1. Formation of the Solar System Week 5 (Welcome back from Spring Break)

2. Quick overview of the Solar System Space School: http://www.youtube.co m/watch?v=mtKNH2Y2 OJM&feature=related http://www.youtube.co m/watch?v=mtKNH2Y2 OJM&feature=related

3. Theories of How the Solar System Formed Target 1: Summarize the major features that a theory of solar system origins has to explain. All theory's of how the solar system formed must explain observations of composition, motion, and organization of the objects in the solar system. YouTube Video: Astropedia http://www.youtube.com/watch?v=l82OYfeDWqY&feature=bf _prev&list=PLA021BE54103940FE&lf=plpp_video

4. TERRESTRIAL vs GIANT PLANETS The inner planets are smaller and denser than the outer planets, and are made of silicates and metals. In contrast, the outer planets are dominated by hydrogen and have many satellites that are rich in water ice and other volatiles. DIFFERENTIATION!!!!

5. PROGRADE ROTATION All planets move around the Sun in the same direction that the Sun rotates and close to the equatorial plane of the Sun. Visit this animation to observe the motions of the objects in the solar system. http://janus.astro.umd.edu/javadir/orbit s/ssv.html

6. Angular Momentum Mass and Angular Momentum Although the Sun has 99.98% of the mass in the solar system, the planets have 99.7% of the system’s angular momentum. This means that most of the “spin” in the solar system comes from the planets! Definition Angular Momentum: is a vector quantity that can be used to describe the overall state of a physical system. Linear Momentum: p = mv

7. Angular Momentum: Try this at home!

8. Angular Momentum, L L = mvr L = angular momentum m = mass v = velocity r = radius Which one of these variable changed in your spinning seat experiment?

9. Angular Momentum of a system is Conserved in the Universe! One of Brian Boitano’s crowd- pleasing skating moves involves initiating a spin with his arms extended and then moving his arms closer to his body. As he does so, he spins at a faster and faster rate. Which of the following laws best explains this phenomenon? (A) Conservation of Mechanical Energy (B) Conservation of Angular Momentum (C) Conservation of Linear Momentum (D) Newton’s First Law (E) Newton’s Second Law

10. Angular Momentum is Conserved Professor Brian Cox provides a preview of the winning theory of the formation of the solar systems and how angular momentum plays an important role: http://www.youtube.com/ watch?v=zzGxbFVOX1A &feature=related

11. RETROGRADE PLANETS Despite the general regularity of planetary orbital spin motion, Venus, Uranus and Pluto all spin in a retrograde direction. Read Handout: Retrograde Rotation

12. Tilt of Planets on their Axes Why do the planets have tilts?

13. The asteroids have compositions intermediate between the rock & metal rich inner planets and the volatile-rich outer solar system, and are located between the orbits of Mars and Jupiter.

14. The oldest and most primitive meteorites contain grains of compounds that are expected to have formed in a cooling cloud of cosmic abundance at temperatures of a few hundred degrees.

15. The oldest rock age recorded in the solar system is 4.5 billion years old.

16. COMETS Comets, like the surface of some outer planet satellites, appear to be composed primarily of water ice, with significant quantities of trapped or frozen gases like carbon dioxide, plus silicate dust.

18. Volatiles Volatile compounds (such as water) must have reached the inner planets in spite of the fact that he bulk composition of these bodies suggests formation at temperatures too high for volatiles to form solid grains

19. Irregular Satellites All the giant planets have systems of regular satellites orbiting in their equatorial planes, rather like miniature versions of the solar system.

20. Regular Satellites: Uranus Except Uranus, the giant planets have one or more irregular satellite that have an orbit that is either retrograde or have high inclinations or eccentricities.

21. What is the solar system made of? Where did that material come from? Why is the solar system rotating? How did the planets form? Why are there some terrestrial planets and some gaseous or icy? And why are they where they are? Why do some planets have moons? How old is the solar system?

22. The Condensation Theory The most widely accepted theory of the formation of our own solar system and other planetary systems. Reading: The Condensation Theory - Nebular Contraction http://lifeng.lamost.org/courses/astrotoday/CH AISSON/AT315/HTML/AT31502.HTM

23. Overview Collapse of a nebula (a) Conservation of angular momentum demands that a contracting, rotating cloud (a) must spin faster as its size decreases. (b) Eventually, the primitive solar system came to resemble a giant pancake. The large blob at the center would ultimately become the Sun.

25. Condensation and Accretion Reading: Differentiation in the Solar System – The Role of Heat http://lifeng.lamost.org/courses/astrotoday/CHAISSON/AT315/HTML/AT31503.HTM http://lifeng.lamost.org/courses/astrotoday/CHAISSON/AT315/HTML/AT31503.HTM

27. Age of the Solar System

28. http://www.youtube.com/watch?v=UcaZfWa NR64&feature=fvsr http://www.youtube.com/watch?v=UcaZfWa NR64&feature=fvsr

29. Fun Friday The History Channel - The Universe: How the Solar System was Made http://www.youtube.com/watch?v=Wj- OWGHYxLg&feature=related

30. Learning Targets Summarize the major features that a theory of solar system origins has to explain. Outline the process by which planets form as natural by-products of star formation. Explain the role played by dust in the currently accepted model of solar system formation. Account for the differences between the terrestrial and the jovian planets. Discuss the role of collisions in determining specific characteristics of the solar system. Explain the angular momentum problem and discuss some proposed solutions. Discuss the role of meteorites and radioactive dating to determine the current age of the solar system.

31. Review with Questions http://lifeng.lamost.org/courses/astrotoday/C HAISSON/AT315/HTML/AT315EOC.HTM http://lifeng.lamost.org/courses/astrotoday/C HAISSON/AT315/HTML/AT315EOC.HTM Reference: http://lifeng.lamost.org/courses/astrotoday/CH AISSON/AT315/HTML/AT31500.HTM