Galileo Galilei
Introduction
It is no question that Galileo was an influential scientist in his time and still is today (picture located on page 6 from google.com). Though his most notable discoveries were in the field of astronomy, we cannot label him simply as an astronomer. He authored many important works including, Sidereal Messenger (also known as Starry Messenger), but unfortunately, due to the power of the Catholic church in his native Italy, his work in astronomy was widely rejected by his countrymen. His contributions to physics also place him in the ranks of the greatest scientists of all time. Without Galileo’s contributions to astronomy, mathematics, and physics, we would lack many basic understandings of the universe and our world.
Body
Galileo Galilei was the son of a musician born in Pisa, Italy in 1564. He studied medicine, but his interests laid in mathematics and physics. At age twenty-five, he became a professor of mathematics at Pisa. In 1591, he moved to Padua and lived there for many years. During his time in Padua, he had a twelve-year long relationship with a Venetian woman named Marina Gamba. The couple never married, but they had three children, two daughters and one son. Later, he moved to Florence where he lived for the remainder of his life. He died in 1642, coincidentally, the year of Sir Isaac Newton’s birth (“Galileo, Galilei (1564 - 1642)”). Galileo’s discoveries contributing to the fields of astronomy are what he is most famous for though this was not his only field of study (picture of his telescope invention on page 6, picture 2 from Rosen). Less notable, though no less important than his astronomical work, are Galileo’s contributions to physics, in particular to the areas of optics and motion, and mathematics. He employed his knowledge of mathematics both as a professor and as means to provide proof to his discoveries such as the height of the mountains on the moon. There is dispute about the extent to which Galileo was influential to philosophy. If we take philosophy to mean the discussion of unanswered questions, then yes, Galileo was as philosopher. But, if we view philosophy as the discussion of metaphysical questions, then he was not (Finocchario, 441). Though he studied medicine, his true passions were mathematics and physics and in 1610, he was appointed to the position of court mathematician and philosopher to the Grand Duke of Tuscany after he discovered of the four moons of Jupiter (located on page 7, first picture from google.com) while working as a mathematics professor in Padua the previous year (Findlen, 1). Before Galileo, there was one earth-shattering discovery in astronomy: Nicolaus Copernicus’s heliocentric model of the solar system. Galileo accepted Copernicus’s theory and believed in the heliocentric solar system. Though we know it to be true today, in the time of Copernicus, and Galileo after him, the idea that Earth was not the center of the solar system was considered radical and caused both Copernicus and Galileo to conflict with the Roman Catholic Church. In fact, the Copernican theory was denounced by the Pope as “dangerous to the faith” in 1616 and Galileo was warned not to uphold it or teach it.
Galileo has been called the father of modern physics and for good reason. Many scientists have traced the roots of their work back to Galileo’s observations including Isaac Newton who gave credit to Galileo for the discovery of many concepts including, but not limited to, inertia and the parabolic trajectory of projectiles (Finocchario, 439).
Galileo also discovered the isochronism, or the constant time of swinging, of a pendulum while he was a medical student by keeping time with his own pulse or, as legend states, by observing a swinging lamp in the Cathedral of Pisa. He observed that the amount of time it took for the pendulum to complete one oscillation was the same no matter the length of the pendulum. He used this knowledge to design a clock that employed a short pendulum as a way to keep time. His son built the clock after his death.
Most importantly, Galileo observed that all objects fall at the same speed regardless of their weight. However, contrary to legend, he did not experiment by dropping weights off the leaning tower of Pisa but rather by rolling spheres down an inclined plane.
Galileo’s most famous discoveries are his contributions to astronomy. Though he did not invent the telescope (it had long been used by sailors and soldiers to view objects in the distance) he improved upon it. The telescope used to view the heavens was supposedly brought to Venice by the Dutch in 1609. Catching wind of this, Galileo built his own telescope and then within a week made another improved version (Rosen, 180). He used it to observe Earth’s moon and other bodies in the solar system. He was the first to observe the phases of Venus, the composite structure of Saturn, Jupiter’s four moons, and mountains on Earth’s moon. Pictured above is Galileo’s personal telescope.
Galileo’s description of the moon was also a point of controversy. As Galileo observed, and as we know today, the moon is a solid object whose surface is rough: covered with mountains and craters. Though this does not shock us, to those living in 17th century Italy, this description was frightening because it did not coincide with a description of the moon in the book of Revelation. The crescent moon, as it appears in the described image, is smooth, possibly translucent, and immaculate. He also developed a mathematical formula for determining the height of the mountains on the moon that employed the geometry of triangles to calculate the height (Swerdlow, 251, 249). Some of Galileo’s hand drawn images of the moon are picture below.
Galileo did not receive any awards or honors for his work during his time. Instead, he was called up by the Holy Office of the Inquisition in 1633 to stand trial for heresy because of his support of the Copernican heliocentric solar system model. He was found guilty and sentenced to house arrest for the rest of his life at the age of 69 and his books were banned. Because of this, Galileo’s supporters in Protestant Holland smuggled his works out of Italy to be published. Scholars also snatched his books up because they were banned, making him more famous.
Galileo was considered a true Renaissance man. As a fun fact, in addition to being an incredible scientist, he was a talented musician and artist. Toward the end of his life, he gradually went blind. Galileo was also friends with Pope Urban VIII who dedicated his book The Assayer to him in 1623. In 1992, Pope John Paul II pardoned Galileo of his guilty conviction for heresy.
Conclusion
Galileo’s contributions to astronomy, physics, and mathematics are considered priceless by today’s standards. Despite his conflict with the church, his ideas spread and influenced the scientists that followed him. Galileo’s discoveries laid the groundwork for the development of principles and applications that we know and use today (statue picture of Galileo located on page 7, picture 2 from google.com).
Honor Pledge
“This work is my own. I have neither given nor received any unauthorized help.” 3/18/13
Kelsey Gibson
Works Cited
Findlen, Paula E. “Galileo, Scientific Entrepreneur.” Science. 7 Jul. 2006: 46-47. JSTOR. Web. 17 Mar. 2013.
Finocchario, Maurice A. “Galileo as Scientist.” Science. 26 Oct. 1979:439-441. JSTOR. Web. 17 Mar. 2013.
“Galileo, Galilei (1564-1642).” Topic Pages. Boston: Credo Reference Contributors, 2013. Credo Reference. 18 Mar. 2013.
Hanson, Norwood R. “ Galileo’s Discoveries in Dynamics.” Science. 29 Jan. 1965:471-477. JSTOR. Web. 17 Mar. 2013.
Rosen, Edward. “Galileo and The Telescope.” The Scientific Monthly. Mar. 1951:180-182. JSTOR. Web. 17 Mar. 2013.
Sis, Peter. Starry messenger: a book depicting the life of a famous scientist, mathematician, astronomer, philosopher, physicist, Galileo Galilei. New York: Farrar Straus Giroux, 1996. Print.
Swerdlow, Noel M. The Cambridge Companion to Galileo. Cambridge University Press. Print.

Wade, Nicholas J. “Galileo’s Vision.” Cortex. 2009:793-794. Science Direct. Web. 17 Mar. 2013.

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