Tag Archives: Antikythera Mechanism Research Project

Antikythera’s (a 2,000 year old computer) secrets unlocked?

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The Antikythera Mechanism is fascinating and a March 12, 2021 University College London (UCL) press release (also on EurekAlert) reveals the reason for the fascination before announcing the latest research into this ‘celestial’ object,

Known to many as the world’s first analogue computer, the Antikythera Mechanism is the most complex piece of engineering to have survived from the ancient world. The 2,000-year-old device was used to predict the positions of the Sun, Moon and the planets as well as lunar and solar eclipses.

Exploded model of the Cosmos gearing of the Antikythera Mechanism. ©2020 Tony Freeth.

Continuing on from the March 12, 2021 University College London (UCL) press release,

Published in Scientific Reports, the paper from the multidisciplinary UCL Antikythera Research Team reveals a new display of the ancient Greek order of the Universe (Cosmos), within a complex gearing system at the front of the Mechanism.

Lead author Professor Tony Freeth (UCL Mechanical Engineering) explained: “Ours is the first model that conforms to all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the Mechanism itself.

“The Sun, Moon and planets are displayed in an impressive tour de force of ancient Greek brilliance.”

The Antikythera Mechanism has generated both fascination and intense controversy since its discovery in a Roman-era shipwreck in 1901 by Greek sponge divers near the small Mediterranean island of Antikythera.

The astronomical calculator is a bronze device that consists of a complex combination of 30 surviving bronze gears used to predict astronomical events, including eclipses, phases of the moon, positions of the planets and even dates of the Olympics.

Whilst great progress has been made over the last century to understand how it worked, studies in 2005 using 3D X-rays and surface imaging enabled researchers to show how the Mechanism predicted eclipses and calculated the variable motion of the Moon.

However, until now, a full understanding of the gearing system at the front of the device has eluded the best efforts of researchers. Only about a third of the Mechanism has survived, and is split into 82 fragments – creating a daunting challenge for the UCL team.

The biggest surviving fragment, known as Fragment A, displays features of bearings, pillars and a block. Another, known as Fragment D, features an unexplained disk, 63-tooth gear and plate.

Previous research had used X-ray data from 2005 to reveal thousands of text characters hidden inside the fragments, unread for nearly 2,000 years. Inscriptions on the back cover include a description of the cosmos display, with the planets moving on rings and indicated by marker beads. It was this display that the team worked to reconstruct.

Two critical numbers in the X-rays of the front cover, of 462 years and 442 years, accurately represent cycles of Venus and Saturn respectively. When observed from Earth, the planets’ cycles sometimes reverse their motions against the stars. Experts must track these variable cycles over long time-periods in order to predict their positions.

“The classic astronomy of the first millennium BC originated in Babylon, but nothing in this astronomy suggested how the ancient Greeks found the highly accurate 462-year cycle for Venus and 442-year cycle for Saturn,” explained PhD candidate and UCL Antikythera Research Team member Aris Dacanalis.

Using an ancient Greek mathematical method described by the philosopher Parmenides, the UCL team not only explained how the cycles for Venus and Saturn were derived but also managed to recover the cycles of all the other planets, where the evidence was missing.

PhD candidate and team member David Higgon explained: “After considerable struggle, we managed to match the evidence in Fragments A and D to a mechanism for Venus, which exactly models its 462-year planetary period relation, with the 63-tooth gear playing a crucial role.”

Professor Freeth added: “The team then created innovative mechanisms for all of the planets that would calculate the new advanced astronomical cycles and minimize the number of gears in the whole system, so that they would fit into the tight spaces available.”

“This is a key theoretical advance on how the Cosmos was constructed in the Mechanism,” added co-author, Dr Adam Wojcik (UCL Mechanical Engineering). “Now we must prove its feasibility by making it with ancient techniques. A particular challenge will be the system of nested tubes that carried the astronomical outputs.”

h/t BBC (British Broadcasting Corporation) March 12, 2021 article about the Anitikythera Mechanism, which includes another image and an embedded video. The March 12, 2021 University College London (UCL) press release includes links to more information about the Antikythera Mechanism, the research, and Dr. Tony Freeth.

For the insatiably curious, I have an October 2, 2012 posting and an August 3, 2016 posting with what was the latest information at the time.

Here’s a link to and a citation for the latest paper,

A Model of the Cosmos in the ancient Greek Antikythera Mechanism by Tony Freeth, David Higgon, Aris Dacanalis, Lindsay MacDonald, Myrto Georgakopoulou & Adam Wojcik. Scientific Reports volume 11, Article number: 5821 (2021) DOI: https://doi.org/10.1038/s41598-021-84310-w Published 12 March 2021

This paper is open access and, as these things go, it’s fairly accessible reading, i.e., even someone like me who has no interest in astronomy can understand enough to enjoy the article.

Today’s post falls, thematically speaking, into similar territory as yesterday’s (March 16, 2021) posting where in addition to celebrating Urania Day I included information about astronomy and some of its history.

More about the Antikythera (an ancient computer)

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Since 2004, an international consortium has been attempting to decode the mechanism known as an Antikythera. Discovered at the beginning of the 20th century, it has puzzled and intrigued scientists ever since. Last mentioned here in an Oct. 2, 2012 posting, this update is based on a July 20, 2016 essay by Mike Edmunds for The Conversation website. First, here’s a brief overview (Note: A link has been removed),

When we talk of the history of computers, most of us will refer to the evolution of the modern digital desktop PC, charting the decades-long developments by the likes of Apple and Microsoft. What many don’t consider, however, is that computers have been around much longer. In fact, they date back millennia, to a time when they were analogue creations.

Today, the world’s oldest known “computer” is the Antikythera mechanism, a severely corroded bronze artefact which was found at the beginning of the 20th Century, in the remains of a shipwreck near the Mediterranean island of Antikythera. It wasn’t until the 1970s that the importance of the Antikythera mechanism was discovered, when radiography revealed that the device is in fact a complex mechanism of at least 30 gear wheels.

The mechanism has since been established as the first known astronomical calendar, a complex system which can track and predict the cycles of the solar system. Technically, it is a sophisticated mechanical “calculator” rather than a true “computer”, since it cannot be reprogrammed, but nonetheless an impressive artefact.

Edmunds is an emeritus professor at the University of Cardiff (Wales) and the lead academic on the Antikythera Mechanism Research Project.

He describes the mechanism as it is presently understood and includes the latest findings (Note: Links have been removed),

When first made, the mechanism was about the size of a shoe box, with dials on both its front and back faces. A handle or knob on the side of the box enabled the user to turn the trains of gears inside –- originally there were considerably more gears than the 30 that still survive. On the front, pointers showed where the sun and moon were in the sky, and there was a display of the phase of the moon. On the rear, dials displayed a 19-year cycle of lunar months, the 18.2 year Saros cycle of lunar and solar eclipses, and even a four-year cycle of athletic competitions including the Olympic games.

The inscriptions are thought to have been a description for the user of what it was they were viewing as they operated the mechanism. However, the newly published texts add more to what we know of the mechanism: they establish that the positions of the five planets known in antiquity were also shown – Mercury, Venus, Mars, Jupiter and Saturn.

The planets were displayed on the machine in a way that took account of their rather irregular “wanderings” about the sky. Such a display had been suspected, and the confirmation reinforces that this was a very sophisticated and quite complicated device. The actual gear trains needed for the display of the planets are missing – presumably lost in the shipwreck – but we know from the very ingenious way that the sun and moon drives are designed and constructed that the makers of the mechanism certainly had the skills necessary to make the planetary drive.

The newly uncovered inscriptions include passages about what stars were just becoming visible –- or about to be lost in the glare of the sun – at different times of year. The style of these passages is very close to that of a well-known astronomical text by Greek astronomer and mathematician Geminos from the first Century BC. Not only does this tie in perfectly with the presumed date of the shipwreck (around 60BC), but also the latitude – which is implied by stellar data to be mid-Mediterranean – which would fit nicely with the mechanism originating on the island of Rhodes, from where there is a contemporary historic record from the writer Cicero of such devices.

Apparently divers have returned to the site this year to see if they can find more parts to the Antikythera and , hopefully unlock more of its secrets. (h/t July 20, 2016 phys.org news item),