HP researchers are helping members of the Antikythera Research Project learn how the ancient astronomical device — possibly the world's oldest computer — works.

The Antikythera Mechanism is an ancient astronomical device built by the Greeks around 80 B.C. and found on a shipwreck off the Greek island of Antikythera by sponge divers in 1901. It is believed to have been created to track lunar and solar cycles for agricultural and religious purposes, but its precise function – and how it works – has eluded scholars for more than a century.

Members of the Antikythera Research Project invited HP Labs research scientists Tom Malzbender and Dan Gelb to Athens to apply their patented reflectance imaging techniques to the front and rear surfaces of the more than 70 fragments that comprise the mechanism, including metal plates and gears, some of which are inscribed with faded Greek characters.


The technique involves taking photos of an artifact from a fixed point and 50 different light sources arrayed in a hemisphere over the object. The computer program then ties the images together, enabling an archaeologist to change the angle of light or texture of the surface of the object to make faint markings appear more vivid. The new research explains how the gears work and identifies twice as many markings on the device as previously detected.

"One of the advantages of reflectance imaging is that you can change the quality of the surface of an object, by, for example, making dull surfaces shiny, like obsidian", said Gelb, senior research scientist, HP Labs. "That way, the faint markings on these ancient artifacts become more visible and that helps scholars determine their meaning."

By capturing the images digitally, the technique also enables scholars around the world to study the rare, delicate objects without having to travel to where they're stored or to handle them. The technology was originally developed not for archaeology, but as a method for improving photorealism and rendering efficiency in 3D graphics. It also could be used in criminal forensics, detecting distinctive characteristics in footprints or tire marks.

The results of Malzbender and Gelb's work, in collaboration with researchers from the U.K. and Greece, are in the British science journal, Nature ("Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism"). The other researchers used an X-ray technique, called computer tomography, to probe the depths of the device.

"The Antikythera Mechanism is the only technological device from the ancient world and the oldest computer or calculator known to man," said Malzbender, technologist, HP Labs. "Nothing like it appears until the Renaissance, when clocks first appeared."

Read more here.