Final answer:
Galileo Galilei made significant astronomical discoveries with his telescopes, including identifying Jupiter's four largest moons, which supported heliocentric views and challenged conventional beliefs at the time.
Step-by-step explanation:
Galileo Galilei, an esteemed Italian astronomer, used telescopes he refined to make significant astronomical discoveries during the sixteenth and seventeenth centuries. Among these was the detection of Jupiter's four largest moons, which was a groundbreaking find that challenged geocentric views of the universe. While Galileo did not invent the telescope, his enhancements and scientific use of it revolutionized the study of the cosmos, leading to valuable insights such as the nature of craters on the Moon, the presence of sunspots, and the composition of the Milky Way.
His steadfast commitment to observational science and his confrontations with religious authority ultimately resulted in him being tried by the Inquisition and spending his later years under house arrest. However, the validity of Galileo's observations was undeniable and they continued to influence science long after his death, contributing to the eventual acceptance of his ideas by both the church and scientific communities.