New research into ripples in the fabric of space-time suggests that a nearly 2,000-year-old cosmic calculator followed the lunar calendar instead of the solar one.
The hand-powered Antikythera Mechanism was recovered in pieces from a shipwreck in the Aegean Sea in 1901, sparking more than a century of research into how the device came to be – and why. The box-shaped mechanical computer used gears and numbers to track ancient astronomical events such as solar eclipses and planetary movements.
Now, researchers are using recent work surrounding gravitational waves, which are ripples in spacetime caused by events such as black hole mergers or collisions between stars, to help unravel the mechanics of the ancient Greek gears of Antikythera . (The device is named after the Greek island near where it was found.)
“It has given me a new appreciation for the Antikythera mechanism and the work and care that Greek craftsmen took to make it – the accuracy of the hole positioning would have required very precise measuring techniques and an incredibly steady hand to strike them ,” the study. Co-author Joseph Bayley, a research associate in the department of physics and astronomy at the University of Glasgow, said in a statement.
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The new study builds on previous research in 2021 that used X-rays to show “fresh details of regularly spaced holes” under one of the mechanism’s broken rings, the statement said. Known as a “calendar ring,” this section is labeled with the names of the ancient Egyptian months inscribed in ancient Greek, according to the British Horological Institute.
Computerized X-ray images “also revealed inscriptions describing the movements of the sun, moon and five planets known in antiquity and how they appeared in the foreground like an ancient Greek cosmos,” the year-old study said. 2021, published in Nature.
That 2021 study also noted the interdisciplinary nature of the Antikythera mechanism: “Solving this complex 3D puzzle reveals a genius creation—combining cycles from Babylonian astronomy, mathematics from Plato’s Academy, and ancient Greek astronomical theories.”
The new study, in the Horological Journal, suggests that researchers can predict how many holes there were in the calendar ring using statistical models derived, in part, from the search for gravitational waves. Rooster found that the calendar ring likely contained 354 holes, following a lunar year of 354 days (or 12 waxing and waning cycles of the moon). Unlike the 365-day solar year that most of the world uses today, the Ancient Egyptian calendar followed the lunar year, as does the Islamic calendar that is still widely used around the world.
The team also took inspiration from YouTuber and machinist Chris Budiselic’s Clickspring channel. Budiselic has built a replica of the Antikythera Mechanism while conducting independent research. Budiselic’s team suggested that the ring may contain anywhere between 347 and 367 holes.
One form of analysis, led by Glasgow astrophysics professor Graham Woan, came from Bayesian statistics. This “uses probability to quantify uncertainty based on incomplete data,” the statement said.
The rest, from the gravitational wave search led by Bayley, was fitted by statistics used with data from LIGO (Laser Interferometer Gravitational-Wave Observatory) which looks for ripples in space-time. (Woan is also a LIGO researcher.)
Both statistical studies independently suggested that the ring has either 354 or 355 holes. Previous studies had suggested that the lunar calendar was more important to the creators of the Antikythera Mechanism, but the new study “highly increases the likelihood that this was the case,” Bayley said in the statement.
“It’s a neat symmetry,” Woan added, “that we’ve adapted the techniques we use to study the universe today to understand more about a mechanism that helped people keep track of the heavens nearly two millennia ago.”