1. Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff CF24 3AA, UK
2. Images First Ltd, 10 Hereford Road, South Ealing, London W5 4SE, UK
3. National and Kapodistrian University of Athens, Department of Astrophysics, Astronomy and Mechanics, Panepistimiopolis, GR-15783, Zographos, Greece
4. Aristotle University of Thessaloniki, Department of Physics, Section of Astrophysics, Astronomy and Mechanics, GR-54124 Thessaloniki, Greece
5. Centre for History and Palaeography, National Bank of Greece Cultural Foundation, P. Skouze 3, GR-10560 Athens, Greece
6. National Archaeological Museum of Athens, 1 Tositsa Str., GR-10682 Athens, Greece
7. X-Tek Systems Ltd, Tring Business Centre, Icknield Way, Tring, Hertfordshire HP23 4JX, UK
8. Hewlett-Packard Laboratories, 1501 Page Mill Road, Palo Alto, California 94304, USA
9. Foxhollow Technologies Inc., 740 Bay Road, Redwood City, California 94063, USA

Correspondence to: M. G. Edmunds¹ Correspondence and requests for materials should be addressed to M.G.E. (Email: mge@astro.cf.ac.uk).

The Antikythera Mechanism is a unique Greek geared device, constructed around the end of the second century bc. It is known^{1, 2, 3, 4, 5, 6, 7, 8, 9} that it calculated and displayed celestial information, particularly cycles such as the phases of the moon and a luni-solar calendar. Calendars were important to ancient societies¹⁰ for timing agricultural activity and fixing religious festivals. Eclipses and planetary motions were often interpreted as omens, while the calm regularity of the astronomical cycles must have been philosophically attractive in an uncertain and violent world. Named after its place of discovery in 1901 in a Roman shipwreck, the Antikythera Mechanism is technically more complex than any known device for at least a millennium afterwards. Its specific functions have remained controversial^{11, 12, 13, 14} because its gears and the inscriptions upon its faces are only fragmentary. Here we report surface imaging and high-resolution X-ray tomography of the surviving fragments, enabling us to reconstruct the gear function and double the number of deciphered inscriptions. The mechanism predicted lunar and solar eclipses on the basis of Babylonian arithmetic-progression cycles. The inscriptions support suggestions of mechanical display of planetary positions^{9, 14, 15}, now lost. In the second century bc, Hipparchos developed a theory to explain the irregularities of the Moon's motion across the sky caused by its elliptic orbit. We find a mechanical realization of this theory in the gearing of the mechanism, revealing an unexpected degree of technical sophistication for the period.

MORE ARTICLES LIKE THIS

These links to content published by NPG are automatically generated.