Hidden History: Lost Civilizations, Secret Knowledge, and Ancient Mysteries by Brian Haughton (beginner reading books for adults txt) 📕

strange object was too intricate to belong to a wreck dated by the pottery on board to the early first century B.C. Many researchers thought that the mechanism was the remains of a medieval astrolabe, an astronomical device for observing planetary movements, and used for navigation. (The earliest known example of which is from the ninth century A.D. in Iraq.) But no general agreement on the date or purpose of the artifact was reached, and the enigma was soon forgotten.

In 1951, Derek De Solla Price, an English physicist, and at the time professor of the history of science at Yale University, became fascinated by the complexity of the shipwreck mechanism, and began what was to be eight years of detailed study using x-ray photography. In June 1959, the conclusions of his analyses were published as an article in Scientific American entitled "An Ancient Greek Computer." X rays of the mechanism

revealed at least 20 separate gears, including a differential gear, previously thought to have been invented in the 16th century. The differential gear allowed the rotation of two shafts at different speeds, as used on the rear axle of automobiles. Price deduced from his research that the Antikythera find represented the remains of a "great astronomical clock," which had close ties to "a modern analogue computer." These conclusions met with some unfavorable reactions from scholars. A certain professor refused to believe in the possibility of such a device, and hypothesized that the object must have been dropped into the sea in medieval times and somehow made its way into the wreck.

In 1974, Price published the results of more complete research based on further X rays and gamma radiographs by Greek radiographer Christos Karakalos, as a monograph entitled Gears from the Greeks. The Antikythera mechanism, a calendar computer from ca. 80 B.C. Price's further study showed that the ancient scientific instrument actually contained at least 30 gears, although most of them were incomplete. However, enough of the gearing remained for Price to work out that when its handle was rotated, the mechanism was meant to show the motion of the moon, sun, probably the planets, and the rising of the major stars. The device was in effect a complicated astronomical computer, a working model of the solar system, which had once been contained inside a wooden box with hinged doors to protect the mechanism inside. From the inscriptions and the position of the gears (and year-ring on the object), Price concluded that it had a close connection with Geminus of Rhodes, a Greek astronomer and mathematician who lived from approximately 110 to 40 B.C. Price believed the Antikythera Mechanism to have been built and designed on Rhodes, a Greek island off the coast of Turkey, probably by Geminus himself around 87 B.C. Indeed, the shipwreck had contained storage jars from the island of Rhodes in its cargo, and was thought to have been journeying from Rhodes to Rome when it sank. The date of the vessel's sinking has been fairly securely tied to somewhere around 80 B.C., so presuming that the object was already a few years old when it was lost, a date for the construction of the Antikythera Mechanism of around 87 B.C. is now generally accepted.

It is conceivable then-in terms of date-that the device could have been made by Geminus on the island of Rhodes, especially as Rhodes is known to have been a center of astronomical and technological research in this era. The second century B.C. Greek writer on mechanics, Philo of Byzantium, describes the polybolos, which he witnessed on Rhodes. This amazing catapult had the capacity to fire repeatedly without the need to reload, and possessed two gears linked by a chain drive powered by a windlass (a lifting device consisting of a horizontal cylinder rotated by a crank). Rhodes was also the place where the Greek Stoic philospher, astronomer, and geographer Poseidonius (c. 135 B.c.-51 B.C.) established the nature of the tides. In addition, Poseidonius made a fairly accurate (for the time) measurement of the size of the sun, and also calculated the size and distance of the moon. The astronomer Hipparchus of Rhodes

(c. 190 B.c.-120 B.C.) is credited with the invention of trigonometry and was the first to scientifically catalogue the positions of the stars. Furthermore, he was one of the first Europeans to use observations and information from Babylonian astronomy for his own research into the solar system. Perhaps elements of Hipparchus's knowledge and ideas were used in the construction of the Antikythera Mechanism?

The Antikythera Device is the earliest surviving item of complex mechanical technology. The use of gear wheels more than 2,000 years ago is nothing less than astonishing, and its fine workmanship is as highly developed as any 18th-century clock. In recent years, a number of working reconstructions of this ancient computer have been assembled, one being a partial reconstruction by Australian computer scientist Allan George Bromley (1947-2002) of the University of Sydney, together with clockmaker Frank Percival. Bromley also made more accurate x-ray images of the object, which were the basis of a 3D model of the mechanism produced by his student Bernard Gardner. A few years later, English orrery maker (an orrery is a mechanical model of the solar system) John Gleave constructed a full working model, with the front dial depicting the yearly progress of the sun and moon through the Zodiac against a representation of the Egyptian calendar.

The most recent study and reconstruction of the object was made in 2002 by Michael Wright, the curator of mechanical engineering at the Science Museum in London, working together with Allan Bromley. Although some of the conclusions of Wright's new study disagree with certain aspects of Derek De Solla Price's work, Wright does imply that the mechanism is even more ingenious than Price thought. To arrive at his theories, Wright used X rays of the object using a method known as linear tomography. This technique can show detail from a single plane or region of an object in sharp focus. Wright