Galileo Galilei (1564–1642) was an Italian astronomer, physicist, mathematician, and engineer, widely regarded as the "father of modern science," "father of modern astronomy," and "father of modern physics." Born in Pisa, Italy, he initially studied medicine but switched to mathematics and natural philosophy, eventually pioneering the experimental scientific method
. Galileo made fundamental contributions to the sciences of motion, astronomy, and strength of materials. He formulated the law of falling bodies, the principle of inertia, and described projectile motion. He was one of the first to use mathematical analysis and experimentation to understand nature
. He built an improved refracting telescope with which he made groundbreaking astronomical observations: discovering the four largest moons of Jupiter (now called the Galilean satellites), observing the phases of Venus, the mountains on the Moon, sunspots, and Saturn's rings. These observations strongly supported the Copernican heliocentric model, which posited that the Sun, not Earth, was at the center of the solar system
. His advocacy of heliocentrism brought him into conflict with the Roman Catholic Church. In 1633, he was tried by the Inquisition, found guilty of heresy for supporting Copernican theory, forced to recant, and sentenced to house arrest for the rest of his life
. Galileo also invented or improved scientific instruments such as the thermoscope, military compasses, and an early microscope. His work laid the foundation for modern physics and observational astronomy, and he is celebrated as a key figure in the scientific revolution
. He died under house arrest on January 8, 1642, near Florence, Italy
