2,100-year-old astronomical calculator tracked Olympics

ATHENS, Greece -- An astronomical calculator, considered a technological marvel of antiquity, was also used to track dates of the ancient Olympic games, researchers have found.

Experts from Britain, Greece and the United States said they have detected the word "Olympia" on a bronze dial, as well as the names of other games in ancient Greece on the device known as the Antikythera Mechanism.

Their findings will be reported today in the British science journal Nature.

The 2,100-year-old Antikythera Mechanism was recovered from an ancient shipwreck in 1901 near Antikythera, a small island off Greece's south coast.

Its insides look like a clock. About 30 bronze gears were cranked to calculate phases of the moon, eclipses and other celestial information specific to a certain date. Results were displayed on dials on the front and back of the mechanism.

Most workings of the device only came to light with recent advances in scanning technology and computer processing power.

In 2005, an X-ray tomography machine was brought from Britain to the National Archaeological museum of Athens, which houses the device's corroded and sediment-encrusted remains. Researchers soon found the gear structure -- including the number of teeth cut into the wheels -- corresponded to known theories of celestial cycles.

"It's like a medical scanner, but instead of putting people in it, we put the Antikythera Mechanism," Yanis Bitsakis, a co-author of the Nature report, said of the technology used to study the device.

Bitsakis, of Athens University's Center for History and Paleography, said finding the Olympian dial on the device was a surprise. Greece's ancient games had important religious significance and were commonly used dates for historical reference.

"We were astonished because this is not an astronomic cycle but an Olympian cycle, one of social events ... One does not need a piece of high technology to keep track of a simple four-year cycle," he said. "It is perhaps not extravagant to see the mechanism as a microcosm illustrating the temporal harmonization of human and divine order."

In a second new find, also reported in Nature on Thursday, Bitsakis and fellow researchers found that month names etched onto the Antikythera Mechanism were consistent with ones used in Corinthian colonies in Sicily. This provides the first possible link with the Greek mathematician Archimedes, who died there about 100 years before the device was built, Bitsakis said.

"This is an interesting -- not direct link but possible link -- with the town where Archimedes used to work. It is the first link of this kind," he said.

With the powerful 3-D scanner, built by the British-based X-Tek Systems, scientists can peer into razor-thin sections of the device's 80-odd surviving fragments to understand its mechanics and read hundreds of tiny Greek inscriptions etched onto its bronze components.

Information was also gleaned from a technique developed by U.S.-based Hewlett-Packard Co. which made composite images of high-resolution digital photographs taken of the mechanism fragments under varied lighting conditions.

Bitsakis said improved computing power, used to analyze existing scans and images, made the latest discovery possible.

"The inscriptions are in very faint layers, like one-tenth of a millimeter in depth, and the letters are 1 millimeter high, so it's almost nothing," he said.

"(We had better) memory processing power and more powerful graphic cards ... Without this we couldn't see the inscription because you have to increase the resolution and the result is a very big file," he said.

The ongoing research project into the Antikythera Mechanism is being led by Mike Edmunds, professor of astrophysics, and his colleagues at Cardiff University in Britain.