Gravitational wave experts discover ‘remarkable’ secrets of ancient computers

Special techniques to study ripples in the universe may have helped researchers solve an age-old mystery.

Statistical modeling methods developed to study gravitational waves have been used to predict the structure of a broken piece of a millennia-old artifact, according to a new paper in The Horological Journal.

These techniques allowed researchers to determine how many holes there were in one of the broken rings of the Antikythera mechanism, the ancient computer that was built in Indiana Jones and the Dial of Destiny.

The Antikythera Mechanism is an ancient Greek analog device dating back to between 100 and 200 BC and is considered the world’s first known computer. Discovered in 1901 in a shipwreck off the coast of the Greek island of Antikythera, the device is believed to have been used to predict astronomical positions and eclipses for calendrical and astrological purposes.

The mechanism consists of a complex system of bronze gears and dials, housed in a wooden case. It has 30 gears, which is an incredibly advanced design for its time.

Its complexity suggests that the ancient Greeks had an advanced knowledge of gear technology, much more sophisticated than previously thought.

Modern imaging techniques, such as X-ray computed tomography, have been used to study the mechanism’s internal structure and functions. It has slowly become apparent that it was used to calculate the locations of planets, predict eclipses, and keep track of months and years.

Thanks to X-rays in 2020, it was discovered that one of the device’s rings had evenly spaced holes. Because the ring was broken, it was unclear how many rings it originally had, but researchers estimate between 347 and 367.

According to the new paper, it is likely that the ring had 354 holes, which corresponds to the lunar cycle. According to their calculations, the probability of the ring having 354 holes is hundreds of times greater than the probability of the ring having 360 holes.

“We present a new analysis of the positions of holes under the calendar ring of the Antikythera mechanism,” the researchers wrote in the paper. “We significantly refine their estimate for the number of holes present in the entire ring. Our 68 percent credible estimate for this number, taking into account all the data, is 355.24 [plus or minus about 1.4].

“If holes adjacent to fractures are removed from the analysis, our estimate becomes 354.08. A ring of 360 holes is strongly discouraged, and any one of the 365 holes is not plausible given our model assumptions.”

This mystery was solved using similar statistical modeling techniques to those used to study gravitational waves, which are ripples in spacetime created by the motion of massive objects moving outward from the source.

“Towards the end of last year, a colleague pointed me to data collected by YouTuber Chris Budiselic. He wanted to make a replica of the calendar ring and was investigating ways to determine how many holes it had,” Graham Woan, a co-author of the paper and a professor at the University of Glasgow’s School of Physics & Astronomy, said in a statement.

“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.”

After the scientists applied this technique, they found that the number of holes was likely 354 or 355.

“Previous studies suggested that the calendar ring probably followed the lunar calendar, but the dual technique we applied in this study increases the likelihood that this is indeed the case,” co-author Joseph Bayley, also a researcher at the University of Glasgow, said in the statement.

“It has given me a new appreciation for the Antikythera mechanism and the work and care that Greek craftsmen put into its making. The precision of the placement of the holes requires very precise measuring methods and an incredibly steady hand to punch them.”

While we will never know for sure how many holes the ring actually had, the analysis provides strong evidence that there were 354.

“It’s a nice symmetry that we’ve adapted the techniques we use today to study the universe to understand more about a mechanism that allowed people to track the sky almost 2,000 years ago,” Woan said.

“We hope that our findings about the Antikythera mechanism, while less supernaturally spectacular than those of Indiana Jones, will enhance our understanding of how this remarkable device was made and used by the Greeks.”

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