Researchers at UCL have recreated a mechanical Cosmos for the Antikythera Mechanism, known to many as the world’s first analogue computer.
The ancient Greek Antikythera Mechanism was used to predict the positions of the Sun, Moon and the planets as well as lunar and solar eclipses. Discovered in a Roman-era shipwreck in 1901 by divers near the Mediterranean island of Antikythera, the astronomical calculator has fascinated researchers ever since.
The hand-powered device consists of a complex combination of 30 surviving bronze gears used to predict astronomical events. Studies in 2005 using 3D X-rays and surface imaging enabled researchers to show how the mechanism predicted eclipses and calculated the variable motion of the moon, but a full understanding of the gearing system at the front of the device had so far eluded scientists’ efforts.
Published in Scientific Reports, the team’s findings are said to represent a significant advancement toward understanding the full capabilities of the Antikythera Mechanism. The paper reveals a new display of the ancient Greek order of the Universe (Cosmos).
“Ours is the first model that conforms to all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the mechanism itself,” said lead author Tony Freeth, professor of mechanical engineering at UCL. “The Sun, Moon and Planets are displayed in an impressive tour de force of ancient Greek brilliance.”
Only around a third of the mechanism has survived and is split into 82 fragments. The biggest surviving fragment, known as Fragment A, displays features of bearings, pillars and a block. Another, known as Fragment D, features an unexplained disk, 63-tooth gear and plate.
The 2005 data revealed thousands of text characters hidden inside the fragments, unread for nearly 2000 years. Inscriptions on the back cover include a description of the cosmos display, with the planets moving on rings and indicated by marker beads. The team worked to reconstruct this display.
Two critical numbers in the X-rays of the front cover, of 462 years and 442 years, accurately represent cycles of Venus and Saturn respectively. When observed from Earth, the plants’ cycles sometimes reverse their motions against the stars. Experts must track these cycles over long time-periods to predict their positions.
PhD candidate and team member Aris Dacanalis explained that the classic astronomy of the first millennium BC originated in Babylon, but that nothing in the astronomy suggested how the ancient Greeks found the highly accurate cycles for Saturn and Venus.
Using an ancient Greek mathematical method described by the philosopher Parmenides, the team has reportedly discovered how the cycles were derived, as well as recovering the cycles of all other planets where evidence was missing.
“After considerable struggle, we managed to match the evidence in Fragments A and D to a mechanism for Venus, which exactly models its 462-year planetary period relation, with the 63-tooth gear playing a crucial role,” said PhD candidate and team member David Higgon.
Professor Freeth explained that the team then created mechanisms for all of the planets that would calculate the new advanced astronomical cycles and minimise the number of gears in the whole system, so that they would fit into the tight spaces available.
“This is a key theoretical advance on how the Cosmos was constructed in the Mechanism,” added co-author, Dr Adam Wojcik (UCL Mechanical Engineering). “Now we must prove its feasibility by making it with ancient techniques. A particular challenge will be the system of nested tubes that carried the astronomical outputs.”
A video with further information can be found here.
Now that is what I call reverse engineering! The video is an eye opener to just what has been lost in history and also what was possible in ancient Greece.
Absolutely brilliant. The video is a must watch. Waiting with bated breath for the attempts to actually produce and machine the parts using techniques and tools available at the time! What other artifacts are there displaying such ingenuity yet to be found? Such technologies seem to have been lost and expunged once we got into Roman and subsequent times, where the rise of politics and religion imposed new norms of society, the effects of which are still felt today.
Incredible. Had to watch it again.
I too watched the video, very good . But why was the mechanism on a ship , was it just being transported or is it a navigational aid ?
Absolutely fantastic ! (bookmarked)
Difficult to believe so many first of a kind mechanisms in that one unit, or is it a collection of previously tried & tested principles put together for that specific requirement, if so what other marvels are hidden inside lumps of rubble ?
We really do stand on the shoulders of giants.
For something interesting to watch over breakfast I would like to suggest ‘Clickspring’ making a replica of the Antikythera Mechanism: https://www.youtube.com/channel/UCworsKCR-Sx6R6-BnIjS2MA
A delightful article and video. A lovely blend of archaeology, horology, astronomy and precision engineering. Something that every student in STEM should see! I look forward to reading about investigations into possible ways of making the nesting tubes using techniques of that period in ancient Greece. It has really made me think!
A working model has already been made and tested….saw it quite a while ago, obviously in same place as original is housed, in airtight conditions. Excellent recreation
Bit late?? Saw a working model ages ago, in Greece. Also video of it being built in England by team who worked out the complete plan and purposes being forecast
I was going to ask the same as commenter Stephen Pounder, why was it on a ship and I thought the same that maybe it helped with navigation. Then I wondered why do people spend all that time, money, and effort trying to figure it out and to rebuild it? Just out of curiosity? But, I also know how I can get obsessed over things I want to know. It was interesting, but a lot of it was over my head. What else did the ancients accomplish that we are unaware of? It is fascinating!
What is odd is that, if this tech is 2000 years old, why have we not found anything similar for example clocks of a similar age? It would have been a huge effort to build a one off.
Another amazing fact about this mechanism is that it is all based on observational astronomy done with the naked eye ! Think about that, here in our modern world where at many times it is almost impossible to see the stars and planets at night because of pollution from lighting and emissions.
I wonder where the mechanism actually originated ?
We know there was trade between the Mediterranean and Persia and probably India and China, all ancient civilisations that were much more advanced than any in Europe at that time.
Michael: The only clocks at that time, from what I recall, were water clocks – basically a water container that ‘leaks’ water at a controlled rate. To achieve a smaller portable clock like this mechanism would require some stored energy mechanism to drive it like a tensile steel spring – I believe, suitable technology didn’t exist at that point in time – the Bronze Age.
Another Steve, surely the fact that this piece did exist is proof that such technology could have existed. The device is approx. 2000 years old, iron age period 500BCE to 330BCE (depending on source) so iron was around, indeed the Romans new how to crudely temper steel for their Gladius.
Not insinuating anything, but it is odd that you are publishing this now. As an Austrailian has been, explained his findings, builting a functional replica, while showing the building process on YouTube & Patreon over the last 6 years, at the same time replicating tools and methods of the era for some of the construction, just finished the process of having his paper peer reviewed and it was recently accepted for publishing in the British Horological Institute’s Journal. See Clickspring ‘Antikythera Mechanism’ and ‘Tools glorious tools’ on youtube.
Perhaps it took so much effort to make in those days that only one was ever made! What would be even more interesting are the tools and foundry techniques they used 2000 years ago. Or perhaps it isn’t actually that old? Simple enough to machine brass nowadays but back then?