Researchers home in on possible “day zero” for Antikythera mechanism

The Antikythera mechanism, an ancient device believed to have been used for tracking the heavens, has fascinated scientists and the public alike since it was first recovered from a wreck over a century ago. In recent years, much progress has been made to reconstruct the surviving fragments and learn more about how the mechanism might have been used. According to a preprint posted to the physics arXiv, members of a team of Greek researchers believe they have pinpointed the start date for the Antikythera mechanism. Ensuring the accuracy of the device is dependent on knowing day zero.

Any measuring system, from a thermometer to the Antikythera mechanism, needs a calibration in order to perform its calculations correctly.

The wreck of an ancient cargo ship was discovered by a Greek sponge diver in 1900. The divers recovered a lot of artifacts from the ship. Valerios Stais, an Archeologist, was studying a piece of rock that he thought was from the wreck when he noticed a gear wheel embedded in it. It was an ancient mechanical device. The National Archaeological Museum of Athens houses the Antikythera mechanism.

The theoretical workings of the device were being investigated by a British science historian. The paper was published in 1959 in the Transactions of the American Philosophical Society. They believed that the mechanism had been used to calculate the motions of stars and planets, making it the first known analog computer.

In 2002, Michael Wright, then curator of mechanical engineering at the Science Museum in London, made headlines with new, more detailed X-ray images of the device. Wright found a fixed central gear in the mechanism's main wheel. He concluded that the device was designed to model the motion of the stars in keeping with the ancient Greek idea of epicycles. The point at which they moved was believed to be the Earth.

A team led by mechanical engineer Tony Freeth made global headlines last year with their model of the ancient Greek universe. The team is using modern machinery to build a replica mechanism. The display is described in the inscriptions on the mechanism's back cover, with planets moving on rings with markers as indicators. The X-rays on the front cover show the cycles of Venus and Saturn.

More advanced 3D X-ray imagery was undertaken with the help of X-Tek Systems in the UK and Hewlett-Packard, among others, thanks to the efforts of the team built on Wright's work. More of the original Greek transcription was revealed in the new images. The computer was used to predict the positions of heavenly bodies in the sky. It is possible that the Antikythera mechanism used to have 37 gears, 30 of which have survived, and graduations showing the solar cycle and the zodiac, along with pointers to indicate the positions of the Sun and Moon.