3.2.2 How did Galileo seal the case for Earth as a planet? – Earth & Space Science
Galileo Galilei Discovers the Moons of Jupiter and the Phases of Venus - Owlcation
In Jan 1610, Italian astronomer Galileo saw four objects orbiting Jupiter, discovering that 4 moons revolve around the planet (Io, Europa, Calisto & Ganymede). His telescope revealed more stars than are visible
What did Galileo discover? | BBC Sky at Night Magazine