Researchers at UCL have solved an important piece of the puzzle that makes up the ancient Greek astronomical calculator known as the Antikythera mechanism, a hand-powered mechanical device used to predict astronomical events.
Known to many as the world’s first analog computer, the antikythera mechanism is the most complex piece of engineering left from the ancient world. The 2,000-year-old device was used to predict the positions of the sun, moon, and planets, as well as lunar and solar eclipses.
Published in Scientific reportsThe paper by the multidisciplinary UCL Antikythera Research Team reveals a new representation of the ancient Greek order of the universe (Cosmos), within a complex gear system at the front of the mechanism.
Lead author Professor Tony Freeth (UCL Mechanical Engineering) explained: “Ours is the first model that satisfies all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the Mechanism itself.
“The sun, moon and planets are depicted in an impressive feat of ancient Greek brilliance.”
The Antikythera Mechanism has caused both fascination and intense controversy since its discovery in a Roman era shipwreck in 1901 by Greek sponge divers near the small Mediterranean island of Antikythera.
The Astronomical Calculator is a bronze device made up of a complex combination of 30 leftover bronze gears used to predict astronomical events, including eclipses, phases of the moon, positions of the planets, and even dates of the Olympics.
While great strides have been made over the past century to understand how it worked, studies in 2005 using 3-D X-rays and surface imaging allowed researchers to show how the mechanism predicted eclipses and calculated the moon’s variable motion.
However, so far, a full understanding of the gear system at the front of the device has eluded researchers’ best efforts. Only about a third of the mechanism survived and was split into 82 fragments – posing a huge challenge to the UCL team.
The largest surviving fragment, known as fragment A, displays bearing, pillar and block features. Another, known as Fragment D, has an inexplicable disc, a 63-tooth gear and a plate.
Previous research had used X-ray data from 2005 to reveal thousands of text characters hidden within the fragments that had been unread for nearly 2,000 years. Inscriptions on the back contain a description of the cosmos image, with the planets moving on rings and indicated with marker beads. It was this display that the team tried to reconstruct.
Two critical numbers in the front X-rays, 462 years and 442 years, accurately depict the cycles of Venus and Saturn, respectively. When observed from Earth, the cycles of the planets sometimes reverse their movements against the stars. Experts must track these variable cycles over long periods of time to predict their positions.
“Classical astronomy of the first millennium BC originated in Babylon, but nothing in this astronomy suggested how the ancient Greeks found the very accurate 462-year cycle for Venus and 442-year cycle for Saturn,” said PhD student and UCL Antikythera Research Team. member Aris Dacanalis.
Using an ancient Greek mathematical method described by the philosopher Parmenides, the UCL team not only explained how the cycles for Venus and Saturn were derived, but also managed to restore the cycles of all other planets, where it evidence was lacking.
PhD candidate and team member David Higgon explains: “After much struggle, we managed to match the evidence in fragments A and D with a mechanism for Venus, which models exactly the 462-year planetary period relationship, using the 63-tooth gear. an important role.”
Professor Freeth added, “The team then 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.”
“This is a significant theoretical advance in the way the Kosmos was constructed in the Mechanism,” added co-author, Dr. Adam Wojcik (UCL Mechanical Engineering). “Now we have to prove its feasibility by making it with old techniques. A particular challenge will be the system of nested tubes carrying the astronomical output. “
Header Image Credit: Gary Todd – Public Domain