Galileo's finding that Venus goes through these, like the moon, was the 1st direct evidence for Copernican ideas
The system of Copernicus explained the rising and setting of the sun, moon, .... 
Galileo observed Venus going through a complete set of phases just like the... [DOC] [TLE] GALILEO - What were Galileo's scientific and biblical conflicts with ... [PAR] What were Galileo Galilei's conflicts with the Roman Catholic Church?