The Antikythera Mechanism: Hacking with Gears

The Mechanism of Antikythera is an astronomical calculator from the first century B.C. Its currently agreed-on model consists of 35 gears. Its back face contains four dials tracing a luni-solar calendar and an eclipse prediction table. A number of interlocked gears calculate the ratios required for moving the four dials. The front face shows the sun's and the moon's positions in the zodiac. The elliptical anomaly of the moon is calculated by advancing one gear eccentrically through another and mounting that assembly on a gear rotating according to the moon's long axis precession period. The mechanism's design eerily foreshadows a number of modern computing concepts from the fields of digital design, programming, and software engineering.

The talk will briefly go over the mechanism's provenance and the modern history of its study, focusing on recent findings that an international cross-disciplinary team of scientists obtained through surface imaging and high-resolution X-ray tomography. The talk will offer a detailed explanation of the mechanism's operation by presenting a Squeak EToys-based emulator that is built and operates entirely on mechanical principles.