1. Charles Hakes Fort Lewis College1 Photos

2. Charles Hakes Fort Lewis College2 Chapter 4 Debris

3. Charles Hakes Fort Lewis College3 Misc Notes Drop in homework/study/review session is 2:30 Thursdays. Use it or lose it. “Regular” lab meetings this week. Solar System models (v2)

4. Charles Hakes Fort Lewis College4 Movie comments l Martian atmosphere l Asteroid density

5. Charles Hakes Fort Lewis College5 Asteroid Density How close are the Asteroids to each other?

6. Charles Hakes Fort Lewis College6 Chapter 4, 5 Debris - Asteroids and Comets

7. Charles Hakes Fort Lewis College7 Debris Asteroids Mostly between Mars and Jupiter. Silicate (rocky) predominate inner region Carbonaceous more common as you move out Meteoroids - Little Asteroids Micrometeoroids - Really little ones (dust) Often follow comet paths Comets - Dirty Snowballs

8. Charles Hakes Fort Lewis College8 Chapter 4 Asteroid Eros

9. Charles Hakes Fort Lewis College9 Asteroids (Minor Planets) Most are in the “Asteroid belt” between Mars (1.5 AU) and Jupiter (5.2 AU). Largest is Ceres (940 km in diameter). Orbits generally more elliptical than planets Trojan asteroids - in stable orbits 60° ahead of and behind Jupiter.

10. Charles Hakes Fort Lewis College10 Figure 4.4 Inner Solar System

11. Charles Hakes Fort Lewis College11 Figure 4.6 Asteroid Images

12. Charles Hakes Fort Lewis College12 Figure 4.7 Asteroid Eros

13. Charles Hakes Fort Lewis College13 Asteroid Density How close are the Asteroids to each other?

14. Charles Hakes Fort Lewis College14 Asteroid Density How close are the Asteroids to each other? Number of known asteroids ~100,000. Distance from sun 2-4 A.U.

15. Charles Hakes Fort Lewis College15 Asteroid Density How close are the Asteroids to each other? Number of known asteroids ~100,000. Distance from sun 2-4 A.U. Area ~  (4AU) 2 -  (2AU) 2 = 8.5x10 17 km 2 Say there are really lots more… (~1,000,000,000) Then each one still gets 8.5x10 8 km 2

16. Charles Hakes Fort Lewis College16 Asteroid Density How close are the Asteroids to each other? Number of known asteroids ~100,000. Distance from sun 2-4 A.U. Area ~  (4AU) 2 -  (2AU) 2 = 8.5x10 17 km 2 Say there are really lots more… (~1,000,000,000) Then each one still gets 8.5x10 8 km 2 Distance = 3x10 4 km (~2.5x diameter of Earth)

17. Charles Hakes Fort Lewis College17 Asteroids (Minor Planets) Over 2000 Earth-crossing asteroids are known.

18. Charles Hakes Fort Lewis College18 Discovery 4-1a What Killed the Dinosaurs?

19. Charles Hakes Fort Lewis College19 Figure 4.15 Barringer Crater (near Winslow, AZ ~25,000 years ago)

20. Charles Hakes Fort Lewis College20 Figure 4.17 Tunguska Debris (Siberia, 1908)

21. Charles Hakes Fort Lewis College21 Figure 4.16 Manicouagan Reservoir (~200,000,000 years ago)

22. Charles Hakes Fort Lewis College22 Discovery 4-1b What Killed the Dinosaurs?

23. Charles Hakes Fort Lewis College23 Figure 4.18 Meteorite Samples a) stony silicate b) iron

24. Charles Hakes Fort Lewis College24

25. Charles Hakes Fort Lewis College25 This is: A) A natural rock outcropping B) New FLC Landscaping C) Something else

26. Charles Hakes Fort Lewis College26 Comets Dirty snowballs

27. Charles Hakes Fort Lewis College27 Comets Nucleus Dirty Snowballs - “dirt” accumulates on surface Often only a few km in diameter Coma Bright part around the nucleus Could be 100,000 km in diameter Tail Could be up to 1 A.U. in length! Ion Tail - points directly away from the Sun Dust Tail - points away from Sun, but “drags” a bit. Hydrogen Envelope - surrounds all, but not visible

28. Charles Hakes Fort Lewis College28 Figure 4.8 Halley ’ s Comet

29. Charles Hakes Fort Lewis College29 Figure 4.9 Comet Tails a) Giacobini-Zinner b) Hale-Bopp (1997)

30. Charles Hakes Fort Lewis College30 Figure 4.10 Comet Trajectory

31. Charles Hakes Fort Lewis College31 Figure 4.11 Halley ’ s Comet Closeup from Giotto spacecraft

32. Charles Hakes Fort Lewis College32 Figure 4.12 Comet Reservoirs Oort Cloud huge spherical reservoir of long period comets Kuiper Belt outside the orbit of Neptune in plane of solar system reservoir of short period comets e.g. Haley’s comet

33. Charles Hakes Fort Lewis College33 Figure 4.14 Meteor Showers

34. Charles Hakes Fort Lewis College34 Figure 4.13 Meteor Trails

35. Charles Hakes Fort Lewis College35 Three Minute Paper Write 1-3 sentences. What was the most important thing you learned today? What questions do you still have about today’s topics?

36. Charles Hakes Fort Lewis College36 Gravity Review

37. Charles Hakes Fort Lewis College37 Gravity Review Exercise You build a tower 1000 km high, and weigh yourself on top. Note that this is 3 times as high as the Space Station flies. Calculate how much you would you “weigh” (Force between you and the Earth in Newtons), and compare to your homework.

38. Charles Hakes Fort Lewis College38 Related Questions Why would someone in the Space Station feel no weight?

39. Charles Hakes Fort Lewis College39 Related Questions Why would someone in the Space Station feel no weight? What would it feel like in a very tall elevator if the cable were cut?

40. Charles Hakes Fort Lewis College40 Related Questions Why would someone in the Space Station feel no weight? What would it feel like in a very tall elevator if the cable were cut? This is why the spring contracts - both the cup and spring are falling at the same rate. “Freefall” is a much more descriptive term than “weightless.”

41. Charles Hakes Fort Lewis College41 Three Minute Paper Write 1-3 sentences. What was the most important thing you learned today? What questions do you still have about today’s topics?