Galileo Galilei (1564–1642) was an Italian astronomer, physicist, and mathematician often regarded as the ‘father of modern science’. He pioneered the use of telescopic observations and mathematical analysis to understand nature, laying critical groundwork for the scientific method.
Born in Pisa on February 15, 1564, he studied at the University of Pisa and later lectured at the University of Padua from 1592. There he conducted experiments on motion and mechanics that challenged Aristotelian physics.
In 1609 he built an improved refracting telescope. In March 1610, he published *Sidereus Nuncius*, detailing discoveries that included lunar mountains and craters, the phases of Venus, sunspots, and four moons orbiting Jupiter—the Galilean satellites.
His observations of Venus’s phases, incompatible with the Ptolemaic system, provided strong evidence for heliocentrism.
Galileo formulated early laws of motion—such as the law of falling bodies and the concept of inertia—that anticipated Newtonian mechanics.
Because of his outspoken defense of the Copernican model, he was tried by the Roman Inquisition in 1633, found “vehemently suspect of heresy,” forced to recant, and spent the remainder of his life under house arrest.
His legacy spans observational astronomy, physics, and scientific methodology, inspiring generations to follow empirical and mathematical inquiry into nature.