© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo Galilei was born February 15, 1564, in Italy near Pisa. The Leaning Tower had been completed for about 200 years. Shakespeare was born the same year in England.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo Galilei did not set out to become a great scientist. He made most of his discoveries through ordinary means--by observing and questioning everyday phenomena.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 When Galileo was 17, he entered the University of Pisa to study medicine.

During his first year, he noticed a lamp swinging in the cathedral and observed that the lamp always took the same amount of time to complete an oscillation, no matter how large the swing.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Thus, by the age of 19, Galileo’s first accomplishment was to discover and define isochronism: the period of a swing of a pendulum is independent of its amplitude (arc). - same chronismiso - time isochronism chronism iso

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 During his tenure as a math professor at the University of Pisa, Galileo supposedly threw objects off the Leaning Tower of Pisa to see if their mass made any difference in the mass made any difference in the amount of time it took the objects to fall. amount of time it took the objects to fall. Three years later, his contract was not renewed, probably because he disputed Aristotlelian professors.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo also disproved Aristotle’s famous theory stating that large and small objects dropped at the same time will fall to the earth at different times. He first thought about this during a hailstorm, when he noticed that all sizes of hailstones hit the ground at the same time.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 When Galileo was 33, he constructed a military compass. He received lots of attention and money as a result of this invention.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Soon after, he made a series of telescopes of much higher quality with more than 20X the magnification of the Dutch instruments. When Galileo was 35, he heard about a spyglass (telescope) developed by a Dutchman.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Objective lens gathers and bends light for focusing. light path Eyepiece Galileo constructed a refracting telescope.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo’s work with telescopes and his astronomical discoveries led him to dispute another one of Aristotle’s tenets, that the heavens were perfect and immutable.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 With his more powerful telescopes, Galileo began making astronomical discoveries, including, mountains and valleys on the moon image courtesy of NASA

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 four satellites of Jupiter Jupiter's four largest (of 13 known moons) are known as the Galilean satellites. From top to bottom, the moons shown are Io, Europa, Ganymede and Callisto. image courtesy of NASA

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 sunspots image courtesy of NASA

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 and the phases of Venus. image courtesy of NASA

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo made careful observations and published his findings in a book, Sidereus Nuncius (Starry Messenger). He claimed that all of his observations made sense only if the Earth and all the planets revolved around the sun, a theory called heliocentrism. Heliocentrism was first introduced by Copernicus, an astronomer from Poland.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Heliocentrism went against the teachings of Aristotle, the ancient Greek philosopher whose geocentric theories were supported by the Catholic Church. Galileo boldly continued to be a big supporter of the Copernican theory.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 As a result of his findings, Galileo made a lot of enemies and was called before the Inquisition. The Inquisition was a permanent organization of the Catholic Church created in the Middle Ages, headed by the Pope, and established specifically to deal with heretics, those who publicly disagreed with the teachings of the Roman Catholic Church.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo did not see a conflict between science and religion. He believed that science reinforced the idea of God. The Catholic Church interrogated Galileo and strongly warned him to present his findings as hypotheses, not facts. Galileo published another work after discovering 3 new comets, again supporting his theory of heliocentrism.

© 2006 Plano ISD, Plano, TX/Klein ISD But to want to affirm that the sun really is fixed in the center of the heavens and only revolves around itself (i. e., turns upon its axis ) without traveling from east to west, and that the earth is situated in the third sphere and revolves with great speed around the sun, is a very dangerous thing, not only by irritating all the philosophers and scholastic theologians, but also by injuring our holy faith and rendering the Holy Scriptures false. Cardinal Robert Bellarmine, speaking for the Pope, had this to say about Galileo’s findings:

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo published a third book in total support of heliocentrism and portraying others as fools who supported other views. The Catholic Church found Galileo strongly suspicious of heresy and sentenced him to house arrest at his villa in Arceti for the rest of his life. He was forbidden to publish and forced to recant. Click for trial details!

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo’s health declined, he lost his eyesight, and the death of his daughter left him without support. Galileo was 78 years old when he died in 1642.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Galileo died in Arceti. His remains were later moved to Florence where he was buried close to Michelangelo. Pisa. Florence. Florence. Arceti. Arceti

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Philosophy professors and theologians were both responsible for Galileo’s accusations of heresy. In 1979, Pope John Paul II ordered an investigation into Galileo’s situations, and in 1992, the Vatican acknowledged its errors.

© 2006 Plano ISD, Plano, TX/Klein ISD 2007 Bibliography Van Helden, Albert. (1995). Galileo Timeline. [Online]. Available: Blotzer, Joseph. (1910). Inquisition. The Catholic Encyclopedia, Volume VIII. [Online]. Available: Field, J.V. (1995). Galileo Galilei. [Online]. Available: “Galileo”. (13 Dec 2001). Microsoft Encarta Online Encyclopedia. [Online]. Available: 0&pt=1