1. PSc 100D The Solar System Please pick up a transmitter (“clicker”) for the response system.

2. PSc 100D The Solar System Associate Professor M. Böttcher Clippinger Hall #339 Phone: 593 1714 E-mail: boettchm@ohio.edu Office Hours: Mo., Tu., We., Th., 5:00 p.m. – 6:00 p.m.

3. General Information Course Web Site: http://www.phy.ohiou.edu/~mboett/PSC100D/winter09/PSC100D_winter09.html Check this web site regularly. All updates, reading and writing assignments, exam results, etc. will be posted on this web site Link

4. The Response System We will use the personal response system (PRS) for questions + answers throughout the lectures (Mo. – We.). Class participation during regular lectures will enter with 10 % into the final class grade. Also used for 6 Reasing Assignment Quizzes almost every Thursday. Scores of Reading Assignment Quizzes will be combined to 30 % of your final class grade.

5. Example: Which of the following is not a part of the solar system? 1.Planets 2.A star 3.A galaxy 4.Comets 5.Meteoroids

6. As a Matter of Courtesy Please turn your cell phones off or on vibrating mode during the lectures If you really need to leave during the lecture, do so quietly, through the rear door of the lecture hall.

7. The Scale of the Cosmos Astronomy deals with objects on a vast range of size scales and time scales. Most of these size and time scales are way beyond our every-day experience. Humans, the Earth, and even the solar system are tiny and unimportant on cosmic scales.

8. 16 x 16 m A Campus Scene

9. 1 mile x 1 mile A City View

10. 100 miles x 100 miles The Landscape of Pennsylvania

11. Diameter of the Earth: 12,756 km The Earth

12. Guess: How many times would you have to travel around the Earth to travel the distance between the Earth and the moon? 1.2.1 2.9.6 3.26 4.745 5.1.38 million

13. Distance Earth – Moon: 384,000 km Earth and Moon

14. Distance Sun – Earth = 150,000,000 km Earth orbiting around the Sun

15. In order to avoid large numbers beyond our imagination, we introduce new units: 1 Astronomical Unit (AU) = Distance Sun – Earth = 150 million km

16. How many miles are there in 1 AU? 1.245,000 2.9.4 million 3.93.7 million 4.1.38 billion 5.3.6 trillion

17. Approx. 100 AU The Solar System

18. Approx. 10,000 AU (Almost) Empty Space Around our Solar System

19. Approx. 17 light years The Solar Neighborhood

20. New distance scale: 1 light year (ly) = Distance traveled by light in 1 year = 63,000 AU = 10 13 km = 10,000,000,000,000 km (= 1 + 13 zeros) = 10 trillion km Nearest star to the Sun: Proxima Centauri, at a distance of 4.2 light years Approx. 17 light years

21. 1 AU (= 150 million = 150,000,000 km) equals 1.1.5*10 8 km 2.1.5*10 10 km 3.1.5*10 15 km 4.8*10 15 km 5.8*10 1.5 km

22. Approx. 1,700 light years The Extended Solar Neighborhood

23. Diameter of the Milky Way: ~ 75,000 light years The Milky Way Galaxy Animation

24. The diameter of the Milky Way is 1.7.5*10 3 light years 2.7.5*10 4 light years 3.7.5*10 5 light years 4.5*10 7.5 light years 5.5 7.5 light years

25. Distance to the nearest large galaxies: several million light years The Local Group of Galaxies Galaxies usually don’t exist alone, but in clusters of galaxies

26. Clusters of galaxies are grouped into superclusters. Superclusters form filaments and walls around voids. The Universe on Very Large Scales