Using advanced new imaging techniques, scientists have reconstructed the gear structure of the mysterious Antikythera mechanism—one of the world's oldest computers.

The researchers also deciphered previously hidden text from the astronomical calculator, which dates back to around 100 B.C.

The new research, which appears in tomorrow's issue of the journal Nature,confirms that the ancient Greeks had developed extremely sophisticated levels of craftsmanship and scientific knowledge.

The intricate bronze instrument has puzzled scientists ever since it was recovered in A.D. 1901. The device was one of many treasures found in a Roman shipwreck discovered by a sponge diver just off Antikythera island, off the southern coast of Greece (map of Greece).

Saltwater had corroded the shoebox-size instrument, and the moving parts had long since seized up.

In 1959 British science historian Derek Price put forward the idea that the Antikythera mechanism was a device for displaying the motions of moons and planets.

In the past five years Michael Wright, from Imperial College London in England, confirmed this theory using X-rays to reveal the layering of the gear wheels.

The device employs an elaborate arrangement of more than 30 gears for its calculations. The level of miniaturization and complexity is remarkable, with some parts resembling those used by 18th-century clockmakers.

"It is extraordinarily sophisticated," said Stephen Johnston, an expert on astronomical calculators from the Museum of the History of Science at the University of Oxford in England.

"In its complexity it exceeds medieval cathedral clocks, which were developed over a thousand years later."