1. Formation of Our Solar System

2. A. The solar Nebula
1. Concentrations of dust and gas start to collect in the center of the nebula

3. 2. Gravity, heat, and pressure increase RAPIDLY

4. 3. Nebula collapses under the immense gravity

5. 4. Large central mass begins rotating rapidly

6. 5. Nebula rotates so rapidly, that it begins to flatten out into a disk type shape.

7. 6. Rapid rotation and collection of central gasses continues for ~ 10 million years

8. 7. Gravity and friction produce heat hot enough to fuse hydrogen atoms, and The Sun is born!!

9. B. Formation of inner planets
1. Metallic elements (Mg, Si, Fe) condense into solids at high temperatures

10. 2. Like materials collide and stick to one another – process called accretion

11. 3. Heaviest materials move toward the center where the gravitational pull is the strongest

12. 4. Larger masses begin to develop a gravitational pull of their own.

13. a. Larger planetary bodies dominate, grow rapidly, and clean up surrounding areas of debris

14. C. Formation of Outer Planets
1. Made of ice and gasses. Temperatures are extremely cold

15. 2. 10x more particles than inner planets

16. 3. Early burst of solar wind sweeps remaining debris out of the solar system.

17. a. Beyond the gas giants are dwarf planets and the Kuiper Belt

18. D. Gravity in Space
1.  Every object in space exerts a gravitational pull

19. 2. Gravity pulls toward the center of a planet or star – this is why planets are round 

20. 3. Gravity influences the paths taken by everything moving through space.

21. 4. Orbits- perfect balance between forward motion (inertia) of an object, and the pull of gravity from another body in space

22. E. Asteroids, Comets, and Meteors
Asteroids - chunks of rock. Revolve around the sun between the orbits of Mars and Jupiter (asteroid belt)

23. a. Rock debris in asteroid belt should have formed into a planet, but Jupiter’s gravity and gravity within our solar system prevented this from happening

24. 2. Comets – chunks of ice and dust whose orbits are usually very long, narrow ellipses

25. a. Few pass near Earth, and they can only be seen briefly

26. b. As comets near the sun, some of the ice turns to liquid
b. As comets near the sun, some of the ice turns to liquid. This forms the comets “tail.”

27. c. Astronomer Edmond Halley (Halley’s Comet) discovered comets orbit much like planets.

28. 3. Meteors – chunk of rock or dust in space

29. Meteoroids – (stay in space)
Meteor – burns up in Earth’s atmosphere
Meteorite – strikes Earth’s surface.