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),