Saturday, August 12, 2017

The Antikythera Device

The wonderfully complex mechanism that predicted eclipses, the positions of the planets, and the dates of Olympic games may have been a collaboration among Archimedes, Eratosthenes, and Apollonius.  Eratosthenes was the Librarian at Alexandria. Apollonius was the best geometer of the time. Or maybe Archimedes built it himself. Although this device is singular, its intricate gearing suggests that it must have been the result of a long series of development. But all the others are lost.
 
from the Freeth Presentation at Stanford
The best citation we have to the mechanical works of Archimedes come from De Re Publica by Marcus Tullius Cicero. You can find the citation archived at “Spheres and Planaria” at NYU Math here:
“Cicero (106-43 BC), De Re Publica, Book I, Sections 21-22
(In this passage Cicero writes of a discussion that takes place in 129 BC among a group of learned Romans. One of them relates an incident in 166 BC in which a Roman consul, Gaius Sulpicius Gallus, is at the home of Marcus Marcellus, the grandson of the Marcellus who conquered Syracuse in 212 BC.)
. . . he [Gallus] ordered the celestial globe to be brought out which the grandfather of Marcellus had carried off from Syracuse, when that very rich and beautiful city was taken, though he took home with him nothing else out of the great store of booty captured. Though I had heard this globe mentioned quite frequently on account of the fame of Archimedes, when I actually saw it I did not particularly admire it; for that other celestial globe, also constructed by Archimedes, which the same Marcellus placed in the temple of Virtue, is more beautiful as well as more widely known among the people. But when Gallus began to give a very learned explanation of the device, I concluded that the famous Sicilian had been endowed with greater genius that one would imagine it possible for a human being to possess. For Gallus told us that the other kind of celestial globe, which was solid and contained no hollow space, was a very early invention, the first one of that kind having been constructed by Thales of Miletus, and later marked by Eudoxus of Cnidus (a disciple of Plato, it was claimed) with the constellations and stars which are fixed in the sky. He also said that many years later Aratus, borrowing this whole arrangement and plan from Eudoxus, had described it in verse, without any knowledge of astronomy, but with considerable poetic talent. But this newer kind of globe, he said, on which were delineated the motions of the sun and moon and of those five stars which are called wanderers [the five visible planets], or, as we might say, rovers, contained more than could be shown on the solid globe, and the invention of Archimedes deserved special admiration because he had thought out a way to represent accurately by a single device for turning the globe those various and divergent movements with their different rates of speed. And when Gallus moved the globe, it was actually true that the moon was always as many revolutions behind the sun on the bronze contrivance as would agree with the number of days it was behind in the sky. Thus the same eclipse of the sun happened on the globe as would actually happen, and the moon came to the point where the shadow of the earth was at the very time when the sun . . . out of the region . . .
(Translation by Clinton W. Keyes in Cicero: De Re Publica, De Legibus, Loeb Classical Library, Harvard University Press, Cambridge, 1928.)”
The Google Doodle for May 17, 2017  celebrated the 115th anniversary of the discovery of the device.  Sponge divers found it amid the treasures of an ancient wreck. Among these are some of the finest bronze statues we have from that context.  Archeologist Valerios Stais (1857-1923) was the first to suggest that the gearing was evidence of a clockwork, but his theory was discounted at the time. The next significant studies were the work of Derek DeSolla Price.
 
PBS NOVA Presentation
Derek John De Solla Price (1922-1983) held two doctorates, one of them in the history of science. You can find 23 one-hour lectures Neolithic to Now from Yale on his honorary blog site. Also there is the full text of Babylonian Science also on his honorary blogsite.  
Derek spent from around 1951 until about 1959 figuring out what that lump was and in a June 1959 Article in Scientific American he first announced to the mass public his theories on the device.” Price DeSolla worked with Charalampos Karakalos who used x-rays and gamma rays to create images of the 82 fragments.  They published 70-page paper, “Gears from the Greeks. The Antikythera Mechanism: A Calendar Computer from ca. 80 B. C.” in the November 1974 issue of Transactions of the American Philosophical Society New Series, 64 (7): 1–70.
 
from Epigraphy.org the lettering styles help to
place the time of construction
In our time, Dr. Anthony Freeth speaks for the team that has decoded much more of the Antikythera device.  Their papers are here:
You can view a 2-hour lecture delivered November 6, 2015, at Stanford.  (I did it in three sittings.) This link takes you to a lead-in article which provides links to their YouTube channel presentation (here) and Apple Store podcast. Freeth answers the basic questions: What, How, When, Where, Who, and Why.
 
Kurt Baty built a faithful LEGO model
That no other similar mechanisms are known is troubling. It is easy to underestimate how much was lost over the centuries of the slow decline of Rome. We know from other citations that the wife of the emperor Claudius was Etruscan. For her, he wrote a history of her people, perhaps in their own language. Not only is that work – the creation of the most powerful citizen of Rome – lost, so is knowledge of the language. We can read the inscriptions we have found, sounding out the letters. Except for the names of some gods such as Minerva and Mercury, and other smatterings, we know nothing. As a weapon of war, a single thermonuclear bomb, exploded 50 miles above the surface will create an electro-magnetic pulse that erases just about all of our electronic storage.  In the wake of even a “limited” nuclear exchange, the subsequent nuclear winter might force us to burn our books to keep warm. Civilization is fragile.

Also on Necessary Facts

No comments:

Post a Comment