Precursors of Galileo
Before talking about Galileo, we must quote Copernicus who proposes a solar system with the Sun in the center and the planets revolving around it.
We must quote Kepler who replaces the circles of Copernicus with ellipses and deduces the laws of the displacement of the planets
And we must quote Giordano Bruno who discovers that the demonstration of the immobility of the Earth by Aristotle is false.
Aristotle ignored the laws of inertia and believed that when you stopped pushing an object, it immediately stopped moving. He proved the immobility of the Earth by saying that if we let go of an object, during its fall the Earth continues to move, the object should fall further than the vertical from its starting point. For example, if we threw a stone vertically in the air, it fell at our feet and did not move away from us.
Giordano Bruno noticed that on a boat moving under a good breeze, if something fell from the top of the mast, this thing despite the movement of the boat fell at the foot of the mast. She accompanied the boat during its fall. This called into question Aristotle's demonstration.
Galileo had the opportunity to reflect on this observation, and without ever quoting Giordano that the apostolic and Roman Catholic Church, religion of love preached by Jesus, had burned alive for heresy.