Unlocking the Mystery of the Antikythera Mechanism

The discovery

In 1901 a group of sponge divers discovered a shipwreck off the coast of the Greek island of Antikythera which contained a treasure trove of various artifacts believed to be dating back to the 2^nd or 1^st century BCE. These included glassware, luxury ceramics, marble statues, tools and coins.

Amongst them was a wooden box-like structure which didn’t look like much in the beginning except the fact that it was green which showed that it was probably made of bronze.

Upon further inspection this unassuming box encased what was one of the world’s oldest known examples of a geared mechanism.

This was a startling discovery and unbelievable at the time, as gears like these should not have even existed in Ancient Greece, nor anywhere else in the world, until centuries later.

Deciphering the past

This lump that perplexed historians and scientists for more than 120 years came to be known as the “Antikythera Mechanism”. Some scientists dubbed it as the “world’s first analogue computer” because it is a machine with an entry to import data and obtain results based on a scientific mathematical scale.

The most likely inventors of the device are believed to be either Archimedes of Samos (or based on a design by him) or Hipparchus of Nicea depending on which date one accepts for the invention to have occurred.

It is estimated that it was originally the size of a shoebox and made of bronze. It had a front, back and central plate in which the gears were mounted, with a crank on one side.  Only one third of the mechanism was recovered and has been split into 82 fragments, leaving a difficult jigsaw puzzle for researchers to put back together.

Reconstucting its Complexity

It seems that the device was used to predict the positions of the sun, moon and planets on any specific day in the past or future by simply turning a crank to the desired time frame to see astronomical predictions. It also served to plan agricultural activities, coordinate religious ceremonies and navigate the seas during voyages. In addition, it would predict eclipses, star events, and track the four-year cycle of athletic games similar to those of an Olympiad, the cycle of the ancient Olympic Games.

In the 1970’s x-rays were used to study the fragments. It was discovered that it contained 30 gears at that time.

The model below was reconstructed in the 1970’s by Derek De Solla Price,  British physicist, historian of science, and information scientist.

In the 1990’s with the coming of the 3-D x-ray technique (linear tomography) scientists have reconstructed models of the mechanism’s gears, which helped visualize the inner workings of the device. The total number of gears now amounted to 69 with a 223-tooth gear at the back, a 127-tooth gear on one side, a 3-tooth gear on another side and a 5-tooth gear attached to that. These sizes of teeth on the gears were a critical step in understanding that the mechanism was more complicated than originally conceived.  

The model below was reconstructed in 1990 by Michael Wright, former curator of mechanical engineering at London’s Science Museum.

In 2005, with the advancement in technology, Tony Freeth and his team used CT Scans which revealed inscriptions on the back plate which seemed to be a user manual for the device.  The front plate was divided into five sections corresponding to the five known planets; Mercury, Venus, Mars, Saturn and Jupiter.

The image below shows the inside of the device and how the mechanism is believed to have worked.

Conclusion

The discovery of the Antikythera Mechanism stands as a testament to the genius of ancient civilizations. It represents an astonishing feat of engineering and the intellectual mastery of the ancient Greek astronomers and engineers.

Today you can admire the Antikythera mechanism in the Bronze collection of the National Archeological Museum of Athens.

Want to know more:

https://www.thearchaeologist.org/blog/how-does-the-antikythera-mechanism-work

https://www.antikythera-mechanism.gr/project/overview

https://www.antikythera-mechanism.gr/

“Gears from the Greeks” paper by Derek J. de Solla Price