Galileo’s Phases of Venus. Many of the diagrams Galileo Galilei (1564-1642) put in his Sidereus Nuncius (Starry Messenger) supported the heliocentric model by demonstrating the movements of ...

Since S is the same regardless of which inner planet we are considering, the geocentric model requires us to accept that the deferents of both Mercury and Venus just happen to be such that they ...

A diagram of the geocentric trajectory of Mars. Kepler’s investigation of the Red Planet’s orbit would lead to his first two planetary laws. (Image credit: Johannes Kepler/PD-US) ...