Apr 12, 2022 I Paul Seaburn

"Day Zero" for Starting the Ancient Greek Antikythera Mechanism May Have Been Found

The Antikythera mechanism is considered to be the world’s oldest analog computer – found in a shipwreck in 1901, it dates back to between 87 BCE and 205 BCE. While careful study has allowed modern scientists to model how it may have worked for the Greek scientists who invented it, one key component is missing … and it’s not a physical one. The Antikythera mechanism needs a “Day Zero” – a beginning date to calibrate its astrological calculations. The chances of finding “Day Zero” are no longer zero – a team of researchers thinks it has determined the kickoff date of the Antikythera mechanism.

“This work analyzes the phase correlation of the three lunar cycles and the Saros/Exeligmos cycle, after the study of the chapter About Exeligmos in Introduction to the Phenomena by Geminus. Geminus, refers that each Exeligmos cycle began on very specific and rare dates, when the Moon positioned at the points of the three lunar cycles beginning: New moon at Apogee and at the Node.”

Think of the Antikythera mechanism as a an ancient yet sophisticated astrological calculator.

Aristeidis Voulgaris of the Thessaloniki Directorate of Culture and Tourism in Greece is the lead author of the “Day Zero” exposé in the preprint journal arXiv Physics. Since it was found in 1901, researchers have attempted to identify and reassemble the corroded pieces – a seemingly impossible challenge with pieces missing, engravings worn off and no instruction book to follow. According to Ars Technica, one visible engraving on the back represents a 223-month cycle called a Saros – the cycle of time for the Sun, Moon, and Earth to return to their same positions. The Saros includes solar and lunar eclipses, and Voulgaris believed a solar eclipse occurred on “Day Zero.” But which one?

“The extremely large duration of the Annular Solar eclipse occurred on December 22 178BC (Saros series 58), marks the start of the Prominent Saros Cycle Apokatastasis. The next day, 23 December 178BC, the Winter Solstice started.”

Using Saros data from NASA, Voulgaris and his team looked for Saros cycles during the period of 87 BCE to 205 BCE. “Saros series 58” was one of them, and it became the likely choice when they saw that its kickoff solar eclipse was an extremely long one … and that mysterious (to the people at the time) solar event was followed the next day by the winter solstice – an event mentioned in an Antikythera mechanism engraving. Two events that close together would have been a reason for celebratory festivals … and the team found them.

“During these two neighboring dates, the celebration of the religious festival of Isia started in Egypt and the Hellenistic Greece.”

In fact, Voulgaris found more astronomical events in that time period: a new moon at apogee and the Sun entering into the constellation Capricorn. Based on that collection of related data, the team connected the dots and stars and named 22/23 December 178 BCE as “an ideal, functional and representative initial date, in order to calibrate the initial position of the Mechanism's pointers.”

Will using 22/23 December 178 BCE as “Day Zero” allow the most accurate models to emulate the movement of the Antikythera mechanism and prove its usefulness and brilliance as the oldest analog computer? Some researchers doubt it because the Saros period is not a highly accurate record of the lunar and solar cycles. In addition, other researchers using seemingly accurate data have put the “Day Zero” in the summer rather than winter. Voulgaris believes his date is the winner because the engraving on the mechanism specifically mentions the winter solstice.

Whatever Day Zero turns out to be, it’s a tribute to the inventors of the Antikythera mechanism that it fascinates scientists two millenniums later.

Paul Seaburn
Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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