Antikythera Mechanism
An ancient Greek orrery that predicts eclipses and tracks the Olympic cycle.
The Antikythera Mechanism, the oldest known example of an analogue computer, is a hand-powered orrery built in the 2nd century BC; Indiana Jones and the Dial of Destiny turns it into Archimedes' Dial, a device built by Archimedes that reveals time fissures. Discovered in 1901 within the wreckage of a Roman cargo ship off the island of Antikythera, this artifact was initially overlooked until politician Spyridon Stais noticed a gear embedded in a corroded lump in 1902. It was found as one lump, later separated into three main fragments, which conservation has divided into 82 fragments, four of them containing gears. It was designed to predict astronomical positions and eclipses decades in advance, as well as track the four-year cycle of athletic games similar to an Olympiad.
Quick Facts
- Writing
- Ancient Greek
- Discovered place
- Antikythera, Greece
- Discovered date
- 1901
- Location
- National Archaeological Museum, Athens
- Created
- 2nd century BC
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. In 2005, a team led by Mike Edmunds used computer X-ray tomography; the scans suggest that the mechanism had 35 meshing bronze gears, 30 of which are still visible. 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.
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 largest gear originally had 223 teeth and measures about 13 cm (5 in) in diameter.
- Machines with similar complexity did not reappear until the 14th century, over 1,000 years later.
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