Did anyone catch the History Channel’s show, “Ancient World Mysteries” (IIRC), last night? It was about geared devices built in the ancient world, and the c.1900 discovery of a sunken, geared device that may have been built (or designed) by Archimedes or his protigy? Anyway, the question is this:
The show focused on precision devices known to be made in Greece and Egypt for measuring solar and lunar motion - both diurnal and annual. The crux of the show focused on one sunken treasure, the ruins of a machine which may have simulated planetary positions. But…
For all their great observations of the heavens, surely these folks knew the motion of these heavenly bodies is not constant, unlike the circular gears they used to model with. Didn’t they soon see the error in each machine they built? The History Channel makes it sound too easy. Did the ancient inventors keep searching for other ways to model the heavens? I don’t know when the astrolabe (sp?) came to be, but didn’t that use epicycles to attempt to explain some of the exceptional motion exhibited by the planets?
While my questions would have derailed the flow of this show (which was not a review of astro-models, per se)…maybe the SD knows the whole history? - Jinx
1.) You’re talking about the Antikythera Mechanism. Clever bit of engineering. We’ve discussed it ofen on these Boards:
2.) Yes, the errors in motion did become clear, and increasingly complex models were developed to explain them. But I think you underestimate how complex careful observations are and how complex even simple models can be. There was an interesting article in American Journal of Physics back in the 1980s showing how well you could fit planetary motions to a set of orbits with a single epicycle. I can understand how the idea of circular motion is more appealing than elliptical motion (not to mention infinitely easier to handle theoretically in a pre-algebraic world), and the bias for thinking your vantage point is stationary.
Don’t put down those Greeks and the ones after them. Even when they were wrong, it wasn’t out of stupidity, and things that seem obvious to us with over 2,000 years of hindsight and brilliant thinkers stumbling over bits of the answer certainly weren’t back then. Look at how Claudius Ptolemy carefully measured angles of incidence and refraction and failed to discover Snell’s Law – but did fit the data pretty damned well with a simpler, yet incorrect, formula.