Caleb Frischknecht PHYS. 1010 MWF 8:00 Galileo Galilei Sir Isaac Newton is famously quoted as stating, "if I have seen farther it is bystanding on the shoulders of Giants." the giants to whom he was referring includedGalileo Galilei and Johannes Kepler, especially Galileo. Todays scientists recognizeNewton and Galileo together as the fathers of modern science. It was Galileo whointroduced unwavering, consistent dependence on observation and measurement in theevaluation of scientific theories. Before him, there was no serious observation ormeasurement at all, only metaphysics and dogma. The ancient Greek thinker Aristotlehad made some claims about the natural world. The Catholic Church, a powerful force inEurope at that time, supported and defended those claims that were consistent with itsthen-literal interpretation of the Bible. The most important of those claims was thecosmological scheme called geocentrism. In this scheme earth holds the position as thecenter of the universe, while all the heavenly bodies, consisting of the sun, the moon, theplanets, and the stars, revolve around earth on "spheres." Earth and its inhabitants weredeemed imperfect, while the heavenly spheres and their heavenly bodies were supposedto be perfect. Woe to anybody who questioned that accepted picture of the world. Such aperson was in danger of being ostracized from the community of natural philosophersand, moreover, exposed himself to the wrath of the inquisition, that powerful body of thechurch that "defended" the faith from heresy. Galileo not only questioned the prevailingdogmas about the natural world, but proved some of them wrong. Galileo was born on February 15, 1564, in Pisa in what is now Italy, and was thefirst of the six children of his father, Vincenzio Galilei, and mother, Giulia Ammannati.
Galileos father was a musician and music theorist, who studied such matters as therelation of the pitch of a plucked string to the force stretching the string, the stringstension. This interest exposed Galileo at an early age to the investigation of phenomenathrough measurement. As a young man, Galileo considered becoming a priest, but at hisfathers urging, instead started studying medicine at the university of Pisa. In the middleof his course of study, he switched direction and studied mathematics instead, obtaininghis degree in that field. In 1589, at the age of 25, Galileo was hired to teach mathematics at the universityof Pisa, and three years later he took a position at the university of Padua, where hetaught astronomy and mechanics, in addition to mathematics, for 18 years, until 1610.Although never married, Galileo had three children with Marina Gamba, who were bornduring 1600-06. The two oldest were girls, Virginia and Livia, born in 1600 and 1601,respectively. They were both sent to a convent, where they took the names Maria Celesteand Suor Arcangela and remained for their whole lives. The son, Vincenzio, was born in1606. While at the university of Padua, Galileo made important discoveries in pure andapplied science, including the study of motion, astronomy, and telescope construction. Hetaught for 18 years and during that time, became convinced that there was truth in thetheory of Nicolaus Copernicus, a Polish astronomer, who believed that all planetsincluding earth revolved around the sun. While still at Padua, in 1609, he built the firstastronomical telescope. When he used it to look at the sky, he found that most ofAristotles and Ptolemys theories were wrong. His most important discovery was whenhe discovered the four moons of Jupiter in 1610, which were called the Galilean satellitesin respects to him. Later that year Cosimo de Medici, Grand Duke of Tuscany, named
Galileo his personal mathematician. This brought him back to Florence once again wherehe continued his studies in astronomy. In 1613, he wrote a letter attempting to explain how the Copernican theory wasagreed with both Catholic doctrine and correct Biblical explanation. A few of his enemiesgot a hold of the letter, and sent it to the inquisitors in Rome. The duty of the inquisitorswas to find and discipline people who were against the teachings of the church. Galileowas then brought to Rome to be tried for his “crimes.” Fortunately for him, his chargeswere cleared and he was let go under one condition, which was that he was not to hold ordefend the Copernican theory meaning that he wasn’t allowed to say it was true. Nineteenyears later, in 1632, he published his first book, Dialogue Concerning the Two ChiefWorld Systems. In this composition, he compared Aristotle’s and Ptolemy’s theories tothat of Copernicus. He did this to show that the Copernican theory was more logical thanthe other two. Again the inquisitors tried him and this time he was found guilty. He wassentenced to life in prison, however, due to his old age and poor health, he was allowedhouse arrest in his home just outside of Florence. Eventually Galileo went completelyblind and still managed to write his second book. He died on January 8, 1642, at the ageof 78. His discoveries and theories have helped aid in many more scientificbreakthroughs throughout the years.