The Corroded Box That Held the Cosmos

In early 1900, Captain Dimitrios Kontos and a crew of sponge divers from the island of Symi came upon a wreck lying 45 metres deep off Point Glyphadia, near the small Greek island of Antikythera. Over the following two years, expeditions with the Hellenic Royal Navy hauled up bronze and marble statues, pottery, glassware, jewellery, and coins from the sunken Roman cargo ship. Among the treasures was an unremarkable-looking lump of corroded bronze and wood, retrieved in 1901, probably in July.

For two years it sat ignored at the National Archaeological Museum in Athens while staff focused on the more obviously dazzling statues. The seawater had already begun its damage: the bronze had turned into atacamite, a mineral that cracked and shrank as the piece dried, distorting its original shape. Then, on 17 May 1902, archaeologist Valerios Stais — prompted by his cousin, the politician Spyridon Stais, during a museum visit — noticed a gear wheel embedded in one of the rock-like fragments.

Stais suspected it was some kind of astronomical clock, but most scholars dismissed the idea as impossible for the era — the device seemed far too advanced to have been built alongside the other Hellenistic-era finds. German philologist Albert Rehm took the idea seriously, becoming the first to argue it was an astronomical calculator. But real momentum did not arrive until 1951, when British science historian Derek J. de Solla Price, of Yale University, began studying it in earnest.

In 1971, Price and Greek nuclear physicist Charalampos Karakalos used X-ray and gamma-ray imaging on the 82 surviving fragments, publishing their findings in 1974. Decades later, in 2005, a Cardiff University team led by Mike Edmunds applied computer X-ray tomography and high-resolution scanning, revealing faint inscriptions on the crust-encased casing and an astonishing internal structure: 37 meshing bronze gears.

Those gears let the mechanism track the Moon and Sun through the zodiac, predict eclipses, and model the Moon's irregular orbit — moving faster at perigee than at apogee, a phenomenon studied by the 2nd-century-BC astronomer Hipparchus of Rhodes, who may even have advised on the device's construction. Some researchers suspect a missing portion once calculated the positions of the five classical planets; inscriptions deciphered in 2016 revealed numbers tied to the synodic cycles of Venus and Saturn.