PSc 100D The Solar System

1. 0 PSc 100DThe Solar System Please pick up a transmitter (“clicker”) for the response system.

2. 0 PSc 100DThe 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. 0 General Information • Course Web Site: • http://www.phy.ohiou.edu/~mboett/PSC100D/winter09/PSC100D_winter09.html Link Check this web site regularly. All updates, reading and writing assignments, exam results, etc. will be posted on this web site

4. 0 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? • Planets • A star • A galaxy • Comets • Meteoroids

6. 0 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. 0 The Scale of the Cosmos • Astronomy deals with objects on avast range of size scales and time scales. • Most of these size and time scales areway beyond our every-day experience. • Humans, the Earth, andeven the solar system are tiny and unimportant on cosmic scales.

8. 0 A Campus Scene 16 x 16 m

9. 0 A City View 1 mile x 1 mile

10. 0 The Landscape of Pennsylvania 100 miles x 100 miles

11. 0 The Earth Diameter of the Earth: 12,756 km

12. Guess: How many times would you have to travel around the Earth to travel the distance between the Earth and the moon? • 2.1 • 9.6 • 26 • 745 • 1.38 million

13. 0 Earth and Moon Distance Earth – Moon:384,000 km

14. 0 Earth orbiting around the Sun Distance Sun – Earth = 150,000,000 km

15. 0 Earth orbiting around the Sun In order to avoid large numbers beyond our imagination, we introduce new units: 1Astronomical Unit (AU) = Distance Sun – Earth = 150 million km

16. How many miles are there in 1 AU? • 245,000 • 9.4 million • 93.7 million • 1.38 billion • 3.6 trillion

17. 0 The Solar System Approx. 100 AU

18. (Almost) Empty Space Around our Solar System 0 Approx. 10,000 AU

19. 0 The Solar Neighborhood Approx. 17 light years

20. 0 The Solar Neighborhood New distance scale: 1light year (ly)= Distance traveled by light in 1 year = 63,000 AU = 1013 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 • 1.5*108 km • 1.5*1010 km • 1.5*1015 km • 8*1015 km • 8*101.5 km

22. 0 The Extended Solar Neighborhood Approx. 1,700 light years

23. 0 The Milky Way Galaxy Diameter of the Milky Way:~ 75,000 light years Animation

24. The diameter of the Milky Way is • 7.5*103 light years • 7.5*104 light years • 7.5*105 light years • 5*107.5 light years • 57.5 light years

25. The Local Group of Galaxies 0 Galaxies usually don’t exist alone, but inclusters of galaxies Distance to the nearest large galaxies:several million light years

26. 0 The Universe on Very Large Scales Clusters of galaxies are grouped intosuperclusters. Superclusters formfilamentsand wallsaround voids.