The influential figure in the development of modern astronomy is Galileo Galilei. His groundbreaking use of the telescope revolutionized our understanding of the cosmos, revealing celestial bodies like Jupiter’s moons and the phases of Venus. Challenging the prevailing Ptolemaic model, Galileo's support for heliocentrism laid the foundation for modern scientific inquiry and the astronomical sciences. His trial by the Church exemplified the conflict between science and religion during the Renaissance.