Galileo built his own telescope made
observations that made people believe in Copernicus's sun-centered solar system
model called the heliocentric model. The observations include:
1. Jupiter has moons orbiting it.
In addition, Galileo saw the
planet's moons were moving with it.
Sun moves from east to west.
Galileo observed that the Sun has spots. The changing number(/appearance)
of sunspots visible from Earth concludes that the Sun rotates on its own axis.
3. Planets appear to move backward.
He observed that planets were moving in
retrograde direction, appearing to move westward.
Venus has phases similar to the
established that Venus is circling the Sun, not Earth.