Tuesday, January 28, 2014

Copernicus vs. Ptolemy, or, Today's Fact about How Science Evolves

Physicist Frank Tipler:
Many have even claimed that Copernicus was not superior in predictive power over Ptolemy. I myself decided to check this claim, by looking at Tycho's notebooks. I discovered that between 1564 and 1601, Tycho compared Copernicus's predictions and Ptolemy's predictions with his own observations 294 times. As I expected, Copernicus was superior. So Copernicus' theory was confirmed as experimentally superior to Ptolemy long before Galileo. 
I suppose you have to have read a lot of history of science to be as awed by this discovery as I was, but I really must have read in a dozen places that Copernicus' theory was not any better than Ptolemy's at predicting where the planets would be seen. (To be accurate it required the refinements introduced by Kepler, who showed that orbits are elliptical and the speed of planets increases as they near the sun.) But if it really was better, even if not perfect -- and Tycho Brahe was the most accurate naked eye astronomer in history -- that puts its rapid acceptance among astronomers in a completely different light.

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