By building a digital model of the antikythera mechanism, scientists have finally uncovered a key function of the ancient device, revealing a design that required serious advanced thinking.
The 2,000-year-old Antikythera mechanism, pulled from a shipwreck off the coast of Crete in 1901, has baffled scientists for decades. New Research published in Scientific Reports presents a hypothetical model of the astronomical instrument, which Tony Freeth, the lead author and a mechanical engineer at the University of College London, says it is the first to satisfy “all physical evidence and agree with the descriptions in the scientific inscriptions engraved on the Mechanism itself”, he said in one pronunciation
The hand-powered device is the oldest known analog astronomical computer, an early example of complex mechanical engineering. The device dates back to Ancient Greece and modeled astronomical phenomena and events, such as lunar and solar eclipses and the positions of the sun, moon, Mercury, Venus, Mars, Jupiter and Saturn.
Only one third of the Antikythera MThe mechanism has been restored and nothing comparable exists for comparison. The incomplete relic, with its 30 bronze gears and 82 individual fragments, has forced scientists to speculate about what it looked like, what it was used for, and how it worked.
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In 2016, scientists presented the results of decades of research into the relic. Using an X-ray scanner, scientists were able to document 3,500 characters of explanatory text – a kind of instruction manual – embedded in the device. Analysis of this text suggests that the Antikythera mechanism is not a real computer in the sense that it is not programmable. Rather, it was a machine designed to convey our place in the universe and prediction of celestial events such as lunar and solar eclipses.
Fragment A, the main part of the device, consists of bearings, pillars and a block, while Fragment D contains a disk whose purpose is unknown, a gear with 63 teeth and a plate. The aim of the new study was to gain a better understanding of the gear system at the front of the mechanism, which is largely lacking.
The inscriptions mentioned a cosmic mechanical screen in which the planets and the moon, represented by marker beads, moved on rings. As the authors write in their study, “no previous reconstruction has come close” to creating a model that actually meets this clear specification. To that end, the team made an effort to recreate this missing – and supposed – part of the Antikythera mechanism.
“Solving this complex 3D puzzle reveals a genius creation – a combination of cycles of Babylonian astronomy, math from Plato’s Academy and ancient Greek astronomical theories,” wrote the authors, including mechanical engineer Adam Wojcik, also from UCL.
Indeed, the ancient Babylonians recorded the movements of the planets, while the ancient Greek philosopher Parmenides developed a mathematical model to explain these movements.
Inscriptions on the device reported celestial cycles assigned to Venus at 462 years and Saturn at 442 years. The scientists associated these numbers with synodic cycles, which describe the length of time it takes for a celestial body to return to its original position relative to our perspective on Earth. These cycles were important to the ancient Greeks because of their geocentric view of the universe. When looking at the night sky, the planets sometimes seem to pause and swing back and forth as they – and we on Earth – orbit the sun (i.e. retrograde motion), in what is an optical illusion. (A a fantastic example of this can be seen here, in which the Moon appears to be receding It’s a funny fact that the word ‘planet’ comes from the Greek word for ‘wanderer’.
The Greeks believed that the planets revolved Earth, were amazed at these retrograde movements, and they figured out some rather complicated theories and mathematical explanations to make it all work, many of them flatwrong.
Looking at the Antikythera mechanism The researchers themselves realized that components in fragments A and D corresponded to the mechanical motions of Venus, “which precisely models the 462-year planetary period relationship, in which the 63-tooth gear plays a critical role,” said David Higgon, a doctoral student and co-author of the paper, in the UCL statement. The scientists then determined the cycles of the remaining planets, which they did using the ancient Greek formulas, and then incorporated these cycles into “very compact mechanisms, in accordance with the physical evidence,” the paper said.
All of this means that the Greeks, with their geocentric view of the cosmos, made it unnecessarily difficult to themselves in designing the Antikythera mechanism. Instead of showing the planets:represented by beads moving along concentric circles – moving in one some direction around the sun, them had to show that the planets swayed back and forth during their cycles as they moved Soil. Incredibly, this had to be done for each of the five planets, where the relative position of each must be accurate at all times. That is, assuming the machine worked that way.
Equipped with their calculations, the scientists then designed and digitally recreated them this monstrously complicated thingThe scientists “created innovative mechanisms for all planets that would compute the new advanced astronomical cycles and minimize the number of gears in the entire system so that they would fit in the tight spaces available,” Freeth said. Indeed, the gear arrangements could not be arbitrarily sized, as the supposed components had to fit inside the device, including spaces no greater than 25 millimeters deep.
A 30-minute film over this research, which shows how this model came about, can be seen at Vimeo
The simulated machine appears to be working, but simulated is the keyword. The authors are right to say that there is one more important step to be completed.
“Now we have to prove its feasibility by making it with old techniques,” Wojcik said. “A particular challenge will be the system of nested tubes carrying the astronomical output.”
Fun. It sounds like the team is about to embark on an experimental archeology, in which a real physical one model of the Antikythera Mechanism will be builtThe mind is surprised to think that we may have a hard time recreating this “creation of genius” some 2,000 years later, in what is a remarkable example of lost technology.