Antikythera mechanism revealed to track ancient Greek lunar calendar

The Antikythera Mechanism is an approximately 2,200-year-old analogue computer created in ancient Greece. The device, made of bronze and consisting of complex systems of gears, was once used for calculating the positions of celestial bodies and predicting astronomical events. It still holds many mysteries. Recently, researchers discovered that the computer tracked the Greek lunar calendar, contrary to previous beliefs that it followed the ancient Egyptian calendar.

Divers found the Antikythera Mechanism in 1901 off the coast of the Greek island of Antikythera. They reached an ancient merchant ship at a depth of 42 metres. They recovered numerous statues, and the device is now considered the world's oldest computer. In 1902, archaeologist Valerios Stais determined that the mechanism contained 37 bronze gears, ranging from 1 centimetre to 17 centimetres in diameter. They were driven by a hand crank on the side and moved several pointers.

Initially, researchers thought it was an ancient clock, but it became a much more advanced device. The Antikythera Mechanism, the shoebox-size, was formerly used to observe the movements of the Sun, Moon, and planets, synchronize the solar calendar with the lunar calendar, or predict solar and lunar eclipses. At first, experts believed that the Antikythera Mechanism tracked the solar clock used by the Egyptians, but the latest research indicates it was the Greek lunar calendar, reports Live Science.

In 2020, a team led by independent researcher Chris Budiselic, using new X-ray images, measurements, and mathematical analysis, determined that the mechanism likely did not cover a full solar year but 354 days, as in the lunar calendar. Further research, published on 27th June of this year in "The Horological Journal" by a team from the University of Glasgow, confirmed these findings.

In the latest analyses of the Antikythera Mechanism, statistical techniques developed for the Laser Interferometer Gravitational-Wave Observatory (LIGO) to detect gravitational waves were employed. These methods allowed for identifying the number and distribution of missing holes in the calendar ring. It was ultimately determined that the mechanism likely had 354 or 355 holes, indicating that it tracked the lunar calendar used in ancient Greece.

"The results from the Glasgow team provide new evidence that one of the components of the Antikythera Mechanism most likely served to track the Greek lunar year," the researchers stated in a release. Graham Woan, co-author of the study, emphasised the precision of the holes, which required very accurate measuring techniques and an extremely steady hand.