A post by Pat
Around 150 B.C., a Roman merchant ship sank off the coast of the Greek island Antikythera. Were it not for a storm at sea two thousand years later, we may never have discovered one of the greatest scientific achievements of the ancient world. In October, 1900, a team of sponge divers discovered the shipwreck while lingering off the coast of Antikythera for shelter. The salvage operation took about two years. It would take 100 years for modern science to understand the purpose of the machine and how it worked. Even then there was skepticism. We couldn’t believe it was possible for the Ancients to make such an exquisite machine.
The sponge divers retrieved several pieces of rock which appeared to have embedded gear wheels and dials. At first it was thought they were parts of a clock or a navigating device. The inscriptions indicated its use was related to astronomy. It took decades to clean away the corrosion residue. It wasn’t until 1955 that work to decipher the mechanism began in earnest. The breakthrough came in 2005 with advanced imaging techniques which revealed the beauty and complexity of this mechanical calculator of the cycles of the solar system.
The full function and beauty of the Antikythera device remained hidden until recent studies subjected it to more advanced imaging techniques. First, it was photographed using a technique that exposed the surfaces to varying lighting patterns. This created different levels of contrast that allowed the researchers to read far more of the inscribed Greek text than was previously possible. Then, x-ray imaging was used to create full 3-D computer models of the mechanism, which revealed for the first time some of the more complex and detailed gear interactions. The Greek National Archaeological Museum’s discovery of some boxes filled with 82 additional mechanism fragments added new information as well.
The findings, published in Nature, are probably best described as “mind blowing.” Devices with this level of complexity were not seen again for almost 1,500 years, and the Antikythera mechanism’s compactness actually bests the later designs. Probably built around 150 B.C., the Antikythera mechanism can perform a number of functions just by turning a crank on the side.
The true genius of the mechanism goes beyond even the complex calculations and craftsmanship of a mechanical calendar. For example, the ancients didn’t know that the moon has an elliptical orbit, so they didn’t know why it sometimes slowed or sped up as it moved through the zodiac. The mechanism’s creator used epicyclic gears, also known as planetary gears, with a “pin-and-slot” mechanism that mimicked this apparent shifting in the moon’s movement. This use of epicyclic gears is far ahead of what anyone suspected ancient technology was capable of.
The Antikythera Mechanism was back in the news recently because a team of engineers created a working model out of Lego. At first I thought this was a bit flippant as though boasting this is child’s play for us. Maybe their project tells us engineers are people blessed to never outgrow the wonder and curiosity of a child.
This is a virtual representation which I think is more suitable to appreciate the elegance of the machine. I recommend watching in full screen.
The Ancients were inspired by the heavens to build an exquisite machine that captured the complex relationship of time and events. We learn over time but we also forget over time. When unexpected miraculous gifts come to us we must pause and reflect.
For a fuller discussion see Scientific American’s 15 minute two-part video about the mechanism.