planets, making it the first known analog computer.

In 2002, Michael Wright, then curator of mechanical engineering at the Science Museum in London, made headlines with new, more detailed x-ray images of the device taken by linear tomography – meaning that only the features of a plane particular are tuned, allowing a closer inspection and the exact location of each gear. Wright’s closer analysis revealed a fixed central gear in the mechanism’s main wheel, around which other moving gears could rotate. He concluded that the device was specifically designed to model “epicyclic” motion, in keeping with the ancient Greek notion that celestial bodies moved in circular patterns called epicycles. (The fixed point around which they moved was generally considered the Earth, until Copernicus realized that it was in fact the Sun.)