The Antikythera Mechanism (c. 150–100 BC)
An ancient Greek geared astronomical calculator recovered from a shipwreck off the island of Antikythera, whose bronze gearing predicted celestial movements and eclipse cycles more than a thousand years before anything comparable is known to have existed.
Events
The Wreck Discovered
Sponge divers sheltering from a storm near the small island of Antikythera between Crete and the Greek mainland discovered a Roman-era shipwreck lying about 45 meters (150 feet) deep. Diver Elias Stadiatis reported a heap of decaying corpses and statues; salvage operations with the Greek navy followed, recovering bronze and marble sculptures, glassware, jewelry, and other cargo over the following months.
Location: Off Antikythera island, Greece
A Gear Wheel in a Corroded Lump
Museum curator Valerios Stais noticed a gear wheel embedded in a corroded lump of bronze recovered from the wreck, fragments of what would become known as the Antikythera mechanism. The object confounded expectations of ancient technology; some early commentators doubted it could be as old as the wreck itself, a debate that would take decades of study to resolve.
Location: National Archaeological Museum, Athens, Greece
Derek de Solla Price Deciphers the Gearing
Historian of science Derek de Solla Price, working from radiographs of the fragments, published Gears from the Greeks, reconstructing the mechanism's gear trains and arguing it was a geared astronomical calculator of the second century BC. Price's analysis established that ancient Greek craftsmen had built precision bronze gearing of a sophistication previously attributed only to medieval Europe.
Location: Yale University, United States
The CT Scans and Hidden Inscriptions
Microfocus X-ray computed tomography and high-resolution imaging of the 82 surviving fragments, organized through the National Archaeological Museum with X-Tek Systems, revealed text hidden inside the corroded pieces. The inscriptions included a user's manual describing the dials, and a paper in Nature reported the readings, transforming the study of the device from gear geometry into a text-based reconstruction.
Location: Athens, Greece
The Calendar of the Cosmos Display
Studies of the imaging data established the functions of the main dials: the front displayed the positions of the Sun and Moon, and possibly the five planets known in antiquity, against the zodiac; the back tracked the 19-year Metonic calendar cycle, the 223-month Saros cycle used to predict eclipses, and a four-year cycle of Greek athletic games including the Olympiads. The mechanism was thus a portable astronomical and calendrical computer, dated by its inscriptions to roughly 150-100 BC.
Location: Cardiff, Wales, United Kingdom
Return to the Wreck
New archaeological expeditions returned to the shipwreck site, applying modern methods to an area first stripped a century earlier. The project recovered additional finds, including a human skeleton in 2016, bronze fittings, and a disc-shaped object carrying a bull image that excavators compared stylistically to the mechanism's components, continuing to add context to the ship and its cargo.
Location: Antikythera island, Greece
A Model of the Cosmos
Researchers at University College London published a mechanical solution in Scientific Reports for the gearing of the mechanism's front cosmos display, reconciling the physical fragments with the inscriptions and astronomical period relations described by ancient sources. The work showed how the device could have displayed the wandering motions of the planets with the technology available to Greek craftsmen of the second century BC.
Location: London, United Kingdom