Who was Galileo Galilei?
Galileo Galilei (1564–1642) was an Italian physicist, mathematician, and astronomer whose telescopic observations confirmed the Copernican heliocentric model. Called the 'father of modern science,' he championed empirical observation over traditional authority. His conflict with the Catholic Church — which condemned him for heresy — became a defining symbol of the tension between science and religious dogma.
Galileo Galilei was the scientist who, more than any other individual, established the methods and attitudes that define modern science. Born in Pisa in 1564, he was a gifted mathematician and experimenter who combined careful observation with mathematical analysis in ways that were genuinely new.
Galileo's early work on motion was revolutionary. Through careful experiments — including rolling balls down inclined planes and studying pendulums — he developed the principles of acceleration and inertia that would later form the foundation of Newton's physics. He disproved Aristotle's claim that heavy objects fall faster than light ones, establishing the principle that all objects fall at the same rate regardless of weight (in the absence of air resistance).
His astronomical observations transformed cosmology. Using an improved telescope of his own design, Galileo discovered mountains and craters on the Moon (disproving the ancient belief in celestial perfection), four moons orbiting Jupiter (demonstrating that not everything orbited Earth), the phases of Venus (consistent with heliocentrism but not geocentrism), and sunspots. These observations provided powerful evidence for the Copernican heliocentric model.
Galileo's trial by the Roman Inquisition in 1633 became the most famous confrontation between science and religious authority. After publishing his Dialogue Concerning the Two Chief World Systems — which clearly argued for heliocentrism despite being framed as a neutral discussion — he was found 'vehemently suspect of heresy,' forced to recant, and placed under house arrest for the remainder of his life. Legend has it that after recanting, he muttered 'Eppur si muove' ('And yet it moves').
Despite his confinement, Galileo continued working, producing his most important scientific work, Two New Sciences (1638), which laid the groundwork for classical mechanics. His insistence that the book of nature 'is written in mathematical language' and that direct observation trumps inherited authority established principles that remain fundamental to scientific practice. The Catholic Church formally acknowledged its error in condemning Galileo only in 1992.