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In Defense of Galileo
A failed theory is nothing to be ashamed of
Science is all about testing hypotheses. You can’t decide how to test a theory until you have a theory to test.
Ptolemy’s theory of planetary motion was wrong--thunderously wrong!--but it was a testable hypothesis. It taught astronomers to seek explanations for observations and to match predictions to data.
Copernicus’ theory of planetary motion was not as wrong as Ptolemy. He got the location of the sun right, measured the size of the orbits in Astronomical Units, and calculated the periods of the planetary orbits.
Galileo's theory of the tides was wrong, but it was right for him to guess that they might tell us something about the motion of the earth. After Newton discovered the law of gravity, it was clear that the gravitational pull of the sun and moon as the earth rotates on its axis is the true cause of high and low tides.