Antikythera Mechanism

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Lore & Background

Retrieved from a depth of 45 metres off Point Glyphadia by Captain Dimitrios Kontos and sponge divers in early 1900, the mechanism appeared as a single encrusted piece before fracturing into three major fragments. By 2005, a team led by Mike Edmunds used computer X-ray tomography to reveal that the device originally contained 37 meshing bronze gears. These gears enabled it to follow the movements of the Moon and Sun through the zodiac and model the irregular orbit of the Moon, where velocity is higher at perigee than apogee—a motion studied by astronomer Hipparchus of Rhodes in the 2nd century BC. Inscriptions deciphered in 2016 connected numbers to the synodic cycles of Venus and Saturn, while speculation suggests a missing portion may have calculated the positions of the five classical planets.

In Their Own Story

The mechanism's origins are linked to Hellenistic scientists, with theories pointing to Corinthian colonies or the school of Archimedes in Syracuse. In 2014, researchers proposed an initial calibration date of 23 December 178 BC, while other experts suggest 204 BC as a more likely date. The device must have been constructed before the shipwreck, which multiple lines of evidence date to approximately 70–60 BC. Fragments were found to contain inscriptions describing functions like the Callippic cycle, with Fragment 19 specifically referencing '... 76 years ...'. Although machines of similar complexity did not appear again until the 14th century in western Europe, such as those by Richard of Wallingford and Giovanni de' Dondi, the Antikythera Mechanism remains a singular achievement. It was found as one lump, later separated into 82 fragments, with the largest gear measuring about 13 cm in diameter and originally possessing 223 teeth.

Reader's Guide

To understand the mechanism's operation, one must examine its 82 known fragments, seven of which are mechanically significant. The device utilized a four-year cycle to track athletic games, functioning as an analog computer for astronomical predictions. Researchers have determined that the calendar on the Metonic Spiral is of the Corinthian type, though not specifically Syracuse. The mechanism's design relied on theories developed by Greek astronomers in the second century BC, potentially involving Hipparchus of Rhodes, who was active from about 140–120 BC. The astronomical events recorded on its Parapegma align best with latitudes between 33.3 and 37.0 degrees north, matching the location of Rhodes. Conservation efforts have preserved these fragments at the National Archaeological Museum in Athens, where reconstructions demonstrate how it may have looked and worked.

Did You Know?

• The mechanism was discovered as a single lump of corroded bronze and wood in 1901 but is now divided into 82 separate fragments.
• The largest gear originally had 223 teeth and measures about 13 cm (5 in) in diameter.
• It could predict astronomical positions and eclipses decades in advance using 37 meshing bronze gears.
• The device was used to track the four-year cycle of athletic games similar to an Olympiad.
• Machines with similar complexity did not reappear until the 14th century, over 1,000 years later.