What observation, independent of sunspots, provided data that only made sense if Venus orbited the Sun, not the Earth?

Answer

The phases of Venus

The data Galileo collected from observing the phases of Venus could only be logically explained if Venus orbited the Sun rather than the Earth.

What observation, independent of sunspots, provided data that only made sense if Venus orbited the Sun, not the Earth?
Galileo Galileisunastronomyscientistobservation