The Antikythera Mechanism - Archaeology Magazine Archive


The Antikythera Mechanism	Volume 60 Number 2, March/April 2007
by Jarrett A. Lobell

New imaging technology reveals the soul of the world's first computer.

The Antikythera Mechanism is the earliest bronze geared device ever found. Each of its 30 gears has between 15 and 223 triangular teeth. Turning a knob on the side of the mechanism would have engaged the largest wheel, which rotated once for every year. Other gears governed the sun, moon, planets, and the pointers on two calendrical spirals. A CT X-ray image, right, reveals complex inner workings of the mechanism heretofore hidden beneath its corroded surface, left. (© Antikythera Mechanism Research Project)

There may be nothing new under the sun after all. It's been more than two millennia since a large ship went down off the coast of the Greek island of Antikythera, and more than a century since a sponge diver discovered the ship's valuable cargo, which included bronze and marble statues, pottery, and glass and silver vases. But only now have researchers deciphered one of the wreck's--and classical archaeology's--most enigmatic artifacts: a corroded collection of bronze and wood fragments known as the Antikythera Mechanism.

It is almost impossible to identify by eye many of the inscriptions on the corroded surface of the mechanism. (© Antikythera Mechanism Research Project)

From early on, archaeologists identified pieces of inscribed gear wheels within the corroded lump, which led to the consensus that it was some sort of astronomical device. Throughout the twentieth century, from its home in the National Archaeological Museum in Athens, the Antikythera Mechanism attracted sporadic visits from archaeologists and historians who marveled at its highly complex, precise, hand-cut gear system and the undeciphered inscriptions on both the gears and wooden casing. The mechanism attracted sporadic scientific interest, including X-ray studies in the 1970s and '90s, but no one could completely understand its nature. How exactly did it work, and for what had it been used? Could such a sophisticated device have been created more than 1,400 years before similar objects were known to exist anywhere else in the world?

Currently, the multinational Antikythera Mechanism Research Project (AMRP), led by mathematician and filmmaker Tony Freeth, is using innovative imaging technology to answer these questions. After 4 years of trying, Freeth's 17-person team of archaeologists, historians, and computer programmers, finally received permission from the museum to study the mechanism's 7 main and 75 smaller fragments. The AMRP team was concerned that handling the 2,200-year-old device would irrevocably damage it, so they turned to technology. Innovative lighting techniques and 3-D X-ray computerized tomography (CT) have allowed the team to reconstruct the mechanism's gear functions and double the number of deciphered inscriptions, giving a view into an ancient world that had much more knowledge about the solar system than previously thought.

Jarrett A. Lobell is associate managing editor at ARCHAEOLOGY.

To see the HP images of the Antikythera Mechanism and to try their imaging technique for yourself, visit the HP Labs website at www.hpl.hp.com.