Exam 1 Results

2. Exam 1 Results

3. Kepler’s Laws of Motion More in-depth (Get out your ABCD cards!)

4. Copernicus (1473 – 1543 AD) is known for : First observations of the sun First Sun-centered model of the solar system or universe The world’s best naked-eye astronomical observations in history Creating the first theoretical model to explain planetary motions Creating the first theoretical model for explaining gravity

5. Copernicus (1473 – 1543 AD) is known for : First observations of the sun First Sun-centered model of the solar system or universe The world’s best naked-eye astronomical observations in history Creating the first theoretical model to explain planetary motions Creating the first theoretical model for explaining gravity

8. Johannes Kepler 1571 - 1630 is Known for - First telescope observations of the sun First Sun-centered scientific model of the solar system or universe Being the world’s best naked-eye astronomer Creating the first theoretical model to explain planetary motions Creating the first theoretical model for explaining gravity

9. Johannes Kepler 1571 - 1630 is Known for - First telescope observations of the sun First Sun-centered scientific model of the solar system or universe Being the world’s best naked-eye astronomer Creating the first theoretical model to explain planetary motions Creating the first theoretical model for explaining gravity

10. Review: Heliocentric Model 1543: Published his ideas to contest the Ptolemaic model Motions still follow perfect circles, but now Sun is at the center. Model was still rejected due to inaccuracy

11. Review Copernicus’ Errors The planets move in perfect circles The planets move at constant speeds The Sun is at the center of the orbits Kepler’s Corrections The planets move in orbits that are elliptical The planets continuously vary their speed The Sun is not quite at the center of the orbits

12. Kepler’s Laws of Planetary Motion The planets orbit along elliptical paths, with the Sun at one focus Draw these out on the boardDraw these out on the board

13. Kepler’s First Law:Planets Orbit the Sun along Ellipses.

14. Kepler’s First Law:Planets Orbit the Sun along Ellipses.

15. Large eccentricity ? More ovular Small eccentricity ? More circular Large eccentricity ? More ovular Small eccentricity ? More circular

16. Orbital Shape of Mercury Mercury’s orbit is the black line on the blue perfect circle eccentricity = 0.25 e = sqrt(1-(b^2/a^2))e = sqrt(1-(b^2/a^2))

17. Define perihelion, aphelion, perigee, apogee Sun images show up before Moon imagesDefine perihelion, aphelion, perigee, apogee Sun images show up before Moon images

18. Kepler’s Laws of Planetary Motion The planets orbit along elliptical paths, with the Sun at one focus A line connecting the Sun and a planet sweeps out equal areas during equal intervals of time Draw these out on the boardDraw these out on the board

20. Get out your ABCD cards!

21. Changes in orbital speedWhat causes an orbiting planet to move faster as it gets nearer the Sun? The equant Gravity The planet’s initial velocity How tipped its orbit is compared to the Sun’s equator BB

23. Kepler’s Laws of Planetary Motion The planets orbit along elliptical paths, with the Sun at one focus A line connecting the Sun and a planet sweeps out equal areas during equal intervals of time The orbital period of a planet is proportional to the semi-major axis of the orbit by the relation: p2 = a3 Draw these out on the boardDraw these out on the board

24. Kepler’s Third Law

25. Generalized Kepler’s Third Law M_sun = 2 x 10^30 kg = 333,000 x M_earth M_earth = 6 x 10^24 kg **For star/planet systems, basically mass-independent**M_sun = 2 x 10^30 kg = 333,000 x M_earth M_earth = 6 x 10^24 kg **For star/planet systems, basically mass-independent**

26. Kepler’s 3rd Law

27. Do a few math examples on the board Emphasize using parentheses correctly with calculator 0.39; 0.61; 1.52; 11.86Do a few math examples on the board Emphasize using parentheses correctly with calculator 0.39; 0.61; 1.52; 11.86

28. Get out your ABCD cards!

29. According to Kepler’s second law, a planet with an orbit like Earth’s would: A. move faster when further from the Sun. B. move slower when closer to the Sun. C. experience a dramatic change in orbital speed from month to month. D. experience very little change in orbital speed over the course of the year. E. none of the above. DD

30. Which of the following best describes what would happen to a planet’s orbital speed if its mass were doubled but it stayed at the same orbital distance? A. It would orbit half as fast. B. It would orbit less that half as fast. C. It would orbit twice as fast. D. It would orbit more than twice as fast. E. It would orbit with the same speed. EE

31. Kepler’s second law says “a line joining a planet and the Sun sweeps out equal areas in equal amounts of time.” Which of the following statements means nearly the same thing? A. Planets move fastest when they are moving toward the Sun. B. Planets move equal distances throughout their orbit of the Sun. C. Planets move slowest when they are moving away from the Sun. D. Planets travel farther in a given time when they are closer to the Sun. E. Planets move the same speed at all points during their orbit of the Sun. DD

32. If a small weather satellite and the large International Space Station are orbiting Earth at the same altitude above Earth’s surface, which of the following is true? A. The large space station has a longer orbital period. B. The small weather satellite has a longer orbital period. C. Each has the same orbital period CC

33. Reminder Homework #2 is due in one week Keep an eye on the weather! Come pick up your graded assignments in your corresponding folder