Ancient clock displays Olympic calendar and astronomical cycles


The Antikythera Mechanism is a two-thousand year-old clock made in Greece that was discovered a century ago in a shipwreck. Two years ago, scientists studying the bits and pieces that survived under the sea were able to figure out that the device was used to calculate astronomical cycles. Now though, British mathematician Tony Freeth, part of the original research group, has determined that the Antikythera Mechanism also shows the timetables of the Olympic Games. Freeth and his colleagues published their findings in this week's issue of the science journal Nature. The magazine also posted a fascinating video telling the clock's story. It's a marvelous tale of technology, history, and curiosity. From Nature News:

The device had intermeshed toothed wheels that represent calendar cycles. By turning the wheels, a user could figure out the relationships between astronomical cycles to deduce the relative positions of the Sun and Moon and forecast eclipses.

But after two millennia under the sea off the island of Antikythera, near Crete, all that remains of the device are 82 fragments of flaking bronze, including parts of 30 gear-wheels2. The numbers of gear teeth are crucial, but must be inferred from the partial wheels that remain. And most of the inscriptions are hidden under corrosion and surface accretions. To read them, the researchers used a method called microfocus X-ray computed tomography, which provides X-ray images of slices through the sample, revealing inscriptions buried beneath the mechanism's surface.

Antikythera Mechanism video
"Complex clock combines calendars" Nature News article
"Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism" paper