Boomer12k wrote:I wonder if it used EPICYCLES to predict planetary positions. Because elliptical orbits, and a Sun Centered Solar System were not in vogue at the time, nor for a very long time after. But if it was to be accurate, it would not use them...and if it DID NOT use epicycles....then who had it right?????
Yes, the Mechanism may have used epicycles.
http://www.guardian.co.uk/science/blog/ ... -astronomy
This is an animation of Michael Wright's reconstruction of the Mechanism. You can clearly see the epicyclic movement of the planet hands and less clearly the various gear assemblies labelled as "epicyclic". But the Mechanism is incomplete, and this is his interpretation.
See the Wiki entry for an accessible and short discussion of the different interpretations:
It should be realised that the Mechanism was built to simulate the planetery movement for a period of about nineteen years. It was not a universal predictor, although that it was built at all was extraordinary.
It was built to simulate the movements that the Greek observers saw. In that it was accurate.
All of science is building complex models of reality, but rarely as a real world model as in this exquisite example. Many of our models do not reflect the true nature of the Universe because of our limited knowledge. At that time a 'cutting edge' of technology was gear wheels and the word 'epicyclic' is a jargon word for a gear wheel concept. The Mechanism employed that technology to describe and visualise the observed movement of the Planets. In the 21st Century, in exactly the same way, we have used the new concept of 'dark' energy and matter to describe the observed movement of galaxies.
In two thousand years, if we are still here, I hope that Boomers then will not accuse our models of being right or wrong, but they will recognise that we did our best with the ideas and technology we have now.