The Antikythera mechanism, an ancient shoebox-sized device used to track the motions of the sun, moon, and planets, has been revealed to follow the Greek lunar calendar, not the solar calendar used by the Egyptians, as previously thought. This groundbreaking discovery comes from new research utilizing advanced analytical techniques.
The Antikythera mechanism, found by sponge divers off the Greek island of Antikythera in 1901, dates back approximately 2,200 years. Often referred to as the world’s oldest computer, this intricate device contains bronze gears. One key component, known as the “calendar ring,” was used to track the days of the year, with one hole for each day. Although this ring has been known for some time, it’s only partially preserved, leaving the exact number of days it tracked unclear.
In 2020, a team led by independent researcher Chris Budiselic utilized new X-ray images of the device, alongside measurements and mathematical analysis, to determine that the mechanism likely didn’t cover a full solar calendar year but instead spanned 354 days, a characteristic of a lunar calendar. This conclusion was further corroborated by another paper published in The Horological Journal on June 27, 2023.
This second paper, authored by a team from the University of Glasgow, employed statistical techniques originally developed for the Laser Interferometer Gravitational-Wave Observatory (LIGO), which detects gravitational waves. These techniques are remarkably sensitive, capable of discerning faint signals from potentially noisy backgrounds. When applied to the Antikythera mechanism, these methods allowed researchers to analyze the positioning of known holes and the probable way the fragments fit together, deducing the number and placement of missing holes. Ultimately, they concluded that the mechanism likely had 354 or 355 holes, strongly suggesting adherence to the 354-day lunar calendar used in Greece at the time.
Prior to these findings, it was believed that the Antikythera mechanism might have used the 365-day Egyptian solar calendar, as it’s more precise than the lunar calendar. However, the new research convincingly demonstrates the device’s alignment with the Greek lunar calendar.
The researchers from the University of Glasgow were particularly impressed by the creators’ meticulous attention to detail. “The precision of the holes’ positioning would have required highly accurate measurement techniques and an incredibly steady hand to punch them,” stated study co-author , an astrophysics professor at the University of Glasgow. “It’s a neat symmetry that we’ve adapted 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.”
The findings have been met with praise from other researchers in the field. , a co-author of the 2020 paper, expressed enthusiasm, stating, “We are very happy that more scholars are now accepting and validating our findings.”
, a professor of software engineering at the Athens University of Economics and Business, who has studied the mechanism but was not involved in either paper, expressed similar appreciation. “The Antikythera mechanism is a gift that keeps on giving,” Spinellis stated. “Despite its severe corrosion and many missing elements, the application of increasingly sophisticated technologies and innovative cross-disciplinary analysis continues to provide impressive insights into this remarkable artifact.”
