On average, due to epicyclic gearing causing accelerations and decelerations. The device was kept as a family heirloom, and Cicero has Philus (one of the participants in a conversation that Cicero imagined had taken place in a villa belonging to Scipio Aemilianus in the year 129 BC) saying that Gaius Sulpicius Gallus (consul with Marcellus's nephew in 166 BC, and credited by Pliny the Elder as the first Roman to have written a book explaining solar and lunar eclipses) gave both a "learned explanation" and a working demonstration of the device. Price published an extensive 70-page paper on their findings in 1974. [27], The knowledge of this technology was lost at some point in antiquity. [67] The inscriptions on each one of the four divisions are:[10][13], The Saros dial is the main lower spiral dial on the rear of the mechanism. He initially believed that 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. But as soon as Gallus had begun to explain, by his sublime science, the composition of this machine, I felt that the Sicilian geometrician must have possessed a genius superior to any thing we usually conceive to belong to our nature. Parker, Richard Anthony, "The Calendars of Ancient Egypt," (Chicago: University of Chicago Press, 1950). It has a computed modelled rotational period of exactly four years, as expected. The team retrieved numerous large artefacts, including bronze and marble statues, pottery, unique glassware, jewellery, coins, and the mechanism. [89] A documentary, The World's First Computer, was produced in 2012 by the Antikythera mechanism researcher and film-maker Tony Freeth. [85] In the Islamic world, Banū Mūsā's Kitab al-Hiyal, or Book of Ingenious Devices, was commissioned by the Caliph of Baghdad in the early 9th century AD. The modelled rotational period of the Exeligmos pointer is 19,756 days; the modern value is 19755.96 days. [20], The Exeligmos Dial is the secondary lower dial on the rear of the mechanism. [13] Syracuse was a colony of Corinth and the home of Archimedes, and the Antikythera Mechanism Research project argued in 2008 that it might imply a connection with the school of Archimedes. That is irrelevant to the question of whether that position was computed using a heliocentric or geocentric view of the Solar System; either computational method should, and does, result in the same position (ignoring ellipticity), within the error factors of the mechanism. [26]:7, Information on the specific data gleaned from the ruins by the latest inquiries is detailed in the supplement to Freeth's 2006 Nature article. It is therefore a convenient interval over which to convert between lunar and solar calendars. The functions of the pointers were deduced from the remains of the dials on the back face, and reasonable, appropriate gearage to fulfill the functions was proposed, and is generally accepted.[10][13][71]. ", "On the Trail of an Ancient Mystery – Solving the Riddles of an Early Astronomical Calculator", "Decoding The Antikythera Mechanism – Investigation of An Ancient Astronomical Calculator", "Decoding the Antikythera Mechanism: Supplementary Notes 2", "Mysteries of computer from 65 BC are solved", "The Antikythera Mechanism at the National Archaeological Museum", "History – Antikythera Mechanism Research Project", "Ancient 'computer' starts to yield secrets", "Were there others? [37], The Antikythera mechanism is generally referred to as the first known analogue computer. He mentions a quote from an ancient papyrus: ...a voice comes to you speaking. Each has a pin mounted, potentially on an extension of one side of the gear that enlarges the gear, but doesn't interfere with the teeth; in some cases the needed distance between the gear's centre and the pin is farther than the radius of the gear itself. [65], The Callippic dial is the left secondary upper dial, which follows a 76-year cycle. The following three Egyptian months are inscribed in Greek letters on the surviving pieces of the outer ring:[57], The other months have been reconstructed, although some reconstructions of the mechanism omit the five days of the Egyptian intercalary month. [73], Investigations by Freeth and Jones reveal that their simulated mechanism is not particularly accurate, the Mars pointer being up to 38° off at times (these inaccuracies occur at the nodal points of Mars' retrograde motion, and the error recedes at other locations in the orbit). It is believed that a hand-turned shaft (now lost) was connected by a crown gear to the main gear wheel, which drove the further gear trains, with each revolution of the main gear wheel corresponding to one solar year. [69], Tony Freeth and Alexander Jones have modelled and published details of a version using several gear trains mechanically-similar to the lunar anomaly system allowing for indication of the positions of the planets as well as synthesis of the Sun anomaly. Transactions of the American Philosophical Society, New Series. They are keyed to a parapegma, a precursor of the modern day almanac inscribed on the front face above and beneath the dials. (Weekend Wayfarers / CC … The National Geographic documentary series Naked Science had an episode dedicated to the Antikythera Mechanism entitled "Star Clock BC" that aired on 20 January 2011. Based on the distribution of the times of the eclipses, it has recently been argued that the start-up date of the Saros dial was shortly after the astronomical new moon of 28 April 205 BC. [10][13][71], The Saros train is driven by b1, b2, l1, l2, m1, m3, e3, e4, f1, f2, and g1, which mounts the pointer. Cicero also said 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 ..."[83]. The device is a complex clockwork mechanism composed of at least 30 bronze gears. 10–11. Also written is "223" for the Saros cycle. The object would come to be known as the Antikythera Mechanism. [68], Evans et al. The mechanism was retrieved from a shipwreck found off the coast of the Greek island of Antikythera in 1901. The gear drives a small ball that appears through an opening in the Moon pointer's face, painted longitudinally half white and half black, displaying the phases pictorially. Antikythera mechanism, ancient Greek mechanical device used to calculate and display information about astronomical phenomena. But new work shows the Antikythera mechanism used pure geometry, as … [28], On 17 May 1902, archaeologist Valerios Stais found that one of the pieces of rock had a gear wheel embedded in it. [13] Inscriptions on the instrument closely match the names of the months that are used on calendars from Epirus in northwestern Greece and with the island of Corfu, which in antiquity was known as Corcyra. The Sun gear is operated from the hand-operated crank (connected to gear a1, driving the large four-spoked mean Sun gear, b1) and in turn drives the rest of the gear sets. Since Price’s assessment, modern X-ray and 3D mapping technology have allowed scientists to peer deeper into the remains of the mechanism and learn even more of its secrets. [13][14][15], This artefact was retrieved from the sea in 1901, and identified on 17 May 1902 as containing a gear by archaeologist Valerios Stais,[16] among wreckage retrieved from a shipwreck off the coast of the Greek island Antikythera. [11] Similar to the inferior systems, each has a gear whose centre pivot is on an extension of b1, and which meshes with a grounded gear. The bars could have been full gears, although there is no need for the waste of metal, since the only working part is the slot. The mechanism uses Hipparchus' theory for the motion of the Moon, which suggests the possibility that he may have designed it or at least worked on it. [26]:6 In addition, the inner lines at the cardinal points of the Saros dial indicate the start of a new full moon cycle. 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