CT scanning helped reveal complex mysteries of Antikythrea Mechanism
In an exciting link-up between high-tech industry and international universities, the secrets of a 2000 year old astronomical calculating device – the Antikythera Mechanism – were unraveled. Researchers counted on the unique 400kV microfocus computed tomography (CT) system. The outcome not only led to an astonishing new theory of how the mechanism worked, but also to the reading of inscriptions that remained unseen for more than 2000 years.
Named after its place of discovery in 1901 in a Roman shipwreck, the Antikythera Mechanism is technically more complex than any other device for at least a millennium afterwards. The team of scientists behind the Antikythera Mechanism Research Project succeeded in solving the puzzle of its purpose. Project results confi rm that the mechanical computer was designed to track the movements of heavenly bodies, specifically the sun, moon and planets.
Although the mechanism is no bigger than a shoe box, it is too priceless and unique to leave the National Archaeological Museum in Athens, so a major expedition in late 2005 brought a 400kV microfocus Nikon tomography machine – weighing over 7.500kg – to examine the artifact in Greece. Originally designed to search for imperfections in turbine blades and other industrial devices, the Nikon machine creates astonishingly detailed 3D X-ray images.
The imaging equipment has been instrumental in advancing our current understanding of the mechanism. It was originally thought that the CT results would be vital in producing good images of the gear train, allowing researchers to obtain good teeth counts for the mechanism’s gears, and finally resolving any arguments regarding the relationships between the gears. The CT results have achieved this, and much more.
The results have revealed many more details of the mechanism, including the so-called ‘pointer follower’ in Fragment B, which allows the back dial to be interpreted as spiral dials, not circular dials as previously thought. 3D CT images have also revealed the pin and slot mechanism that has allowed researchers to discover that the mechanism models the first anomaly of the Moon’s motion.