3.1 The phases of Venus Exploration 3.1.1: It was the observed phases of Venus, as well as the correlation of these phases with the observed size of Venus, that could not be reconciled with the Earth-centered model of Ptolemy. Through the use of diagrams, clarify how the phases of Venus provide falsifying evidence for the Earth-centered model. Explain how the observed size of Venus in correlation with the phases provides further corroboration of the Sun-centered model. .