Summarize galileos discoveries in astronomy

 Perhaps Galileo's most important contribution was to be the first to document, with physical evidence, that the Earth might actually not be the center of the Universe. He did this when he discovered the four largest moons of Jupiter which orbited that planet and not Earth. 
He also discovered sunspots, showing that not everything in the heavens was perfect, as the Church maintained. 
Helio "I knew it all along." Centrist