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ANTIKYTHERA Mechanism

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Author Topic: ANTIKYTHERA Mechanism  (Read 3880 times)
Bianca
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« Reply #30 on: August 15, 2008, 08:57:42 pm »








Similar devices in ancient literature



Cicero's De re publica, a 1st century BC philosophical dialogue, mentions two machines that function as a planetarium or orrery, predicting the movements of the Sun, the Moon, and the five planets.

The first device was built by Archimedes and brought to Rome by the Roman general Marcus Claudius Marcellus after the death of Archimedes at the siege of Syracuse in 212 BC. Marcellus had a high respect for Archimedes and this was the only item he kept from the siege. The device was kept as a family heirloom, and Cicero was shown it by Gallus about 150 years later. Gallus gave a 'learned explanation' of it and demonstrated it for Cicero.

"Hanc sphaeram Gallus cum moveret, fiebat ut soli luna totidem conversionibus in aere illo quot diebus in ipso caelo succederet, ex quo et in [caelo] sphaera solis fieret eadem illa defectio, et incideret luna tum in eam metam quae esset umbra terrae, cum sol e regione."

When Gallus moved the globe, it happened that the Moon followed the Sun by as many turns on that bronze [contrivance] as in the Earth itself, from which also in the sky the Sun's globe became [to have] that same eclipse, and the Moon came then to that position which was [its] shadow [on] the Earth, when the Sun was in line.



Pappus of Alexandria stated that Archimedes had written a now lost manuscript on the construction of these devices entitled On Sphere-Making.

The surviving texts from the Library of Alexandria describe many of his creations, some even containing simple blueprints. One such device is his odometer, the exact model later used by the Romans to place their mile markers (described by Vitruvius, Heron of Alexandria and in the time of Emperor Commodus)The blueprints in the text appeared functional, but attempts to build them as pictured had failed. When the gears pictured, which had square teeth, were replaced with gears of the type in the Antikythera mechanism, which were angled, the device was perfectly functional.

Whether this is an example of a device created by Archimedes and described by texts lost in the burning of the Library of Alexandria, or if it is a device based on his discoveries, or if it has anything to do with him at all, is debatable.

If Cicero's account is correct (and there is reason to doubt it), then this technology existed as early as the 3rd century BC. Archimedes' device is also mentioned by later Roman era writers such as Lactantius (Divinarum Institutionum Libri VII), Claudian (In sphaeram Archimedes), and Proclus (Commentary on the first book of Euclid's Elements of Geometry) in the 4th and 5th centuries.

Cicero also says that another such device was built 'recently' by his friend Posidonius, "... each one of the revolutions of which brings about the same movement in the Sun and Moon and five wandering stars [planets] as is brought about each day and night in the heavens..."



It is unlikely that either of these machines were the Antikythera mechanism found in the shipwreck, because both the devices mentioned by Cicero were located in Rome at least 50 years later than the estimated date of the shipwreck. So we know of three such devices. The modern scientists who have reconstructed the Antikythera mechanism also agree that it was too sophisticated to have been a one-off device.



It is probable that the Antikythera mechanism was not unique, as shown by Cicero's references to such mechanisms.

This adds support to the idea that there was an ancient Greek tradition of complex mechanical technology that was later transmitted to the Islamic world, where similarly complex mechanical devices were built by Muslim engineers and astronomers during the Middle Ages.

In the early 9th century, the Banū Mūsā's Kitab al-Hiyal (Book of Ingenious Devices), commissioned by the Caliph of Baghdad, describes over a hundred mechanical devices, some of which may date back to ancient Greek texts preserved in monasteries. Similarly complex astronomical instruments were constructed by al-Biruni and other Muslim astronomers from the 11th century.

Such knowledge could have yielded to or been integrated with European clockmaking and medieval cranes.



FROM

http://en.wikipedia.org/wiki/Antikythera_mechanism
« Last Edit: August 15, 2008, 11:41:28 pm by Bianca » Report Spam   Logged

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