The Antikythera Mechanism is a multi-part device recovered from a shipwreck near the Greek island of Antikythera in 1901. It is believed to be the remains of a complex mechanical calculator from ancient times and has undergone considerable scrutiny and analysis to determine its true form and function. In a new study, astronomers from the University of Glasgow have used statistical modelling techniques developed to analyse gravitational waves to identify the location of a hole under the Antikythera Mechanism's calendar ring. Their results provide new evidence that the component was likely used to track the Greek lunar calendar.
Fragment of the Antikythera Mechanism. Image credit: National Archaeological Museum of Athens / CC BY-SA 3.0.
The Antikythera shipwreck is a Roman shipwreck dating back to the 1st century BC (85-50 BC).
It is located at the junction of the Aegean and Mediterranean Seas, east of the Greek island of Antikythera, near Crete.
The Antikythera ships are thought to have been carrying looted treasure from the coast of Asia Minor to Rome in support of a planned triumphal parade for Julius Caesar.
The wreck was discovered in 1900 by a group of Greek sponge diggers on their way to Tunisia, who had taken refuge from a storm near the island and decided to look for sponges while waiting for calmer weather.
Early excavations at the site produced a wealth of finds that are today housed in the National Archaeological Museum in Athens, Greece, including three life-size marble horses, jewels, coins, glassware, and hundreds of works of art, including a statue of Hercules.
The most surprising find was the corroded remains of a complex device known as the Antikythera Mechanism, which is thought to have been an early analog computer used to plan important events such as religious ceremonies, the early Olympic Games and agricultural activities.
Also known as the first mechanical computer, this bronze device was created between 150 and 100 B.C.
It was originally housed in a wooden case with overall dimensions of 31.5 x 19 x 10 cm, with doors at the front and back and much of the exterior covered with astronomical inscriptions.
The surviving fragments contain 30 gears in an incredibly complex arrangement – technological artifacts of similar complexity would not appear until 1,000 years later.
In 2020, new X-ray images of one of the rings in the mechanism, known as the calendar ring, revealed new details about the regular rows of holes underneath the ring.
However, because the ring was broken and incomplete, it was unclear how many holes it originally had.
Initial analysis by Antikythera researcher Chris Budicelic and his colleagues suggests it probably dates to between 347 and 367 B.C.
Above: The 82 surviving fragments of the Antikythera Mechanism. Image courtesy of T. Freeth others2006. Below: Reconstruction of the Antikythera Mechanism by Alan Bromley and Frank Percival. Image courtesy of Alan Bromley.
In the new study, University of Glasgow researchers Graham Warne and Joseph Bayley used two statistical analysis methods to uncover new details about the calendar wheel.
The study found that it was far more likely that the ring had 354 holes corresponding to the lunar calendar, rather than 365 holes according to the Egyptian calendar.
The analysis also shows that the presence of 354 holes is hundreds of times more likely than a ring with 360 holes, which previous studies have suggested as a possible number.
“Late last year a colleague pointed me to some data available from YouTuber Chris Budiselic, who was trying to make a replica calendar ring and was researching ways to work out how many holes there are in the ring,” Prof Warne said.
“I thought this was an interesting problem and thought there might be a different way to solve it over the Christmas holidays, so I set out to answer the question using statistical methods.”
Using a technique called Bayesian analysis, which uses probability to quantify uncertainty based on incomplete data, Professor Warne used the positions of the remaining holes and the arrangement of the ring's six remaining fragments to calculate an estimated number of holes in the mechanism.
His findings provided strong evidence that the mechanism's calendar ring contained either 354 or 355 holes.
At the same time, Dr Bailey had also heard about the problem, and he was applying techniques used by his group to probe the calendar ring by analysing signals picked up by the LIGO gravitational wave detectors, which measure tiny ripples in space-time caused by massive astronomical events such as colliding black holes passing through Earth.
The Markov Chain Monte Carlo and nested sampling methods used by Professor Warne and Dr Bailey provided a comprehensive set of probabilistic results, again suggesting that the ring most likely contained 354 or 355 holes within a circle of radius 77.1mm, with an uncertainty of approximately 1/3mm.
They also found that the holes were precisely positioned with exceptional precision, with the average radius variation between each hole being just 0.028mm.
“Previous studies had suggested that the calendar ring was likely lunar based, but the dual techniques we applied in this study make it much more likely that this was the case,” Dr Bailey said.
“It gave me a new appreciation for the Antikythera Mechanism and the effort and care that Greek artisans put into creating it. Getting the holes exactly where they were would have required extremely precise measuring techniques and an incredibly steady hand to drill them.”
“This is a fascinating symmetry that allows us to apply techniques used to study the universe today to better understand the mechanisms that helped people around 2,000 years ago to understand the movements of celestial bodies,” Prof Warne said.
“While our discoveries about the Antikythera Mechanism are not as supernaturally spectacular as the Indiana Jones mechanism, we hope they will help us better understand how this incredible device was built and used by the Greeks.”
a paper A paper on the findings was published in the July 2024 issue. Watch Journal.
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Graham Warne & Joseph Baillie. 2024. The number of holes in the Antikythera Mechanism’s improved calendar ring: a new analysis. Watch Journal
This article has been adapted from an original release from the University of Glasgow.
Source: www.sci.news
