- Researchers believe they have solved the 2,200-year-old mystery of the Antikythera Mechanism.
- The ancient device, found in a shipwreck, probably followed the Greek lunar calendar.
- They used statistical modeling techniques typically used to study ripples in space-time.
Last year, Graham Woan knew exactly how he wanted to spend his Christmas holiday: he wanted to solve the 2,200-year-old mystery of the world’s oldest known ‘computer’.
The bronze device, known as the Antikythera Mechanism, is a mechanical computer with interlocking gears. In the second century BCE, a user would use the rings and evenly spaced holes to map out future celestial events, such as eclipses.
But how many of those evenly spaced holes there were is a mystery. And it is the key to understanding exactly how the computer works.
YouTuber Chris Budiselic has long been fascinated by the mechanism and began making his own version seven years ago, but wasn’t sure how many holes to put in it.
Based on a number of published studies by Budisic, astronomers from the University of Glasgow, including Woan, concluded To find the answer, they used statistical modeling techniques.
“It seemed like an interesting problem, and I thought I could solve it in a different way during the Christmas holidays. So I started working with statistical techniques to answer the question,” Woan said in a university press release.
Based on the number of holes, the researchers found that the device follows a lunar calendar rather than an Egyptian one, as previous research suggested.
A shipwreck full of ancient treasures
The Antikythera Mechanism is just one of the intriguing finds from a 2,000-year-old shipwreck first discovered by divers in 1900. Divers riding out a storm found the remains near the Greek island of Antikythera.
Excavations have unearthed three life-size marble horse statues, coins, jewelry and other treasures, according to the Woods Hole Oceanographic Institute. But the Antikythera Mechanism may be the most unique discovery of all.
About the size of a shoebox, it has broken into six pieces and has been eroded by its time underwater. The mechanism is so sophisticated that some thought it must be a modern device mixed in with the ancient artifacts, according to Derek John de Solla Price, who helped discover the device’s function in the 1970s.
X-ray images taken in 2005 gave researchers new details about the device. And in 2020, Budiselic and his colleagues used the images to measure the positions of the holes and suggested that the mechanism had between 347 and 367 holes. If it had had closer to 350 holes, it would have followed the lunar calendar. If it had had 365, it would have been modeled after the Egyptian calendar.
However, it was difficult to give an exact number as the device was in poor condition.
After hearing about Budiselic’s research, Woan first used Bayesian analysis, calculating various probabilities of the total number of holes based on the position and number of holes in the remaining bronze pieces. He learned that it was hundreds of times more likely that the device had 354 holes than 360 holes.
Woan’s colleague Joseph Bayley followed up the research by adapting techniques used to study gravitational waves, which are ripples in spacetime. His results agreed with Woan’s; there were probably 354 or 355 holes in the ring.
In other words, there is a much greater chance that the mechanism followed the Greek lunar year rather than the Egyptian one. It was able to calculate the positions of planets incredibly accurately for its time.
The find confirms the impressive craftsmanship and knowledge that went into making the device. “The precision of the positioning of the holes would have required very precise measuring methods and an incredibly steady hand to punch them,” Bayley said in the press release.
The two published their research in the peer-reviewed Horological Journal.