Download Name_________________________ 1 AST 101 Ancient

Name_________________________ AST 101 Ancient Astronomy Worksheet Due Wed, 2/19 WORTH 2 QUIZ GRADES 1. Briefly describe the geocentric model: The Sun, Moon, planets, and stars all orbit around the Earth. 1 pt 2. How did the Ptolemaic model differ from the simple geocentric model? Ptolomy took retrograde motion into account using epicycles—small circles around which the planets orbit as they went around the Earth. 1 pt 3. Briefly describe the heliocentric model: The planets and Earth orbit the Sun. The Moon orbits the Earth. 1 pt 4. List the objections to the heliocentric model, and beside each objection describe an observation by Galileo that helped resolve the objection. Objection Observation noncircular orbits are not perfect the Moon has mountains, the Sun has spots à the heavens are not perfect If the Earth was moving, objects like the Discovery of Jupiter’s Moons Moon would get left behind Jupiter is moving and its moons are not left behind If the Earth was moving, we would see Stars are far away, so parallax should stellar parallax not occur 4 points Note: the phases of Venus showed that it was moving around the Sun and do NOT address any specific objections to Kepler’s model 1 Name_________________________ 5. In one or two paragraphs, describe how the characteristics of science listed on slide two apply to the process of developing a theory for the motion of planets in our solar system. The characteristics of science describe the process of science: first, observations are made. These observations lead to a hypothesis, which is then described and tested by models. If the models do not fit the observations, the old hypothesis and models are replaced by new, better models. We can see this in the theory of motion of planets in the Solar System: first, the geocentric model was proposed. Then, retrograde motion was observed, and the geocentric model was revised and replaced with the Ptolemaic model. Finally, after hundreds of years, the observations improved again, and the Ptolemaic model was replaced with the heliocentric model. The heliocentric model was revised by Kepler, and it is the best model that fits the data today. 3 pts 2