Ancient Astronomical Calculator Demystified

An international team has unravelled the secrets of a 2,000-year-old computer which could transform the way we think about the ancient world.

Professor Mike Edmunds and Dr Tony Freeth, of Cardiff University led the team who believe they have finally cracked the workings of the Antikythera Mechanism, a clock-like astronomical calculator dating from the second century BC.

Remnants of a broken wooden and bronze case containing more than 30 gears was found by divers exploring a shipwreck off the island of Antikythera at the turn of the 20th century. Scientists have been trying to reconstruct it ever since. The new research suggests it is more sophisticated than anyone previously thought.

Detailed work on the gears in the mechanism shows that it was able to track astronomical movements with remarkable precision. The calculator was able to follow the movements of the moon and the sun through the Zodiac, predict eclipses and even recreate the irregular orbit of the moon. The team believes it may also have predicted the positions of some or all of the planets.

The findings suggest that Greek technology was far more advanced than previously thought. No other civilisation is known to have created anything as complicated for another thousand years.

Professor Edmunds said: "This device is just extraordinary, the only thing of its kind. The design is beautiful, the astronomy is exactly right. The way the mechanics are designed just makes your jaw drop. Whoever has done this has done it extremely well."

The team was made up of researchers from Cardiff, the National Archaeological Museum of Athens and the Universities of Athens and Thessaloniki, supported by a substantial grant from the Leverhulme Trust. They were greatly aided by Hertfordshire X-Tek, who developed powerful X-Ray computer technology to help them study the corroded fragments of the machine. Computer giant Hewlett-Packard provided imaging technology to enhance the surface details of the machine.

The mechanism is in over 80 pieces and stored in precisely controlled conditions in Athens where it cannot be touched. Recreating its workings was a difficult, painstaking process, involving astronomers, mathematicians, computer experts, script analysts and conservation experts.

The team is unveiling its full findings at a two-day international conference in Athens from November 30 to December 1 and publishing the research in the journal Nature. The researchers are now hoping to create a computer model of how the machine worked, and, in time, a full working replica. It is still uncertain what the ancient Greeks used the mechanism for, or how widespread this technology was.

Professor Edmunds said: "It does raise the question what else were they making at the time. In terms of historic and scarcity value, I have to regard this mechanism as being more valuable than the Mona Lisa."