Greek solar computer reconstructed

New research into an ancient Greek artefact has revealed that it was a sophisticated calculating machine capable of accurately predicting solar eclipses and the movement of the planets.

The Antikythera Mechanism was recovered from the seabed off Greece over a hundred years ago and was at first ignored and then identified as an early clock. But in a paper published in Nature, mathematician and filmmaker Tony Freeth and the astronomer Mike G. Edmunds, both of the University of Cardiff, Wales, say that the device is much more complex than first thought.

"I'm very surprised to find a mechanical representation of this," adds Alexander Jones, a historian of astronomy at the University of Toronto, Canada.

He says the Antikythera Mechanism has had little impact on the history of science so far. "But I think that's about to change. This was absolutely state-of-the-art in astronomy at the time."

The device had at least 30 and as many as 37 hand carved gear wheels and was operated by a hand crank. Detailed analysis of the corroded remains shows references to the planets and lunar and solar eclipses.

Such technology was not seen again for a thousand years, and the device is thought to have been able to accurately predict the movements of the five known planets of the time. It was found in the remains of a Roman ship in among a cargo from the Greek island of Rhodes.

The ancient Greeks were the first recorded group in human history to understand that the world was round and orbited the sun, a view the Christian church only acknowledged a thousand years later. Two hundred years before the birth of Christ, the Greek astronomer Eratosthenes accurately predicted the circumference of the earth to within 50 miles of its presently accepted value.