Galileo Galilei's Life and Times
Italian Physicist, Mathematician, Philosopher and Astronomer
Jun 13, 2008
Galileo Galilei laid the foundation for the scientific revolution of the 17th century. He turned the telescope into a major instrument. As an inventor, he gave the thermometer, and the pendulum, as a timekeeper leading to clock inventions, and the first simple device for calculating a missile trajectory.
Early Life
Galielo Galilei was born in Pisa on February 15, 1564, son of Vincenzo, who descended from the Florentine family, a talented amateur musician. At the age of 10, he was sent to school at the monastery of Vallombrosa. He spent a few years with tutors in Florence then studied medicine at Pisa University.
Soon, the young Galileo began to challenge his teachers, discovered mathematics and the works of the Greek geometer Euclid, who insisted on clear proofs and demonstrations before anything could be accepted as true, ideas that stuck with Galileo for the rest of his life. He was also influenced by other great Greek mathematicians like Archimedes.
Mathematics, and the Questioning Mind
Galileo was tutored in mathematics by a Florentine court mathematician Ostilio Ricci. He began to teach mathematics at the age of 21. Later he was appointed lecturer at Pisa University. When his father died, he moved to a better-paid post at Padua to support his family, and remained there for 18 years.
While teaching, he began his scientific investigations. His ideas on how things move were in the 1590 essay series called De Motu. He also conducted his famous experiment on the Leaning Tower of Pisa. To show the error of Aristotle's notion that heavier things fall faster, he dropped cannonballs of different sizes and weights from the tower's overhand and showed that they land at the same time. These ideas were developed in his La meccaniche, which combined mathematics and physics to create the new science of mechanics – the science of force and motion.
Galileo's Telescope
In the summer of 1609, he visited Venice and became intrigued by a novelty called a perspicillium made by a Dutch spectacle maker. It consisted of two lenses in a tube and could make a distant steeple look as if it was just across the way. He immediately made one of his own with 10 times as much magnification. He called it a 'telescope' and it became famous throughout Italy.
He used his telescope at night to look at the Moon and the stars. At once he noticed some things. For example, the Moon was not the perfect sphere it was supposed to be. In 1610, Galileo published all his discoveries in The Starry Messenger.
Galileo and the Catholic Church
Galileo's discoveries implied that the Earth was not at the centre of the universe, but moved around the Sun, as Copernicus had suggested 70 years earlier. Galileo's beliefs were seen as heretical to the Bible's creation by the Catholic Church who believed in Ptolemy's model of the universe that the Earth is immobile and the centre of the universe, and not the Sun. He wrote a dialogue he called The Dialogue depicting his case but was forced by the papal authorities to deny it.
Last Years
Despite ailing health, he continued to do scientific research, eventually dying on January 8, 1642, the same year that Newton was born in England.
Galileo's Legacy
Perhaps Galileo's greatest achievement was in understanding how things move, which created the basis for the modern science of physics. For almost 2,000 years, people had accepted the views of Aristotle on how things fall and get faster and slower. Galileo overturned these, and paved the way for Isaac Newton's understanding of force, motion and gravity, half a century later.
Sources:
Farendon, J. and Woolf, A., Rooney, A. and Gogerly, L.. The Great Scientists. Capella, 2005
Gribbin, John. Science a History. London: Penguin, 2002.
Ellyard, David. Who Discovered What When. New Holland, 2005
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