1. ORIGINS Oceans & Continents Crust Earth Solar System Universe

2. Scientific Method Observations or experiments Hypotheses Testing Theories (Scientific Truths)

3. The Universe Planets Stars Galaxies Clouds of Dust & Gas Interstellar Space

4. Clouds of dust and gas in Eagle Nebula (Hubble Picture )

5. View of Galaxies in deep space from Hubble space telescope

6. Sombrero Galaxy

7. Andromeda Galaxy

8. Milky Way Galaxy

9. Origin of Universe Evidence All galaxies in universe appear to be moving away from one another (Red Shift in Starlight) The greater their distance the faster they are receding The temperature of interstellar space is not 0 o K but 2.7 o K Big Bang Theory

10. Origin of Solar System Evidence Astronomical observations of stars beyond solar system Observations of structure & composition of solar system Internal structure and composition of Earth

11. Star Formation in a Dust and Gas Cloud in Scorpius

12. Sun during eclipse

13. Solar Spectrum

14. The Sun Sun makes up 99.9% of Solar System Sun is mainly made of: Hydrogen (element #1, simplest and most abundant element in universe) Helium (element #2, second most abundant) Solar energy produced by nuclear fusion 4 Hydrogen nuclei = 2 Helium nuclei + energy

15. The Solar System With exception of Pluto, all planets occupy sub-circular orbits All orbit in the same plane (ecliptic) and in same direction Nearly all rotate in same direction about axes that are nearly perpendicular to ecliptic

16. The Planets Inner Planets Mercury, Venus, Earth, Mars Small, dense, rocky. Few moons Outer Planets Jupiter, Saturn, Uranus, Neptune Large, low density, icy. Many moons Pluto

17. Solar System and Outer Planets

18. Internal structure of Earth Atmosphere <1 g/cm 3 Hydrosphere 1 g/cm 3 Crust 2.7-2.9 g/cm 3 Mantle 3.3-5.6 g/cm 3 Core 10-14 g/cm 3 A Differentiated Planet

19. Nebular Theory Star systems are formed by the gravitational collapse of diffuse clouds of dust and gas (nebulae) Cold clouds of dust and gas (mainly hydrogen) are most abundant constituents of universe Gravitational collapse always leads to rising temperatures.