The correct answer is - established that the universe was sun-centered, or heliocentric.
Copernicus and Galileo were two of the scientists that managed to make a huge difference with their theories and discoveries, and help a lot in the change of the societies and eventual loss of the rule of the church. While Copernicus only had theories that the universe is sun-centered, but no proofs, he was ridiculed, and his theories were not accepted at the time. Galileo though managed to create a telescope. With his invention, he managed to prove the theories of Copernicus, and since he had a proof, it was much easier for the theory to be accepted. It needed time though, as the church was trying to block his research and publications about any such thing, but eventually it got to the public, and with his invention being able to provide the people with the proof, the theory was accepted. While this theory is not totally right, it still managed to make a huge difference, and further researches started to take place gradually, constantly pushing the boundaries and putting the science in front of the theology.
