The Greek Antikythera: The World’s First Computer

In 1900 and 1901, divers retrieved three bronze fragments from a shipwreck near the island of Antikythera in the Mediterranean Sea. The pieces were very corroded, but markings of an ancient technology remained evident. One fragment contained a gear with teeth, just like in a mechanical clock. Another piece was a ring with degrees marked along the edge. What was this thing?

It would be decades before modern technology would be able to answer this question. In the 1970s, scientists began using x-rays to look beyond the corrosion and glean more information about this device. They saw that it simulated the motions of the heavens. Dates for its creation range from 60 BCE to 205 BCE, over 2000 years old. The ancient Greeks had been able to accurately predict the paths of the planets, the Sun, and the Moon! Compared to other gadgets of its time, the Antikythera was incredibly sophisticated.

In 2006, another scientist applied a newer technology, computer-aided tomography (CT), to the Antikythera puzzle. The CT scan revealed more details about the mechanics of the device and some previously unnoticed inscriptions.

So what is now known about the Antikythera? A 2015 Smithsonian magazine article reported that this device was most likely housed in a wooden case and looked like a mantel clock. It had at least seven rotating hands displayed on a circular face. A side knob or handle was used to wind it. The hands were driven by interlocking gears and moved at different rates. Instead of time in hours and minutes, the Antikythera kept celestial time, with:

“… one hand for the Sun, one for the Moon and one for each of the five planets visible to the naked eye—Mercury, Venus, Mars, Jupiter and Saturn. A rotating black and silver ball showed the phase of the Moon. Inscriptions explained which stars rose and set on any particular date. There were also two dial systems on the back of the case, each with a pin that followed its own spiral groove, like the needle on a record player. One of these dials was a calendar. The other showed the timing of lunar and solar eclipses.”

Inscriptions on the device suggest that the device could have been created near Corinth or the island of Rhodes. The Greek writer Cicero wrote about a bronze device invented by Archimedes in the third century BCE. The astronomer Hipparchus of Rhodes, living in the 2nd century BCE, also contributed to working out the math behind the movement of celestial bodies. Cicero also wrote about an Antikythera-like model created by Posidonius in the first century BCE.

In 2021, researchers at University College London constructed a computer model of the Antikythera. What information did they use to do this? They used the 82 recovered fragments of the Antikythera itself, estimated to be only one-third of the original device, and the previous modern research done on the artifact. They also relied on “a mathematical model of how the planets moved that was first devised by the ancient Greek philosopher Parmenides.“  You can see a picture of their model in the attachment below.

These researchers now have a new challenge in mind. They plan to build a working model of the Antikythera in physical space. They will begin by making one using modern techniques. After that, they will try to create one using ancient techniques. As one researcher commented: “There’s no evidence that the ancient Greeks were able to build something like this. It really is a mystery… The only way to test if they could is to try to build it the ancient Greek way.”

Did the Antikythera really work? And what was it used for? Only time will tell.