When Galileo was still alive, it took place in the 1600’s. Everyone was Christian and believed in GOD. There were enemies of Galileo. They thought they knew everything about the solar system. But they didn’t.
Galileo was famous for his thoughts and ideas. He did not like the prince. He needed to teach prince so he could learn.
He said that all objects fall at the same speed. And they do… on the moon. So therefore, he was half right. He also made the telescope. Convex glass makes things look bigger and concave makes things look smaller. That’s who Galileo is.