Mystery of the Antikythera Mechanism, The Oldest Known Analogue Computer

The Antikythera mechanism, a marvel often heralded as the oldest known analogue computer, reveals a saga of ancient ingenuity and modern discovery.

Imagine a device so advanced it could predict eclipses, track the movements of planets, and even account for lunar irregularities – all in the 2nd century BC! This isn’t science fiction; it’s the reality of the Antikythera mechanism, an astonishingly complex astronomical calculator discovered in a shipwreck off the coast of Greece in 1901. For over a century, it has captivated scientists, historians, and the public alike, its intricate gears and bronze components whispering tales of forgotten knowledge and technological prowess. Who made it, how did it work, and what was its purpose?

The modern story of the Antikythera mechanism began unexpectedly, when sponge divers were exploring the wreckage of an ancient ship that was carrying a cargo of luxury items from Asia Minor to Rome when it sank sometime in the first century BC off the Greek island of Antikythera, located between the Peloponnese and Crete in the Mediterranean Sea. Among the treasures retrieved from the wreck were statues, jewellery, pottery, and the remains of the Antikythera mechanism, which was initially overlooked as a lump of corroded metal.

Yet, one archaeologist, Valerios Stais, recognized the potential significance of these unusual pieces. Further investigation revealed that the mechanism was a sophisticated device for calculating the solar and lunar calendar that could simulate the motion of the sun, moon, and five planets known to the ancient Greeks, as well as predict eclipses and and the movements of other stars and planets known at that time.

The Antikythera mechanism had more than 30 gearwheels, some with dozens of teeth, that were connected to dials and pointers on the front and back of the device. The user could turn a handle to move the gears and see the positions of the heavenly bodies at any given date. The mechanism also had inscriptions that explained its functions and instructions for its use.

Understanding the mechanism’s intricate workings has been a long and arduous journey. X-ray and CT scans have revealed layers of gears, inscriptions, and calendars, each piece contributing to its astronomical calculations. Researchers have painstakingly reconstructed the device, deciphering its inscriptions and piecing together its functions.

The Antikythera mechanism could predict solar and lunar eclipses, track the five known planets (Mercury, Venus, Mars, Jupiter, and Saturn), and even account for the moon’s elliptical orbit. It’s an incredible feat of engineering, far exceeding what was thought possible for its time.

The Antikythera mechanism is often considered to be the world’s oldest computer, or at least a precursor of modern computing. It demonstrates that the ancient Greeks had advanced knowledge of astronomy, mathematics, and engineering, and that they were able to create a mechanical model of the cosmos that could account for the irregularities of the planets’ orbits. The mechanism is also a testimony to the cultural and scientific achievements of the Hellenistic period, when Greek civilization spread across the Mediterranean and beyond.

That said, the creators of this sophisticated ancient device remain shrouded in the mists of time. Some experts point to Archimedes, the famed mathematician and inventor, for his known genius in engineering and astronomy. Others speculate it originated from Rhodes, a center of astronomy and home to Hipparchus, who developed theories reflected in the workings of the mechanism. While specific identification remains elusive, the intricate craftsmanship and advanced knowledge embedded within the mechanism hint at a society with impressive scientific and technological prowess, waiting to be rediscovered through further investigation and analysis.

Many other aspects of the Antikythera mechanism also remain unknown or controversial, despite decades of research and reconstruction efforts. Only about a third of the original device has survived, in 82 fragments that are severely damaged and corroded. Some of the gears are missing or incomplete, and some of the inscriptions are unreadable or ambiguous. Researchers have used various methods, such as X-ray analysis and 3D computer modelling, to try to piece together the puzzle and understand how the mechanism worked and what it looked like.

One of the latest attempts was made by a team of scientists from University College London (UCL), who published their findings in March 2021. They claimed to have solved the mystery of the front panel of the mechanism, which has been more elusive than the back panel (previous research has solved the mechanism’s rear part, but the nature of its complex gearing system at the front remained a mystery).

The team proposed a new arrangement of gears that could display the motion of the sun, moon, and planets on concentric rings, as well as indicate when they would rise and set in different geographic locations. By using rational approximations for synodic cycles characterized by small prime factors, such as 7 and 17, they managed to discover gears capable of being shared across the gear-trains associated with various planets. They claimed that their reconstruction matched all the physical evidence and the inscriptions on the mechanism.

Not everyone agrees with their interpretation, however. Some experts have criticized their use of an ancient Greek mathematical method called “exhaustion”, which they said was not suitable for designing gear ratios. Others have questioned their assumption that all the planets were aligned when the mechanism was set to zero position. Still others have pointed out that their reconstruction does not explain some features of the mechanism, such as a small sphere that represented Venus.

The debate over the Antikythera mechanism is likely to continue as new evidence and technologies emerge. The ultimate goal is not only to reveal how the device worked, but also to understand by whom and why it was made and what it meant for its creators and users. Was it a scientific instrument, an educational tool, a religious object, or something else? How was it related to other aspects of ancient Greek culture, such as philosophy, art, literature, and politics? How did it influence later developments in science and technology?

The Antikythera mechanism serves as a powerful reminder that our understanding of the past is constantly evolving. It beckons us to be open to new discoveries and push the boundaries of what we believe possible. This ancient “computer” continues to inspire awe and ignite the quest for knowledge, reminding us that the human spirit of exploration transcends time and technology.

Sources: 1, 2, 3