Galileo Galilei made significant contributions to astronomy, including the improvement of the telescope and the discovery of celestial bodies such as Jupiter's moons. His observations challenged the geocentric model and supported the heliocentric theory, which posited that the Earth orbits the sun. In addition to his astronomical findings, Galileo also laid the groundwork for modern scientific methods through experimentation and mathematical reasoning. His advocacy for empirical observation transformed the scientific community's approach and established fundamental principles that continue to guide scientific inquiry today, marking him as a pivotal figure in the Scientific Revolution.