Galileo Galilee

Renaissance Italy: an era that looked to the ancient classical era for knowledge and inspiration as it moved forward, generating revolutions in art, technology, and science. It was into this world that Galileo Galilee was born. He was born to Vincenzo Galilee, a Florentine musician, on February 15, 1564, in the small and sleepy city of Pisa, Italy. This child would grow up to create revolutions in physics, math, and astronomy; using the experimental method to challenge all known science. This courage to challenge established views may have stemmed in part from his father, Vincenzo, who developed theories on the interconnection of music and mathematics that were not quite in step with the accepted views of the day. Vincenzo taught Galileo music, mathematics, and the importance of asking questions and thinking analytically.  The young Galileo was sent to a monastery in Vallambrosa to receive an education, but was removed by his father due to a supposed inflammation of the eye, shortly before he took his vows as a monk. Had finances allowed it, Galileo would have used his dexterous talents to become an artist. However, the family was impoverished, and Galileo needed a career which could support him. Thus, at 16 he was sent to the University in Pisa to study medicine. However, Galileo was not very interested in medicine, and so he turned to a friend of his fathers, Ostilio Ricci, to study a subject which fascinated his adroit mind: mathematics. After three years Galileo returned to Florence, where his family was now living, to study mathematics openly. The subject of mathematics was not considered a particularly noble one at the time, however the subject was slowly being revived due to the publication of works by Euclid and Archimedes.  

Over the ensuing years, first in Florence and then as a professor of mathematics in the University of Padua, Galileo made tremendous discoveries in the fields of physics and mathematics. Galileo developed the idea of the isochornicity of the pendulum (the principle that every pendulum of the same length will swing in time), the idea of inertia, and studied the effects of falling objects. He used his work on the densities of solids to more accurately solve Archimedes’ gold crown quandary. Hiero, the ruler of Syracuse, had approached Archimedes to determine if the goldsmith who had fashioned his crown had used all the gold given to him, or had substituted some silver. In the famous “Eureka” moment, Archimedes realized that all mass must displace its equal bulk in water; and thus, the by placing the crown in water one could determine its composition, as gold and silver have different densities. Galileo took this theory and expanded upon it by building a hydrostatical balance to measure the densities of matter more accurately. Galileo was an experimental scientist in a world where reliance on the senses was considered inaccurate. Galileo performed experiments to test if his mathematical theories were true in nature. This was in direct contrast to Aristotelian philosophy which said to, “employ reasoning at all times rather than experience”. Most of the philosophers, mathematicians, and scientists of Galileo’s day believed, like Aristotle, that philosophy and theory was infinitely superior to observation, and that the inconsistencies of the practical application of these theories was due to the imperfection of this world and not to anything flawed in the theory.  Galileo’s revolutionary methods of deduction based on observation were looked upon with askance by established academics. Aristotelian’s believed that all heavenly bodies were attached to crystalline orbs which performed perfect circles around the earth. The heavens, they believed were immutable, and only the earth subject to imperfection and change. In this depiction of the universe, heaven and hell were physical places found above and below earth respectively. The Aristotelian model of the universe was proven inaccurate by mathematical calculations, a fact which did not bother those who felt that theory was infinitely superior to mere calculations. However, it convinced those who, like Galileo, felt that the universe only be understood through observation and calculation.

Thus, Galileo turned to the heliocentric model developed by Copernicus in his book On the Revolutions of the Heavenly Spheres, in which he argued that Earth was a planet, and that all planets revolved around the sun. According to Copernicanism, the universe was vastly larger than had been previously thought, something which philosophers refused to accept. Copernicanism was based on calculations and scientific fact unlike the geocentric model which was part and parcel of church doctrine and Aristotelian philosophy.   Because of this, there were no adherers to Copernicus’ model among philosophers, and even among Astronomers there were few. Galileo, however, described heliocentrism as a “most beautiful” theory and praised Copernicus. To the naked eye, it is impossible to choose between these two theories, it would take the invention of the telescope to mark and prove the truth of Copernicus’ theory.

        After three years of teaching at the University of Pisa Galileo was dismissed from his job due to his refusal to wear the professorial robes and skipping lectures. Galileo was not a man who followed the establishment, and in fact wrote a satirical poem, Against the Wearing of the Gown, which poked fun at the robes that universities required professors to wear, clothing in general, and even the church. Galileo was certainly not a very religious man and there are not many documentations of his attending church. However, there is no recorded evidence of his being heretical, something which was extremely dangerous in an age when the church had immense power. This above is important, as it sets the stage for a man who was willing to go against established philosophical and religious views to defend the heliocentric model. Galileo never married, however he did have several children. He was certainly not a very attentive father, but he provided for his children and seemed to have enjoyed some closeness with one of his daughters. It is ironic that although he sent all of his daughters to nunneries, at the end of his life he disowned any descendant who would enter a monastery or nunnery. From 1592 – 1610 he taught at the University of Padua, a much more distinguished university than the one in Pisa, and it was during these years that he made most of his important discoveries in physics, and became a staunch follower of Copernicus.

        Galileo converted to Copernicanism not because of new understanding of astronomy, but rather as a new approach to problems in physics. As a mathematician Galileo appreciated the effect that a moving earth should have on physics. In fact, in a letter that Galileo wrote to Kepler, a leading astronomer of the day, he wrote that Copernicanism helped explain many inexplicable natural phenomena. It helped to explain the experiments he had performed on the falling of objects, as objects from a high tower appear to fall vertically due to principles of the circular inertia of a moving Earth. Galileo also used heliocentrism to develop a revolutionary (though inaccurate) theory on tides, and the principle of the relativity of movement. Galileo argued that all perception of movement is relative and we can therefore not distinguish movement without an external reference point (think of two stationary trains side by side, if one begins to move, it is not distinguishable to a person in one of the trains which one has moved). Thus, while it seems to us that sun is moving around us, it is in fact the opposite.