The Antikythera Mechanism: The World’s Oldest Computer
The Antikythera mechanism is one of those artefacts which has simultaneously baffled and fascinated archaeologists and engineers since its discovery. Recovered in 1990 by a group of divers, it took a century for its true significance to be uncovered and it still confounds experts to this day. The Antikythera mechanism is a device which displays technology some 1400 years before its technology has been estimated to have been invented. What’s more, from all current research into the Hellenistic age, general thought concludes that this kind of technology could simply not have existed at this time, and yet the Antikythera mechanism stands in utter contradiction to what we think we know. This article will give an overview of exactly what the Antikythera mechanism is and why it captures the imagination of so many around the world.
Discovery and Origins
In October 1900 a group of divers, led by Captain Dimitris Kondos, decided to wait out a bad storm on the Greek island of Antikythera during their journey back from Africa. As they waited divers decided to explore waters off the island for sponges, but instead came across a vast shipwreck dating back to the 2nd quarter of the 1st century BC. Amongst a huge hoard of artefacts recovered, mainly statues, was a gear wheel embedded in a piece of rock, which is now known to be the first example of a computer mechanism ever recorded.
The Antikythera mechanism has been dated back to around 100BC and is believed to have been made of low-tin bronze alloy, although corrosion has impaired precise compositional analysis. On first inspection the mechanism echoes the workings of a traditional timepiece, but with further analysis experts have discovered that the Antikythera clock was actually a complex computer designed to map astronomical positions. Its design is based of Greek theories of astronomy and mathematics and all instructions are written in Koine Greek, indicating that this was a piece of machinery designed for the Greek speaking world.
Various hypothesises have been proposed as to the original maker of this computer, from the stoic philosopher Posidonius, to the astronomer Hipparchus and even connections with Archimedes have been theorised. One thing most experts agree on is that this kind of technology is anachronistic; seemingly too complex in engineering to have been designed in the same period as other machinery that has been discovered from around this time. This tantalising piece then questions our entire understanding of engineering in antiquity and has challenged scholars with the possibility of completely re-assessing our understanding of ancient technology.
Mechanism
The mechanism of the Antikythera clock is remarkably complex and comparable to the classic Victorian timepiece. It has at least 30 different gears; some claim that as many as 72 are present. The gears are combined with keyed sprockets and a hand crank is used as linear actuator converting rotational motion in linear motion. When a date is entered, either in the future or the past via the crank, the position of the sun, moon and other astronomical data like planets is charted. The front dial of the piece provides the only known example of a scientifically graduated instrument from antiquity and its accuracy is astonishing. Under microscope, the average error of the graduation over the visible 45 degrees is about a quarter of a degree.
The mechanism has three main dials, one on the front and two on the back. The front dial has two concentric scales; the outer ring marking the 365-day Sothic cycle, and the inner ring marked with the signs of the Zodiac divided into degrees. This front dial has three hands indicating the date and both the sun and moon and a mechanism known as a parapegma, similar to the modern almanac, which charts the rising and setting of stars.
The back dials display both the 19-year Metonic cycle, the 4 year Olympiad cycle and the Saros. The first has 47 divisions per turn and the second 223 divisions. The computer is thus a hugely complex, and fascinatingly precise time keeper. The accuracy of the mechanism was demonstrated by an engineer who rebuilt the Antikythera clock using lego and managed to accurately predict a solar eclipse due on 8th April 2024.
The Antikythera Mechanism potentially calls for academics and scholars throughout the world to reassess their understanding of ancient technology and engineering. On its own it is an exquisite piece of engineering, but put in historical context it has potentially revolutionary ramifications which make it one of the most fascinating discoveries of the modern era.