May 172017
 

On this date in 1902, archaeologist Valerios Stais found among some pieces of rock that had been retrieved from the Antikythera shipwreck in Greece 2 years earlier, one piece of rock that had a gear wheel embedded in it. Stais initially believed it was an astronomical clock, but most scholars at the time considered the device to be an anachronism of some sort, too complex to have been constructed during the same period as the other pieces that had been discovered with it (dated around the 1st and 2nd centuries BCE). Nope !! What is now called the Antikythera mechanism is, in fact, an ancient Greek analogue computer and orrery used to predict astronomical positions and eclipses for calendrical and astrological purposes, as well as a four-year cycle of athletic games that was similar, but not identical, to an Olympiad, the cycle of the ancient Olympic Games.  Nothing like it would re-emerge in Europe for 15 centuries. There is so much about the ancient world that remains a mystery (Stonehenge, the Pyramids, etc.).

The Antikythera mechanism was found to be housed in a 340 mm (13 in) × 180 mm (7.1 in) × 90 mm (3.5 in) wooden box but full analysis of its form and uses has only recently been fully performed.  In fact after Stais discovered it, it was ignored for 50 years, but then gradually scientists of various stripes, including historians of science, looked into it, and research into the mechanism is ongoing. Derek J. de Solla Price of Yale became interested in it in 1951, and in 1971, both Price and Greek nuclear physicist Charalampos Karakalos made X-ray and gamma-ray images of the 82 fragments.

The mechanism is clearly a complex clockwork device composed of at least 30 meshing bronze gears. Using modern computer x-ray tomography and high resolution surface scanning, a team led by Mike Edmunds and Tony Freeth at Cardiff University were able to look inside fragments of the crust-encased mechanism and read the faintest inscriptions that once covered the outer casing of the machine. Detailed imaging of the mechanism suggests it dates back to around 150-100 BCE and had 37 gear wheels enabling it to follow the movements of the moon and the sun through the zodiac, predict eclipses and even recreate the irregular orbit of the moon. The motion, known as the first lunar anomaly, was first described by the astronomer Hipparchus of Rhodes in the 2nd century BCE, and so it’s possible that he was consulted in the machine’s construction. Its remains were found as one lump later separated into three main fragments, which are now divided into 82 separate fragments after conservation work. Four of these fragments contain gears, while inscriptions are found on many others. The largest gear is approximately 140 mm (5.5 in) in diameter and originally had 224 teeth.

It is not known how the mechanism came to be on the sunken cargo ship, but it has been suggested that it was being taken from Rhodes to Rome, together with other looted treasure, to support a triumphal parade being staged by Julius Caesar. The mechanism is not generally referred to as the first known analogue computer, and the quality and complexity of the mechanism’s manufacture suggests it has undiscovered predecessors made during the Hellenistic period.

In 1974, Price concluded from the gear settings and inscriptions on the mechanism’s faces that it was made about 87 BCE and lost only a few years later. Jacques Cousteau and associates visited the wreck in 1976 and recovered coins dated to between 76 and 67 BCE. Though its advanced state of corrosion has made it impossible to perform an accurate compositional analysis, it is believed the device was made of a low-tin bronze alloy (of approximately 95% copper, 5% tin). All its instructions are written in Koine Greek, and the consensus among scholars is that the mechanism was made in the Greek-speaking world.

In 2008, continued research by the Antikythera Mechanism Research Project suggested the concept for the mechanism may have originated in the colonies of Corinth, since they identified the calendar on the Metonic Spiral as coming from Corinth or one of its colonies in Northwest Greece or Sicily. Syracuse was a colony of Corinth and the home of Archimedes, which, so the Antikythera Mechanism Research project argued in 2008, might