1. Solar System Mr. Skirbst Physical Science Topic 27

2. http://www.nineplanets.org/

3. Nebular Theory -Solar System began as a huge cloud of dust and gas called a nebula

4. Nebular Theory -Solar System began as a huge cloud of dust and gas called a nebula -This nebula condensed to form the sun and planets while spinning around the center

5. Sun Formation -Protosun – “developing sun”

6. Sun Formation -Protosun – “developing sun” -Most gas gathered in center of nebula (place of greatest gravity)

7. Sun Formation -Protosun – “developing sun” -Most gas gathered in center of nebula (place of greatest gravity) -Nuclear fusion begins (star is “born”)

8. Planet Formation Protoplanet – “developing planet”

9. Planet Formation Protoplanet – “developing planet” -smaller clumps of matter gathered and formed, orbiting sun

10. Planet Formation Protoplanet – “developing planet” -smaller clumps of matter gathered and formed, orbiting sun -Inner Planets – “rocky” (most gasses burned off)

11. Planet Formation Protoplanet – “developing planet” -smaller clumps of matter gathered and formed, orbiting sun -Inner Planets – “rocky” (most gasses burned off) -Outer Planets – “gas giants” (cooler temperatures)

12. Planets Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto (now called a Dwarf Planet)

13. Planetary Motion “Planet” – Greek for “wanderer”

14. Planetary Motion “Planet” – Greek for “wanderer” Earth-centered System: Ptolemy, Greece 2 nd century AD

15. Planetary Motion “Planet” – Greek for “wanderer” Earth-centered System: Ptolemy, Greece 2 nd century AD Sun-centered System: Copernicus, 1500’s (planets orbit the sun, not Earth)

16. Planetary Motion Elliptical orbits: Johannes Kepller, 1500’s (first to suggest planets orbit in ellipses) Inertia + Gravity: Isaac Newton, 1600’s two forces at work with planets

18. Planetary Motion Orbit: path around object takes when moving around another object in space Inertia: motion of object will not change unless acted upon by a force

19. Planetary Motion Gravity: force attracting two objects with mass Period of Revolution: one orbit around sun Period of Rotation: one turn on axis