Tendex rating and Copernicus
deano said: "My favorite example is that people used to think that orbital physics was all built on circles."
A good book to read about the paradigm shifts in astronomy is Thomas Kuhn's "The Copernican Revolution." Everybody knew that the earth was the center of the universe and everything rotated around it in big circles. That's the Ptolomeic view. But the ancients saw that the 7 visible planets "wandered" about the sky and they created an elaborate model of crystal spheres rotating within crystal spheres in order to predict the retrograde movement of the planets in the sky. Copernicus was tired of trying to explain every newly discovered inaccuracy in the system by inventing another crystal sphere. He changed the paradigm. He imagined a heliocentric universe. Probably the most stunning abrupt change in Western thought. People gradually over about 100 years changed to this view, despite being branded as heretics and forced to recant their findings (like Gallileo) and despite the fact that Ptolomy's system was a BETTER PREDICTOR of where the planets would be. It was only after later gestalt shifts by Kepler (realizing that the planets moved elliptically) and Tycho Brahe that the predictive power of Copernicus's view caught up with it's imaginative power.