The Antikythera Mechanism
Sponge divers found a Greek shipwreck off Antikythera in 1900, and among its treasures was a corroded geared device. Decades of X-ray and statistical work show it was a hand-driven model of the heavens.
9 established, 3 disputed, 1 debunked, 1 unresolved. We do not pick an answer; the evidence places each claim. How we decide
46 citations from 6 independent sources - 40 echo the same voices and count once. Graded A1-C1.
Added 3 Jul 2026 - updated 29 Sept 2026
What the four states mean
- Establishedsupported, uncontested
- Disputedcredible sources disagree
- Debunkedrefuted by the evidence
- Unresolvedno settled answer
Established 9supported, uncontested
Sponge divers found the wreck near Antikythera, and by early 1901 divers were recovering its goods. Only a third of the mechanism survives, in 82 fragments, and the ship probably sank around 65 BC.▰▰▰▱▱ likely5 points
Supports- By chance, they found a wreck full of ancient Greek treasures, triggering the first major underwater archaeology operation in history.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- Overseen by a gunboat from the Greek navy to deter looters, by early 1901 the divers had begun to recover a wonderful array of ancient Greek goodsTony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- Today, only a third of the original Mechanism survives, split into 82 fragmentsTony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- The ship probably sank in around 65 BCTony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- Discovered by Greek sponge divers in 1900, the site yielded a wealth of artifactsAntikythera Shipwreck (Woods Hole Oceanographic Institution) analysis
Thirty gears survive, and the handle-driven mechanism calculated and displayed celestial cycles such as the phases of the Moon and a luni-solar calendar.▰▰▱▱▱ likely3 points
Supports- These enabled the identification of 30 surviving gears: 27 in Fragment A and one in each of Fragments B, C, and D.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- It is turned by the input handle and rotates once a year, thereby setting all the other gears in motion.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- It is known that it calculated and displayed celestial information, particularly cycles such as the phases of the moon and a luni-solar calendar.Freeth et al., 'Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism', Nature 444 (2006), abstract authoritative
The gearing contains a mechanical realization of Hipparchos's theory of the irregularities of the Moon's motion across the sky.▰▰▱▱▱ likely2 points
Supports- In the second century bc, Hipparchos developed a theory to explain the irregularities of the Moon's motion across the sky caused by its elliptic orbit. We find a mechanical realization of this theory in the gearing of the mechanismFreeth et al., 'Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism', Nature 444 (2006), abstract authoritative
- Wright had made an acute observation about how two of the epicyclic gears could interact to represent variable motion. Ultimately, he discarded this observation because it did not fit into his model, but I realised that this device could model the movement of the Moon.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
The lower back dial is a Saros eclipse-prediction dial, a four-turn spiral of 223 lunar months, whose glyphs describe the type and time of predicted eclipses.▰▰▱▱▱ likely2 points
Supports- The lower back dial is a Saros eclipse-prediction dial, arranged as a four-turn spiral of 223 lunar months, with glyphs indicating eclipse predictions.Freeth, Jones, Steele & Bitsakis, 'Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism', Nature 454 (2008), abstract authoritative
- Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions.Freeth, 'Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism', PLOS ONE (2014) authoritative
An upper subsidiary dial follows the four-year cycle of the Olympiad and its Panhellenic Games, and the calendar's 12 month names are of Corinthian origin.▰▰▱▱▱ likely2 points
Supports- The upper subsidiary dial is not a 76-year Callippic dial as previously thought, but follows the four-year cycle of the Olympiad and its associated Panhellenic Games.Freeth, Jones, Steele & Bitsakis, 'Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism', Nature 454 (2008), abstract authoritative
- Though no month names on the Metonic calendar were previously known, we have now identified all 12 months, which are unexpectedly of Corinthian origin.Freeth, Jones, Steele & Bitsakis, 'Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism', Nature 454 (2008), abstract authoritative
X-ray CT scanning in 2005 revealed extensive inscriptions buried inside the fragments; the back cover acted essentially as a user manual.▰▰▱▱▱ likely4 points
Supports- After years of struggle to get all the necessary permissions, this was finally carried out in 2005 by an Anglo-Greek team of researchers in collaboration with the National Archaeological Museum in Athens.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- The X-ray CT delivered another crucial revelation: extensive new inscriptions were buried inside the fragments and could now be read for the first time in over 2,000 years.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- The back cover essentially acted as a user manual, describing the principles on which the Mechanism was basedTony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- Here we report surface imaging and high-resolution X-ray tomography of the surviving fragments, enabling us to reconstruct the gear function and double the number of deciphered inscriptions.Freeth et al., 'Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism', Nature 444 (2006), abstract authoritative
The front cover inscription gives periods of 462 years for Venus and 442 years for Saturn, which the UCL team needed to incorporate into the gearing of its reconstruction; its lead author calls that reconstruction the first model that conforms to all the physical evidence.▰▰▱▱▱ likely5 points
Supports- The X-ray CT of the front cover inscription disclosed extensive new information about the planets.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- In 2016, Jones discovered the period 462 years in the Venus section of the inscription and 442 years in the Saturn section.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- Clearly, the UCL team needed to incorporate these periods into the gearing for Venus and Saturn.Tony Freeth, 'The Antikythera Mechanism: an ancient Greek machine rewriting the history of technology' (The Past / World Archaeology 108, 2021) authoritative
- Lead author Professor Tony Freeth (UCL Mechanical Engineering) explained: “Ours is the first model that conforms to all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the Mechanism itself.Experts recreate a mechanical Cosmos for the world's first computer (UCL News) analysis
- The Sun, Moon and planets are displayed in an impressive tour de force of ancient Greek brilliance.Experts recreate a mechanical Cosmos for the world's first computer (UCL News) analysis
Statistical techniques developed for gravitational-wave analysis indicate the calendar ring was vastly more likely to have had 354 holes, matching the lunar calendar, than 365 holes of the Egyptian calendar.▰▰▱▱▱ likely3 points
Supports- Astronomers from the University of Glasgow have used statistical modelling techniques developed to analyse gravitational waves to establish the likely number of holes in one of the broken rings of the Antikythera mechanismGravitational wave researchers cast new light on Antikythera mechanism mystery (University of Glasgow, 27 June 2024) analysis
- They show that the ring is vastly more likely to have had 354 holes, corresponding to the lunar calendar, than 365 holes, which would have followed the Egyptian calendar.Gravitational wave researchers cast new light on Antikythera mechanism mystery (University of Glasgow, 27 June 2024) analysis
- A ring of 360 holes is strongly disfavoured, and one of 365 holes is not plausible, given our model assumptions.Bayley & Woan, 'An improved calendar ring hole-count for the Antikythera mechanism', arXiv:2403.00040 authoritative
The Antikythera Mechanism is technically more complex than any known device for at least a millennium afterwards.▰▰▱▱▱ likely1 source
Supports- Named after its place of discovery in 1901 in a Roman shipwreck, the Antikythera Mechanism is technically more complex than any known device for at least a millennium afterwards.Freeth et al., 'Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism', Nature 444 (2006), abstract authoritative
Disputed 3credible sources disagree
The eclipse dial's epoch falls around 205 BC, earlier than the end-of-second-century-BC construction date proposed in 2006.▰▰▰▱▱ likely1 against3 points
Supports- And the eclipse predictor would work best if the full Moon of month 1 of the Saros dial corresponds to May 12, 205 BCE, with the exeligmos dial set at 0.Carman & Evans, 'On the epoch of the Antikythera mechanism and its eclipse predictor', Archive for History of Exact Sciences 68 (2014), abstract authoritative
- Together, these models imply a surprisingly early epoch for the Antikythera Mechanism.Freeth, 'Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism', PLOS ONE (2014) authoritative
Against- The Antikythera Mechanism is a unique Greek geared device, constructed around the end of the second century bc.Freeth et al., 'Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism', Nature 444 (2006), abstract authoritative
The Antikythera Mechanism's design has a heritage going back to Archimedes.▰▰▰▱▱ likely2 against4 points
Supports- The Corinthian colonies of northwestern Greece or Syracuse in Sicily are leading contenders-the latter suggesting a heritage going back to Archimedes.Freeth, Jones, Steele & Bitsakis, 'Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism', Nature 454 (2008), abstract authoritative
- one theory, apparently picked up by the movie’s creative team, attributes the technology used in the device to Greek mathematician ArchimedesThe Real History Behind the Archimedes Dial in 'Indiana Jones and the Dial of Destiny' (Smithsonian Magazine, interview with Jo Marchant) analysis
Against- And one of them he attributed to a philosopher named Posidonius, who lived on Rhodes in the first century B.C.E. at exactly the time scholars think the Antikythera ship would have stopped off at the island.The Real History Behind the Archimedes Dial in 'Indiana Jones and the Dial of Destiny' (Smithsonian Magazine, interview with Jo Marchant) analysis
- Still, much about the mechanism remains unknown, from its creatorThe Real History Behind the Archimedes Dial in 'Indiana Jones and the Dial of Destiny' (Smithsonian Magazine, interview with Jo Marchant) analysis
The mechanism's eclipse predictions draw on Babylonian arithmetic methods.▰▰▰▱▱ likely2 against4 points
Supports- The mechanism predicted lunar and solar eclipses on the basis of Babylonian arithmetic-progression cycles.Freeth et al., 'Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism', Nature 444 (2006), abstract authoritative
- Indeed, an arithmetic scheme for the eclipse times matches the evidence somewhat better than does a trigonometric model.Carman & Evans, 'On the epoch of the Antikythera mechanism and its eclipse predictor', Archive for History of Exact Sciences 68 (2014), abstract authoritative
Against- its design was a highly ingenious fusion of ancient Babylonian and Greek mathematical astronomy.Freeth, 'Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism', PLOS ONE (2014) authoritative
- combining cycles from Babylonian astronomy, mathematics from Plato’s Academy and ancient Greek astronomical theories.Freeth et al., 'A Model of the Cosmos in the ancient Greek Antikythera Mechanism', Scientific Reports (2021) authoritative
Debunked 1refuted by the evidence
The Antikythera mechanism could locate fissures in time and allow time travel.Refuted by
It’s essentially a pocket universe, like a model of the cosmos.
refuted2 against4 pointsThe claim rested on- the hero chases after the Archimedes Dial, a fictionalized version of the Antikythera mechanism that predicts the location of naturally occurring fissures in time.The Real History Behind the Archimedes Dial in 'Indiana Jones and the Dial of Destiny' (Smithsonian Magazine, interview with Jo Marchant) analysis
- While the movie version enabled the intrepid archaeologist to travel through timeGravitational wave researchers cast new light on Antikythera mechanism mystery (University of Glasgow, 27 June 2024) analysis
Refuted by- It’s essentially a pocket universe, like a model of the cosmos.The Real History Behind the Archimedes Dial in 'Indiana Jones and the Dial of Destiny' (Smithsonian Magazine, interview with Jo Marchant) analysis
- the Glasgow team’s results provide fresh evidence that one of the components of the Antikythera mechanism was most likely used to track the Greek lunar year.Gravitational wave researchers cast new light on Antikythera mechanism mystery (University of Glasgow, 27 June 2024) analysis
Unresolved 1no settled answer
Whether the mechanism actually worked is unresolved: a simulation found that estimated manufacturing errors significantly increase the likelihood of gear jamming or disengagement, so either it never functioned or its real errors were smaller than estimated.▰▰▰▱▱ likely4 points
Supports- Our findings indicate that while the triangular shape of the teeth alone produces negligible errors, manufacturing inaccuracies significantly increase the likelihood of gear jamming or disengagement.Szigety & Arenas, 'The Impact of Triangular-Toothed Gears on the Functionality of the Antikythera Mechanism', arXiv:2504.00327 authoritative
- Consequently, either the mechanism never functioned or its actual errors were smaller than those reported by Edmunds.Szigety & Arenas, 'The Impact of Triangular-Toothed Gears on the Functionality of the Antikythera Mechanism', arXiv:2504.00327 authoritative
- Since the impact of these variables is speculative, our results must be interpreted with caution.Szigety & Arenas, 'The Impact of Triangular-Toothed Gears on the Functionality of the Antikythera Mechanism', arXiv:2504.00327 authoritative
- However, Szigety thinks it’s unlikely that the gear box never moved, proposing instead that it didn’t have as many mechanical errors as Edmunds concluded.How Well Did the Mysterious Antikythera Mechanism Actually Work? (Smithsonian Magazine) summary
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