Deciphering and Appeasing the Heavens: The History and Fate of an Ancient Greek Computer

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Deciphering and Appeasing the Heavens: The History and Fate of an Ancient Greek Computer
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  T he Greeks incorporated cunning craftsman-ship, inventiveness and beauty in everything they made. Techne  , the term they used to describe this, was the mother of their culture. Aristotle, who shaped the nature of Greek science and invented zoology, admired craftsmen for their useful devices and wisdom [1]. In fact, of all classes in a polis, he considered craftsmen the most essential. No polis could exist without mechanics practicing their arts and crafts. Of those arts and crafts, Aristotle said, some are “absolutely necessary,” while others enrich life [2]. This Greek mechanics gave birth to the  Antikythera Mechanism, discussed below. T HE  T REASURE   FROM   THE  S EA  On around Easter Sunday 1900, Greek sponge divers discov-ered the remnants of an ancient ship in the waters of the Ae-gean island of Antikythera. The most precious artifact within this treasure trove was a small piece of metal with gears. Ar-chaeologists of the National Museum in Athens categorized it as an astrolabe [3].The shipwreck probably happened in the mid-1st century BCE . The doomed Roman ship, sailing from Rhodes to Rome, carried looted Greek treasure: more than 100 bronze and marble statues, amphorae and coins. Some of the amphorae came from Rhodes. The silver coins srcinated in Pergamon, a Greek kingdom in northwestern Asia Minor, and the bronze coins were from Ephesos, a Greek polis about 100 miles south of Pergamon. The bronze coins, which dated from 70 to 60 BCE , helped to date the doomed Antikythera ship. One memo-rable statue, the Antikythera Youth, is a bronze masterpiece of a male nude from the 4th century BCE .The mechanism, calcified and covered with seashells, was kept in a crate until May 1902, when an archaeologist, Spyri-don Stais, unpacked it and saw a Greek inscription on its sur-face. Others noticed perfectly cut triangular gear teeth.In 1905, Konstantinos Rados, a naval historian, declared that the Antikythera device was too complex to be an astro-labe [4]. In 1907, the German philologist Albert Rehm sided  with Rados [5]. Rehm correctly suggested that the Antikythera clockwork resembled the Sphere of Archimedes, which Cicero de-scribed in the 1st century BCE .  Archimedes was a mathemati-cian and engineer of the 3rd cen-tury BCE  (Article Frontispiece).Cicero recounted that the plan-etarium of Archimedes repro-duced the movements of the sun and moon and the planets Venus, Mercury, Mars, Saturn and Jupiter. The same eclipse of the sun that happened on the globe of  Archimedes would actually happen in the sky [6].Rehm worked on the device for several years; he died prema-turely, however, and his work remained unpublished.In the 1920s, a Greek admiral, J. Theophanides, opined that the ancient mechanism was a navigational device that could tell the position of certain planets [7]. G EARS   FROM   THE  G REEKS The next important phase in the decipherment of the Antiky-thera Mechanism began with Derek de Solla Price, a British physicist and historian of science then teaching at Yale Univer-sity. In studying the papers of the Greek scientists and those of Rehm, Price came to the understanding that the Antikythera Mechanism was probably the most sophisticated technological artifact of the ancient Greeks and that it remained unrivaled for 1,500 years.In 1971, Price asked the Greek nuclear physicist Charalam-bos Karakalos to X-ray the Antikythera fragments. In summer 1972, Karakalos took hundreds of radiographs of all large frag-ments. Price wanted to know how the gearwheels meshed with each other and how many teeth each wheel had. Only then could he figure out the purpose of the Greek machine. He eventually left us “Gears from the Greeks,” a masterful scientific record of his assessment of the Antikythera Mechanism [8].Price took 16 years to master the intricacies of the device. He reported that the Antikythera Mechanism, dating from about 150 to 100 BCE , was “one of the most important pieces of evidence for the understanding of ancient Greek science and technology” [9]. He explained why: The complex gearing of the Antikythera Mechanism shows a more precise picture of the level of Greek “mechanical proficiency” than that indi-cated by the surviving textual evidence. This “singular artifact,” he said of the Antikythera Mechanism, © 2012 ISAST   LEONARDO, Vol. 45, No. 3, pp. 250–257, 2012  251 HISTORICAL PERSPECTIVE Deciphering and Appeasing the Heavens: The History and Fate of an Ancient Greek Computer  Evaggelos Vallianatos  Evaggelos Vallianatos (historian, writer, environmentalist), 675 W. 10th Street, Claremont, CA 91711, U.S.A. E-mail: <evaggelosg@gmail.com>.See <www.mitpressjournals.org/toc/leon/45/3> for supplemental files associated with this issue.  ABSTRACT I n 1900, Greek sponge divers discovered an ancient Greek treasure in the waters of the Aegean island of Antikythera: a device with gears dubbed the Antikythera Mechanism. Scientists studied it for almost a century and eventually declared it the most advanced machine preserved from the ancient world. This device predicted solar and lunar eclipses and harmonized the Greeks’ sac-rifices to their gods with their Panhellenic games and agricul-ture. This geared computer from the 2nd century BCE is now said to mirror the philosophy of Aristotle and the science of Archimedes. It was the product of an advanced Greek techno-logical infrastructure that early Christians destroyed.  Article Frontispiece. Works of Archimedes  , Basel, 1544. (Reproduced by permission of The Huntington Library, San Marino, California.)  252 Vallianatos,  An Ancient Greek Computer the oldest existing relic of scientific technology, and the only complicated mechanical device we have from antiq-uity, quite changes our ideas about the Greeks and makes visible a more contin-uous historical evolution of one of the most important main lines that lead to our civilization [10]. Price described the differential gear of the Antikythera Mechanism as the cornerstone of the computer’s technol-ogy. The differential gear enabled the  Antikythera Mechanism to show the movements of the sun and the moon in “perfect consistency” with the phases of the moon. “It must surely rank,” Price said of the differential gear, “as one of the greatest basic mechanical inventions of all time” [11] (Fig. 1).In fact, in keeping with the near disap-pearance of the Antikythera Mechanism’s technology in late antiquity, the differ-ential gear disappeared for more than a millennium and a half. Price shows that its reinvention eluded Leonardo da Vinci and that it reappeared in 1575 in a clock made by Eberhart Baldewin in Kassel, Germany. This gear and the clockwork culture that developed it advanced the technology of cotton manufacture in the 18th century. Eventually, the differential gear ended up in automobile designs in the late 19th century.Price complained that the West now  judges the Greeks from scraps of build-ing stones, statues, coins, ceramics and a few selected written sources. Yet, when it comes to the heart of their lives and culture, we have practically nothing from the Greek past. We do not have artifacts that show how they carried out agricul-ture, how they built the perfect Parthe-non, what kind of mechanical devices they employed in war, how they used metals or, in general, what the Greeks did in several fields of technology. As Price wrote:  Wheels from carriages and carts survive from deep antiquity, but there is abso-lutely nothing but the Antikythera frag-ments that looks anything like a fine gear  wheel or small piece of mechanism. In-deed the evidence for scientific instru-ments and fine mechanical objects is so scant that it is often thought that the Greeks had none [12]. Price was correct, particularly on the  value he put on the fragments of the  Antikythera device. In this insight, he surpassed his critics and others who maintained that the Greeks had no technology to speak of. (In 1968, the best-selling Swiss writer Erich von Dan-iken in his book Chariots of the Gods   advanced the fiction that important technologies in the ancient world were products of extraterrestrial astronauts or gods.)This nonsense that the Greeks lacked technology fooled millions for a long time. Finally, in 2005,   more than 20 years after Price’s death in 1983, a group of international scientists was formed to settle the controversy over the ancient device’s scientific significance and func-tions. Key members included a British mathematician and filmmaker, Tony Freeth; a British professor of astronomy, Mike Edmunds (University of Wales); and two Greek professors of astronomy,  J. Seiradakis (University of Thessalonike) and Xenophon Moussas (University of  Athens). Freeth, who brought to bear creativity and innovation, convinced two companies, X-Tek of England and Hewlett-Packard of the U.S.A., to volun-teer their imaging technologies for study of the Antikythera Mechanism.In September and October 2005, tech-nicians used a 10-ton machine to take 3D photos and nonlinear computer tomog-raphies of the Antikythera Mechanism. They also exposed the 82 fragments of the 32 known gears of the computer to X-ray bombardment unprecedented in intensity and sophistication. From thousands of X-ray tomographs of the interior and exterior of the ancient ma-chine, there emerged evidence of the machine’s architecture and engineer-ing, and even of a users’ manual (Fig. 2). Now it was possible to understand more clearly how the Antikythera computer  was constructed.The fragments bore inscriptions in ancient Greek. Moussas hired physicist  Yanis Bitsakis to assist Agamemnon Tse-likas, director of the Center for History and Paleography, with the reading of those inscriptions from the computer tomographies. The Greek letters were  very small; some were smaller than 2 mm. The first inscription Bitsakis and Tselikas translated was on the back of the Anti-kythera Mechanism. It read: “The spiral [ !"#$# ] divided into 235 sections.” This meant that one of the back dials was a spiral representing the 19-year Metonic moon and sun calendar of 235 months. Other back dials predicted the eclipses of the sun and the moon. Inscriptions on the front dials, on the other hand, con-cerned the days of the year; the zodiac ran clockwise around them. These in-scriptions allowed one to determine the date based on the rising and setting of constellations. Moreover, the front dials showed the movement and position of the sun, moon and the planets in the zo-diac. They also revealed the phases of the Fig. 1. The Antikythera Mechanism: The largest gear, the Wheel of the Sun. (Photo © Xeno- phon Moussas)  Vallianatos,  An Ancient Greek Computer  253 moon. Indeed, the entire device became a text (Fig. 3). The scientists reported the  Antikythera device is “an extremely rare srcinal document that gives us critical information about the astronomy and technology of its era” [13].The celestial Antikythera device was alternatively like a laptop computer the size of a shoebox, which, according to the scientists, exhibited “longitudes of heav-enly bodies on the front dial, eclipse pre-dictions on the lower back display, and a calendrical cycle believed to be strictly in the use of astronomers on the upper back display” [14] (Fig. 4). T HE  G REEKS ’ A  DVANCED  T ECHNOLOGY  The scientists also concluded that the  Antikythera Mechanism was in its time the most sophisticated technology in the Mediterranean and remained so for more than a millennium. They published their reports in the 30 November 2006 and 31 July 2008 issues of Nature  . Like Price’s 1974 report, these two Nature ar-ticles are fundamental in the decipher-ment of the Antikythera Mechanism. They complement each other, with the 2006 and 2008 reports building on the technical detail of Price, who had also de-scribed the Antikythera Mechanism as a “singular artifact” and an “astronomical or calendrical calculator” that turned out to be “the most enigmatic, most com-plicated piece of scientific machinery known from antiquity” [15].Freeth et al. admired the ancient de- vice’s “great economy and ingenuity of design.” The Antikythera Mechanism, they concluded, “stands as a witness to the extraordinary technological poten-tial of ancient Greece, apparently lost  within the Roman Empire” [16]. C HRISTIANITY   O BLITERATED  G REEK   T ECHNOLOGY  The truth is simpler. The Christians de-stroyed the technological achievements and potential of the Greeks. The technol-ogy of the Antikythera Mechanism was not merely lost; the Christians made it obsolete, that is, made it disappear. The Romans were brutal, but it was the Chris-tians, not the Romans of the pagan era,  who removed the Greeks’ contributions from the landscape.The apostles directed Christians, “Stay clear of all Greek books” [17]. The church fathers denounced the Greeks, accepting the utility of Greek logic only where Greek philosophy was made a handmaiden of Christian theology. In 391–392, Chris-tians burned the nearly intact Library of  Alexandria [18], which possessed most of the books of the Greeks; the Christians brought the Olympics to an end in 393; they imported barbarians to smash the Greek temples in 396.In 415, Christian monks killed the Greek philosopher and mathematician Hypatia. Around that time, Augustine, the most important church father of the Latin West, preached that all that a Christian needed was the Bible. In 484, Emperor Zeno defiled the Parthenon, plundering its chryselephantine statue of  Athena by Pheidias, one of the foremost Greek sculptors of the 5th century BCE . In 529, Emperor Justinian shut down the Platonic Academy, which had been the greatest university of Greece for about 900 years. These barbaric acts were part and parcel of an extremely effective and sustained Christian attack against Greek culture [19].The investigators of the Antikythera Mechanism all ignored the effect of Christian actions, which must have al-most obliterated Antikythera-like de- vices and other technology throughout the Greek world. Christian acts against pagan ideas explain the rarity of the An-tikythera computer. By means of terror and propaganda, followers of Christian-ity devalued Greek culture so much that the arts of civilization, including technol-ogy and science, fell into a precipitous decline. Also, as a matter of course, the Christians melted down or burned the bronze devices and statues of antiquity.For example, in the mid-4th century, Firmicus Maternus, a Christian apologist, appealed to the brother emperors Con-stantius and Constans to “take away . . . the adornments of the temples. Let the fire of the mint or the blaze of the smelt-ers melt them down” [20]. Palladas, a Greek poet of the 5th century, witnessed a smith transforming a statue of Eros into “a frying-pan” [21]. In the early 5th century, the Christian historian Sokrates documented the Christians’ recasting of the Greek bronze statues of the Library (Serapeion) of Alexandria into “pots and other convenient utensils for the use of the Alexandrian church” [22].The fires of the mint and the blazes of the smelters must have consumed Anti-kythera Mechanism–like devices. In the new Christian society, such devices would have lost all utility and meaning.Despite such violence, not all Chris-tians hated the Greeks. The Nestorians, for example, became instrumental in the preservation of some Greek texts. They  were branded heretics and fled to Persia, carrying with them Greek books. In the 8th century, the caliphs of Islam turned to the Nestorians for the translation of the Greeks’ scientific and philosophical  works into Arabic. In addition, Greek Christians in medieval Greece copied and protected the key ancient Greek texts that have lasted to our time. Fig. 2. Part of the users’ manual. At center it reads, “So we know four,” and below this, “76  years,” “19 years,” representing the Callippic and Metonic lunisolar periods; “223” [months]; “divided”; and then “ecliptic months.” (Photo © Xenophon Moussas)  254 Vallianatos,  An Ancient Greek Computer H UMAN    AND  D IVINE  O RDER  The Antikythera Mechanism also pro- vided the names and schedule of the Panhellenic games: OLYMPIA   for the Olympics; NEMEA   for the Nemean games; ISTHMIA   for the Isthmian games at Korinthos; PYTHIA   for the Pythian games at Delphi; and NAA   for games in Dodona in Epiros. Since the Greeks did not need a computer to tell them the times of their Panhellenic games, which for more than a millennium were the most important political, social and re-ligious celebrations in their civilization, the Olympiad dial on the Antikythera device served another purpose.Freeth et al., in their 2008 report,  were right in saying, “It is perhaps not extravagant to see the Mechanism as a microcosm illustrating the temporal har-monization of human and divine order” [23] (Fig. 5). That is exactly the nature of the Antikythera Mechanism. Price would have agreed with this conclusion.Thus, the considerable scientific and political value of such a small machine  would argue for its widespread use and ownership. This suggests dozens of such computers all over the Greek world and more than one place manufacturing them. In contrast to the 14th-century Dondi astronomical clock, set upon a church tower, the Greek computer was not a plaything for the rich. It did not simply vanish.In 1983, a Lebanese man sold to the Science Museum of London a sundial possibly constructed in Constantino-ple, in all probability around the early 6th century. This device had 4-toothed  wheels and a ratchet carried on 2 small axles. One of the wheels had 59 teeth; this wheel measured the movement of the moon. Like ancient lunar calen-dars, this sundial represented a 30-day month followed by a 29-day month, the gearwheel turning a tooth a day. This sundial is the oldest surviving Greek clockwork device after the Antikythera device. To find anything resembling this technology, one has to look ahead to the 11th century, when al-Biruni, a Persian scientist, described a geared calendar mechanism.Price was right that the Greek knowl-edge of gears was passed on to the Arabs,  who made their own clockwork calendars. In addition, the construction of the Con- stantinople sundial showed that the in-strument, clearly descended from the  Antikythera model, was not a luxury toy but an everyday calendar. Fig. 3. From the letters of the manual, the archaeologist C. Kritzas estimated the mecha-nism’s date of construction to be between 150 and 100 BCE . (Photo © Xenophon Moussas)Fig. 4. The  Wheel of the Sun seen from behind. (Photo © Xenophon Moussas)
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