Sorry for being off the grid the last couple days, I have had a stomach virus and have not been well. But now for Man-Made Mystery Monday! The Antikythera mechanism was discovered in 45 meters of water in the Antikythera shipwreck off Point Glyphadia on the Greek island of Antikythera. The wreck was found in April 1900 by a group of Greek sponge divers, who retrieved numerous artifacts, including bronze and marble statues, pottery, unique glassware, jewelry, coins, and the mechanism. All were transferred to the National Museum of Archaeology in Athens for storage and analysis. Merely a lump of corroded bronze and wood at the time, the mechanism went unnoticed for two years while museum staff focused on more attractive new finds. On 17 May 1902, archaeologist Valerios Stais was examining the finds and noticed that one of the pieces of rock had a gear wheel embedded in it. Stais initially believed it was an astronomical clock, but most scholars considered the device to be prochronistic, too complex to have been constructed during the same period as the other pieces that had been discovered. Investigations into the object were soon dropped until Derek J. de Solla Price became interested in it in 1951. In 1971, both Price and a Greek nuclear physicist named Charalampos Karakalos made X-ray and gamma-ray images of the 82 fragments. Price published an extensive 70-page paper on their findings in 1974. It is not known how the mechanism came to be on the cargo ship, but it has been suggested that it was being taken to Rome, together with other treasure looted from the island, to support a triumphal parade being staged by Julius Caesar. In the late 2000s, findings of The Antikythera Mechanism Research Project suggest the concept for the mechanism originated in the colonies of Corinth, since some of the astronomical calculations seem to indicate observations that can be made only in the Corinth area of ancient Greece. Syracuse was a colony of Corinth and the home of Archimedes, which might imply a connection with the school of Archimedes. Another theory suggests that coins found by Jacques Cousteau in the 1970s at the wreck site date to the time of the devices construction, and posits its origin may have been from the ancient Greek city of Pergamon, home of the famous Library of Pergamum. With its many scrolls of art and science, it was second in importance only to the Library of Alexandria during the Hellenistic period. The ship carrying the device also contained vases in the Rhodian style, leading to a hypothesis the device was constructed at an academy founded by the Stoic philosopher Posidonius on that Greek island. A busy trading port in Antiquity, Rhodes was also a center of astronomy and mechanical engineering, home to the astronomer Hipparchus, active from about 140 BC to 120 BC. That the mechanism uses Hipparchuss theory for the motion of the moon suggests the possibility he may have designed, or at least worked on it. On the front face of the mechanism there is a fixed ring dial representing the ecliptic, the twelve zodiacal signs marked off with equal 30 degree sectors. This matched with the Babylonian custom of assigning one twelfth of the ecliptic to each zodiac sign equally, even though the constellation boundaries were variable. Outside of that dial is another ring which is rotatable, marked off with the months and days of the Sothic Egyptian calendar, twelve months of 30 days plus five intercalary days. The months are marked with the Egyptian names for the months transcribed into the Greek alphabet. The first task, then, is to rotate the Egyptian calendar ring to match the current zodiac points. The Egyptian calendar ignored leap days, so it advanced through a full zodiac sign in about 120 years. The mechanism was operated by turning a small hand crank (now lost) which was linked via a crown gear to the largest gear. This moved the date pointer on the front dial, which would be set to the correct Egyptian calendar day. The year is not selectable, so it is necessary to know the year currently set, or by looking up the cycles indicated by the various calendar cycle indicators on the back in the Babylonian ephemeris tables for the day of the year currently set, since most of the calendar cycles are not synchronous with the year. The crank moves the date pointer about 78 days per full rotation, so hitting a particular day on the dial would be easily possible if the mechanism was in good working condition. The action of turning the hand crank would also cause all interlocked gears within the mechanism to rotate, resulting in the simultaneous calculation of the position of the Sun and Moon, the moon phase, eclipse, and calendar cycles, and perhaps the locations of planets After the knowledge of this technology was lost at some point in Antiquity, technological artifacts approaching its complexity and workmanship did not appear again in Europe until the development of mechanical astronomical clocks in the fourteenth century.
Posted on: Tue, 13 Jan 2015 02:58:41 +0000
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