I always hear people saying "Ptolemy thought that the Sun moved around the Earth, but it is the other way around: the Earth moves around the Sun". I think that's wrong. I think that Copernicus's theory is not "truer" than Ptolemy's. It is just that Copernicus's theory is simpler! But both theories are correct. It is just a matter of defining your reference frame! Am I right? If that's so, why is it that even science teachers, science documentaries, etc. say that Ptolemy was wrong and that Copernicus was right. Thanks!