Sometime before Easter 1900 a Greek sponge diver discovered the wreck of an ancient cargo ship off Antikythera island which is located to the north-west of Crete in the Dodecanese.
Divers subsequently retrieved several bronze and marble statues and other artifacts from the site.
The interest of the professional archaeologists brought in to conserve and assess the finds was initially centered on the fine statuary and the Antikythera Mechanism itself was only discovered to be of immense interest in May 17, 1902, when an archaeologist noticed that a piece of rock recovered from the site had a gear wheel embedded in it. Examination revealed that the “rock” was in fact a heavily encrusted and corroded mechanism that had survived the shipwreck in three main parts and dozens of smaller fragments. The device itself was surprisingly thin, about 33 cm (13in) high, 17 cm (6.75in) wide and 9 cm (3.5in) thick, made of bronze and originally mounted in a wooden frame.
The Antikythera mechanism is one of the world’s oldest known geared devices. It has puzzled and intrigued historians of science and technology since its discovery. The device seemed to have a range of interlocking gears made of bronze and a hand crank to give a turning movement to the geared mechanism, plus a display that showed information about the moon, sun and planets against a background of stars.
Following decades of work cleaning the device, in 1951 British science historian Derek J. de Solla Price undertook systematic investigation of the mechanism. In June 1959, Price’s “An Ancient Greek Computer” was the lead article in Scientific American. This article was the result of the first thorough description of the device “based solely on visual inspection and measurements.”
The Antikythera Mechanism is strongly suggestive of an ancient Greek tradition of complex mechanical technology which, transmitted via the Arab world, formed the basis of European clockmaking techniques.
Another, smaller, device dating from the sixth century AD, has been discovered which models the motions of the sun and moon and provides a previously missing link between the Antikythera mechanism and later Islamic calendar computers, such as the 13th century example at the Museum of the History of Science in Oxford. That device, in turn, uses techniques described in a manuscript written by al-Biruni, an Arab astronomer, around 1000AD.
The device was too fragile to be removed from its home at the National Archaeological Museum of Athens, so the Antikythera Mechanism Research Project team constructed a 12-ton portable micro focus computerized tomographer that used high resolution X-rays to probe the object and create a 3-dimensional image.
A reinterpretation of the function of the various fragments by Michael Wright of Imperial College London developed between 2002 and 2005 arrived at an entirely different assembly for the gears than previously thought.
Wright’s reconstruction of the device, with 72 gears, suggests it may have been an orrery that was intended to mechanically demonstrate the motions of the five planets known to the Greeks of the time.