Scientists solve another piece of the puzzling Antikythera mechanism

On May 17, 1902, Greek archaeologist Valerios Stais discovered the Antikythera mechanism, an ancient mechanical analog computer. A short excerpt from the article:

"The 82 surviving fragments of the device were originally housed in a wooden box roughly the size of a shoebox, with dials on the outside, containing a complex assembly of gear wheels within. The largest piece is known as Fragment A, which has bearings, pillars, and a block. Another piece, Fragment D, has a disk, a 63-tooth gear, and plate. The mechanism's very existence offers strong evidence that such technology existed as early as 150-100 BC, but the knowledge was subsequently lost. Similar machines with equivalent complexity didn't appear again until the 18th century. While it was found on a Roman cargo ship, historians believe it is Greek in origin, possibly from the island of Rhodes, which was known for impressive displays of mechanical engineering.

It took decades just to clean the device off, and in 1951, a British science historian named Derek J. de Solla Price began investigating 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 paper in 1959 in the Transactions of the American Philosophical Society. 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 curator of mechanical engineering at the Science Museum in London, made headlines with new, more detailed X-ray images of the device taken via linear tomography—which means that only features in a particular plane come into focus, enabling closer inspection and pinning 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. (This was pre-Copernicus, so the fixed point around which they moved was believed to be the Earth.)"

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