The Antikythera Mechanism
Oldest known analogue computer, predicting astronomical events and Olympic cycles.
The Antikythera mechanism is the oldest known example of an analogue computer. It is an ancient Greek hand-powered orrery, or model of the Solar System, built in the 2nd century BC and discovered in 1901. The device could predict astronomical positions and eclipses decades in advance and also track the four-year cycle of athletic games similar to an olympiad, such as the ancient Olympic Games. The artefact was recovered from a Roman cargo shipwreck off the coast of the Greek island Antikythera in 1901. It was initially overlooked until May 1902, when Greek politician Spyridon Stais noticed a gear embedded in a fragment during a visit to the National Archaeological Museum in Athens. His cousin, museum director Valerios Stais, conducted the first study. The mechanism was found as a single lump, later separated into three main fragments, which after conservation now comprise 82 separate fragments. Four of these contain gears, while inscriptions appear on many others. The largest gear originally had 223 teeth and is about a certain diameter. All fragments are housed at the National Archaeological Museum, alongside reconstructions. In 2005, a team from Cardiff University led by Mike Edmunds used computer X-ray tomography and high-resolution scanning to image inside the crust-encased fragments and read faint inscriptions. These scans revealed 35 meshing bronze gears, 30 still visible, enabling it to follow the Moon and Sun through the zodiac, predict eclipses, and model the Moon’s irregular orbit. This lunar motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, who may have been consulted. Inscriptions deciphered in 2016 revealed numbers connected with the synodic cycles of Venus and Saturn. The mechanism is believed to have been designed by Hellenistic scientists and dated to around 87 BC, between 150 and 100 BC, or 205 BC. It must have been built before the shipwreck, dated to approximately 70–60 BC. In 2022, researchers proposed an initial calibration date of 23 December 178 BC, while others suggest 204 BC. Machines of similar complexity did not reappear until the 14th century in western Europe.
- Number of known gears
- 30 meshing bronze gears (with possible debate about a 31st or 32nd)
Verified Timeline
Quick Facts
- Writing
- Ancient Greek
- Discovered Place
- Antikythera, Greece
- Discovered Date
- 1901
- Location
- National Archaeological Museum, Athens
- Period
- Hellenistic
- Created
- 2nd century BC
Facts from the source article.
Lore & Background
The Antikythera Mechanism was originally a single, corroded lump of bronze and wood, retrieved from a Roman-era shipwreck off the Greek island of Antikythera in 1901. After conservation, it was separated into three main fragments, which were further divided into 82 separate pieces. Four of these fragments contain gears, and many others bear inscriptions. The largest surviving gear measures about 13 centimeters in diameter and originally had 223 teeth. The device was housed in a wooden-framed case of uncertain overall size. It is the oldest known analogue computer, a hand-powered orrery built in the 2nd century BC. It could predict astronomical positions and eclipses decades in advance and track the four-year cycle of athletic games similar to the ancient Olympic Games. Modern X-ray tomography and high-resolution scanning have revealed 35 meshing bronze gears, 30 of which are still visible. This gearwork allowed it to follow the Sun and Moon through the zodiac, model the Moon’s irregular orbit (where its velocity is higher at perigee than apogee), and predict eclipses. Inscriptions deciphered in 2016 revealed numbers connected with the synodic cycles of Venus and Saturn, suggesting a missing portion may have calculated the positions of the five classical planets. The mechanism is believed to have been designed by Hellenistic scientists and constructed before the shipwreck, which has been dated to approximately 70–60 BC. Its complexity was not matched again in Western Europe until the 14th century. All fragments are kept at the National Archaeological Museum in Athens, alongside reconstructions.
Reader's Guide
The Antikythera mechanism represents a pinnacle of Hellenistic engineering and astronomical knowledge. Its complexity—with 35 meshing bronze gears enabling predictions of lunar and solar positions, eclipses, and the Moon's irregular orbit—was unmatched until the 14th century in western Europe. The device's construction relied on theories of Hipparchus of Rhodes, and its calendar on the Metonic Spiral suggests origins in Corinth or its colonies. The mechanism's discovery revolutionized understanding of ancient technology, demonstrating that sophisticated analogue computing existed over 2,000 years ago.
Did You Know?
- The mechanism could track the four-year cycle of athletic games similar to the ancient Olympic Games.
- The mechanism was not treated upon removal from seawater, resulting in deformational changes.
Frequently Asked Questions
What is The Antikythera Mechanism?
It is a hand-cranked bronze device from ancient Greece that modeled the movements of the Sun, Moon, and planets. Built sometime in the 2nd century BC, it stands as the earliest known analogue computer ever recovered.
What could The Antikythera Mechanism actually predict?
Its network of 35 meshing bronze gears let a user forecast the positions of celestial bodies and solar or lunar eclipses years in advance. It also tracked the four-year cycle of Greek athletic competitions, working much like a mechanical almanac.
Why is The Antikythera Mechanism considered so important to the history of science?
It predates any other known geared computing device by roughly a millennium, proving that Hellenistic engineers had already mastered analog computation. Its existence fundamentally reshaped what scholars assumed ancient Greek science was capable of.
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