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Ancient Greek Computer Reconstructed
afaik_ianal writes "A working reconstruction of an ancient Greek computer, the Antikythera mechanism, which was found at the bottom of the ocean in 1900 has been unveiled and is on display at the Technopolis museum, in Athens. The device is believed to have been used to calculate the positions of various celestial bodies including the sun and the moon on any given date. While some guesswork was required in the reconstruction, the bulk of the design is based on updated X-ray photographs of the device."
I saw a documentary on this on the Discovery channel at least a 100 years ago. I suppose now its just "traveling". They have had this thing running for a while.
Here's the text:
The Antikythera mechanism
The clockwork computer
Sep 19th 2002
From The Economist print edition
An ancient piece of clockwork shows the deep roots of modern technology
WHEN a Greek sponge diver called Elias Stadiatos discovered the wreck of a cargo ship off the tiny island of Antikythera in 1900, it was the statues lying on the seabed that made the greatest impression on him. He returned to the surface, removed his helmet, and gabbled that he had found a heap of dead, naked women. The ship's cargo of luxury goods also included jewellery, pottery, fine furniture, wine and bronzes dating back to the first century BC. But the most important finds proved to be a few green, corroded lumps--the last remnants of an elaborate mechanical device.
The Antikythera mechanism, as it is now known, was originally housed in a wooden box about the size of a shoebox, with dials on the outside and a complex assembly of bronze gear wheels within. X-ray photographs of the fragments, in which around 30 separate gears can be distinguished, led the late Derek Price, a science historian at Yale University, to conclude that the device was an astronomical computer capable of predicting the positions of the sun and moon in the zodiac on any given date. A new analysis, though, suggests that the device was cleverer than Price thought, and reinforces the evidence for his theory of an ancient Greek tradition of complex mechanical technology.
Michael Wright, the curator of mechanical engineering at the Science Museum in London, has based his new analysis on detailed X-rays of the mechanism using a technique called linear tomography. This involves moving an X-ray source, the film and the object being investigated relative to one another, so that only features in a particular plane come into focus. Analysis of the resulting images, carried out in conjunction with Allan Bromley, a computer scientist at Sydney University, found the exact position of each gear, and suggested that Price was wrong in several respects.
In some cases, says Mr Wright, Price seems to have "massaged" the number of teeth on particular gears (most of which are, admittedly, incomplete) in order to arrive at significant astronomical ratios. Price's account also, he says, displays internal contradictions, selective use of evidence and unwarranted speculation. In particular, it postulates an elaborate reversal mechanism to get some gears to turn in the right direction.
Since so little of the mechanism survives, some guesswork is unavoidable. But Mr Wright noticed a fixed boss at the centre of the mechanism's main wheel. To his instrument-maker's eye, this was suggestive of a fixed central gear around which other moving gears could rotate. This does away with the need for Price's reversal mechanism and leads to the idea that the device was specifically designed to model a particular form of "epicyclic" motion.
The Greeks believed in an earth-centric universe and accounted for celestial bodies' motions using elaborate models based on epicycles, in which each body describes a circle (the epicycle) around a point that itself moves in a circle around the earth. Mr Wright found evidence that the Antikythera mechanism would have been able to reproduce the motions of the sun and moon accurately, using an epicyclic model devised by Hipparchus, and of the planets Mercury and Venus, using an epicyclic model derived by Apollonius of Perga. (These models, which predate the mechanism, were subsequently incorporated into the work of Claudius Ptolemy in the second century AD.)
A device that just modelled the motions of the sun, moon, Mercury and Venus does not make much sense. But if an upper layer of mechanism had been built, and lost, these extra gears could have modelled the motions of the three other planets known at the time--Mars, Jupiter and Saturn. In other words, the device may have been able to predict the positions of the known celestial bodies for any given date with a respectable degree of accuracy, usin
(notice the date, not quite "news")
The Antikythera mechanism
The clockwork computer
Sep 19th 2002
From The Economist print edition
An ancient piece of clockwork shows the deep roots of modern technology
WHEN a Greek sponge diver called Elias Stadiatos discovered the wreck of a cargo ship off the tiny island of Antikythera in 1900, it was the statues lying on the seabed that made the greatest impression on him. He returned to the surface, removed his helmet, and gabbled that he had found a heap of dead, naked women. The ship's cargo of luxury goods also included jewellery, pottery, fine furniture, wine and bronzes dating back to the first century BC. But the most important finds proved to be a few green, corroded lumps--the last remnants of an elaborate mechanical device.
The Antikythera mechanism, as it is now known, was originally housed in a wooden box about the size of a shoebox, with dials on the outside and a complex assembly of bronze gear wheels within. X-ray photographs of the fragments, in which around 30 separate gears can be distinguished, led the late Derek Price, a science historian at Yale University, to conclude that the device was an astronomical computer capable of predicting the positions of the sun and moon in the zodiac on any given date. A new analysis, though, suggests that the device was cleverer than Price thought, and reinforces the evidence for his theory of an ancient Greek tradition of complex mechanical technology.
Michael Wright, the curator of mechanical engineering at the Science Museum in London, has based his new analysis on detailed X-rays of the mechanism using a technique called linear tomography. This involves moving an X-ray source, the film and the object being investigated relative to one another, so that only features in a particular plane come into focus. Analysis of the resulting images, carried out in conjunction with Allan Bromley, a computer scientist at Sydney University, found the exact position of each gear, and suggested that Price was wrong in several respects.
In some cases, says Mr Wright, Price seems to have "massaged" the number of teeth on particular gears (most of which are, admittedly, incomplete) in order to arrive at significant astronomical ratios. Price's account also, he says, displays internal contradictions, selective use of evidence and unwarranted speculation. In particular, it postulates an elaborate reversal mechanism to get some gears to turn in the right direction.
Since so little of the mechanism survives, some guesswork is unavoidable. But Mr Wright noticed a fixed boss at the centre of the mechanism's main wheel. To his instrument-maker's eye, this was suggestive of a fixed central gear around which other moving gears could rotate. This does away with the need for Price's reversal mechanism and leads to the idea that the device was specifically designed to model a particular form of "epicyclic" motion.
The Greeks believed in an earth-centric universe and accounted for celestial bodies' motions using elaborate models based on epicycles, in which each body describes a circle (the epicycle) around a point that itself moves in a circle around the earth. Mr Wright found evidence that the Antikythera mechanism would have been able to reproduce the motions of the sun and moon accurately, using an epicyclic model devised by Hipparchus, and of the planets Mercury and Venus, using an epicyclic model derived by Apollonius of Perga. (These models, which predate the mechanism, were subsequently incorporated into the work of Claudius Ptolemy in the second century AD.)
A device that just modelled the motions of the sun, moon, Mercury and Venus does not make much sense. But if an upper layer of mechanism had been built, and lost, these extra gears could have modelled the motions of the three other planets known at the time--Mars, Jupiter and Saturn. In other words, the device may have been able to predict the positions of the known celestial bodies for any given date with a respectable degre
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Has anyone else noticed that the Economist article linked is from 2002?
It's a single-problem solving analog computer of the classic, pre-Turing sense. They used to have all kinds of crap like this for solving various problems. Easier (at the time) (and probably cooler) than a book filled with lists. Not a Turing complete machine by any sense... more like the ABC device that people are always claiming was the "first computer," than an ENIAC.
Dude, I think I can see my house from here.
It isn't a computer, though.
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
This clockwork planetary displaying device is (today) properly called an orrery, although it predates the Earl of Orrery by about 18 centuries. It also predates the astrolabe by about a thousand years, too.
Not that you can't use an orrery to occasionally tell the date, but much of the time you won't have enough information to get a valid reading. It's completely useless during the day, and even at night some of the planets are usually "too near" the sun to be visible. Occasionally, the planetary alignment is such that none of the "visible" planets can be seen for weeks at a time.
Also note that an orrery doesn't necessarily provide "altitude" information. I'm unaware of any hand-held clockwork orreries that do (including modern ones.) While you can base the date on azimuth readings of the planets, many of them move so slowly across the night sky that it could be difficult to make an accurate reading; especially with the tools of 87 B.C. The fixed stars are much easier to locate, and altitude is much, much easier to read than azimuth (gravity is a much easier reference to use than some concept of north.)
John
Ancient Greeks (I am Greek) had built complete moving planetaria from before 212 BCE. They had the knowledge and the technology to predict and actually show the movements of all planets they knew about. Ancient Greeks also had simple small steam engines and pumps.
There was no Greek empire - ever. There was an Athenian empire, but that never controlled all of the Greek city-states. Many of the Greek city-states maintained some degree of autonomy under the Macedonians, Roman Republic, and early Empire. Augustus himself confirmed Athens' autonomy (not independence, mind you, but autonomy - the Roman imperial administration didn't start interfering with internal issues until Caligula, I suspect). The Greeks considered themselves Greeks (and the Romans considered them Greeks) for at least 250 years after the fall of Corinth (in 146, yes) and Syracuse (in 212 BCE; remember Archimedes?). In the later empire and through until the fall of Constantinople to the Turks, they considered themselves romaioi - which is Greek for "Roman." So describing this as a Greek calculating mechanism is perfectly valid. (But no, it is not a computer.)
http://www.21stcenturysciencetech.com/articles/Spr ing03/Antikythera.html