1. Galileo (1564-1642) An Italian scientist, Galileo was renowned for his contributions to physics, astronomy, and scientific philosophy. He is regarded as the chief founder of modern science. An Italian scientist, Galileo was renowned for his contributions to physics, astronomy, and scientific philosophy. He is regarded as the chief founder of modern science. Galileo was condemned by the Catholic Church for his view of the cosmos based on the theory of Copernicus. Galileo was condemned by the Catholic Church for his view of the cosmos based on the theory of Copernicus.

2. Galileo Galilei’s Telescope Galileo used the telescope to observe spots on the sun and moon Galileo used the telescope to observe spots on the sun and moon –Discredited the Ptolemaic notion that the heavenly bodies are smooth, immaculate, unchanging and perfectly spherical Galileo’s drawing of the moon showing craters

3. Galileo Galilei Other achievements: Other achievements: –Noticed four of the moons that orbit Jupiter –Observed previously unknown distant stars –Meant universe is much larger than previously suspected –Showed that the velocity of falling bodies depends not on their weight but on the height from which they fall Galileo’s telescope However, Galileo was unable to clearly resolve Saturn’s rings!

4. Galileo’s Books Galileo published his discoveries and support for the Copernican model in two books published in 1616 and 1632. Galileo published his discoveries and support for the Copernican model in two books published in 1616 and 1632. Galileo was unusual for the time because he wrote in Italian rather than Latin like most scholars. Galileo was unusual for the time because he wrote in Italian rather than Latin like most scholars. Galileo also took great pains to make his books interesting often writing them in the form of dialogues rather than dry, boring dissertations. Galileo also took great pains to make his books interesting often writing them in the form of dialogues rather than dry, boring dissertations. After his first book, "Starry Messenger", was published he was warned by the Church not to publicly support Copernicism again. After his first book, "Starry Messenger", was published he was warned by the Church not to publicly support Copernicism again.

5. Galileo Galilei In 1632, he published his Dialogue Concerning the Two Chief World Systems which compares the Copernican and Ptolemaic systems In 1632, he published his Dialogue Concerning the Two Chief World Systems which compares the Copernican and Ptolemaic systems –Found guilty of heresy by the Spanish Inquisition and spent the rest of his life under house arrest Galileo’s Dialogue

6. Trial Before the Inquisition Galileo abided by this edict until 1632 when he published "A Dialogue on the Two Chief World Systems". This book's outright support for the Copernican model and its ridiculing of the Ptolemaic model earned Galileo a trial before the Inquisition. Galileo abided by this edict until 1632 when he published "A Dialogue on the Two Chief World Systems". This book's outright support for the Copernican model and its ridiculing of the Ptolemaic model earned Galileo a trial before the Inquisition. Galileo was accused of heresy and sentenced to house arrest for life. However, he got off easily compared to fellow Italian Giordano Bruno who was burned at the stake in 1600 for teaching Copernican ideas. Galileo was accused of heresy and sentenced to house arrest for life. However, he got off easily compared to fellow Italian Giordano Bruno who was burned at the stake in 1600 for teaching Copernican ideas.Giordano BrunoGiordano Bruno

7. In 1992, the Roman Catholic Church finally repealed the ruling of the Inquisition against Galileo. The Church gave a pardon to Galileo and admitted that the heliocentric theory was correct. This pardon came 350 years after Galileo's death. In 1992, the Roman Catholic Church finally repealed the ruling of the Inquisition against Galileo. The Church gave a pardon to Galileo and admitted that the heliocentric theory was correct. This pardon came 350 years after Galileo's death.

8. Why are scientists against the Ptolemaic Model of the Solar System? Today, scientists have evidence of Earth’s orbital motion around the sun. Additionally, the rotation on its axis provides seasons, which work against the early Ptolemaic model. Today, scientists have evidence of Earth’s orbital motion around the sun. Additionally, the rotation on its axis provides seasons, which work against the early Ptolemaic model.

9. On what did Copernicus and Ptolemy agree? Both Copernicus’ heliocentric and the Ptolemaic models agreed on the need for epicycles. These were miniature orbits that the celestial bodies travelled on as well as their normal orbits. Copernicus, like Ptolemy, still put these bodies orbiting in perfect circles and had to put these in to explain some of the movements of the planets. Both Copernicus’ heliocentric and the Ptolemaic models agreed on the need for epicycles. These were miniature orbits that the celestial bodies travelled on as well as their normal orbits. Copernicus, like Ptolemy, still put these bodies orbiting in perfect circles and had to put these in to explain some of the movements of the planets.

10. Long ago, people probably observed the heavens because… They used the motion of the stars to guide their calendars and to keep track of time. They used the motion of the stars to guide their calendars and to keep track of time.

11. The Ptolemaic model of the universe explained planet motions using Epicycles – assuming that each planet moved on a small sphere or circle Epicycles – assuming that each planet moved on a small sphere or circle These Epicycles moved around a larger sphere called a deferent These Epicycles moved around a larger sphere called a deferent

12. The Ptolemaic model of the universe explained planet motions using http://www.polaris.iastate.edu/EveningStar/Unit2/unit2_sub1.htm http://www.polaris.iastate.edu/EveningStar/Unit2/unit2_sub1.htm http://www.polaris.iastate.edu/EveningStar/Unit2/unit2_sub1.htm

13. What were the many contributions made by Galileo to astronomy using a telescope? His contributions to observational astronomy include the improving the telescope, telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter, named the Galilean moons in his honour, and the observation and analysis of sunspots. Galileo also worked in applied science and technology, improving compass design. His contributions to observational astronomy include the improving the telescope, telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter, named the Galilean moons in his honour, and the observation and analysis of sunspots. Galileo also worked in applied science and technology, improving compass design.

14. The Copernican heliocentric model was actually first proposed by: The Heliocentric theory was first proposed about 2300 years ago, by Aristarchus of Samos (310-230 BC). The Heliocentric theory was first proposed about 2300 years ago, by Aristarchus of Samos (310-230 BC).

15. More Precisely 2-1: Some Properties of Planetary Orbits Semimajor axis and eccentricity of orbit completely describe it Perihelion: closest approach to Sun Aphelion: farthest distance from Sun

16. 2.6 The Dimensions of the Solar System Astronomical unit: mean distance from Earth to Sun First measured during transits of Mercury and Venus, using triangulation

17. 2.6 The Dimensions of the Solar System Now measured using radar: Ratio of mean radius of Venus’s orbit to that of Earth very well known

18. Escape Velocity the speed needed to "break free" from the gravitational attraction of a massive body, without further propulsion, i.e., without spending more fuel. the speed needed to "break free" from the gravitational attraction of a massive body, without further propulsion, i.e., without spending more fuel.

19. Must Venus always lie between the Earth and the Sun in the Copernican theory? According to the Ptolemaic system, Venus could only display a crescent phase because its epicycle put it always in between Earth and the sun. According to the Ptolemaic system, Venus could only display a crescent phase because its epicycle put it always in between Earth and the sun. The Copernican system put everything rotating around the sun, and in this way it explained the phases of Venus. The Copernican system put everything rotating around the sun, and in this way it explained the phases of Venus.

20. Geosynchronous Orbits Orbit around Earth with orbital period of 1 sidereal day. Orbit around Earth with orbital period of 1 sidereal day. Circular Earth geosynchronous orbits have a radius of 42,164 km (26,199 mi). Circular Earth geosynchronous orbits have a radius of 42,164 km (26,199 mi). orbits with the same period always share the same semi-major axis orbits with the same period always share the same semi-major axis

21. Geosynchronous Orbits Orbit around Earth with orbital period of 1 sidereal day. Orbit around Earth with orbital period of 1 sidereal day. Circular Earth geosynchronous orbits have a radius of 42,164 km (26,199 mi). Circular Earth geosynchronous orbits have a radius of 42,164 km (26,199 mi). orbits with the same period always share the same semi-major axis orbits with the same period always share the same semi-major axis