The mysterious device known as the Antikythera Mechanism has been puzzling scientists ever since it was discovered 115 years ago in an underwater shipwreck dating to about 70 BC. It has been called an “ancient computer,” an “astronomical calculator,” and a “mechanical cosmos.” While its importance was recognized almost immediately, unlocking the secrets of the device (which is extremely corroded) took over a century. The latest breakthroughs in understanding its inner workings were accomplished by an international team of researchers founded in 2005 called the Antikythera Mechanism Research Project.

Xenophon Moussas is professor of physics at the National and Kapodistrian University in Athens as well as a member of the Antikythera Mechanism Research Project and he joins us to shed light on this marvel from the ancient world. His book (available in Greek) is: The Antikythera Mechanism: “Pinax”.

To see 3d images of the device as well as x-ray scans, visit the Project's official page at

Also check out the amazing YouTube channel “Clickspring” to see a clockmaker building a replica of the mechanism piece by piece.

There were similar devices in antiquity that were spherical in shape. Cicero, for example, describes "spheres" of Archimedes. Michael Wright has constructed a working model of such a device.

The main part of the mechanism (front), as it is today on display at the National Archaeological Museum of Athens.
The back side of the main part of the mechanism.
Xenophon Moussas with his reconstruction of the device.
Computer generated exploded view of the device according to Tony Freeth's model.
Derek De Solla Price, author of the foundational "Gears from the Greeks," with his model of the mechanism.
Michael Wright in his workshop with his reconstruction.
Visualization of the four gears that move the moon. One gear moves a parallel but slightly-off-axis second gear via a pin-and-slot mechanism, thus generating a variable speed for the moon during the month.


Gears From the Greeks: The Antikythera Mechanism, a Calendar Computer from Ca 80 B.C. by Derek De Solla Price

A Portable Cosmos: Revealing the Antikythera Mechanism, Scientific Wonder of the Ancient World, by Alexander Jones

Decoding the Heavens: A 2,000-Year-Old Computer--and the Century-long Search to Discover Its Secrets, by Jo Marchant