Chapter 27.1 Notes Formation of the Solar System

1. Chapter 27.1 NotesFormation of the Solar System Std. 1b- Know the evidence from Earth and moon rocks indicates that the solar system was formed from a nebular cloud of dust and gas approx. 4.6 billion years ago Std. 1c- Know the evidence from geological studies of Earth and other planets suggest that the early Earth was very different from Earth today Objective 1:Explain the origin of the solar system Objective 2: Describe how the planets formed Objective 3: Describe the formation of the land, the atmosphere and the oceans of Earth

2. Solar system - is the sun and all the planets and other bodies that revolve around the sun • Matter is spread out throughout the universe • Some matter gathers into a cloud of dust known as a nebula • The Nebular Hypothesis explains the origins of the solar system

3. The Nebular Hypothesis • Solar nebula - the sun and the planets formed from a rotating cloud of gas and dust • Energy from collisions and pressure from gravity caused the center of the nebular to become hotter and denser

4. Hydrogen fusion began when temperatures at the center became 10,000,000⁰C forming a star (sun) • Sun = 99% of all the matter that was contained in the solar nebula

5. Formation of the Planets • The sun was forming in the center & planets were forming in the outer regions • Planetesimals- small bodies from which planet originates • Collisions formed protoplanets which become planets and moons • Moons orbit planets

6. Objective 1:Explain the origins of the solar system • Solar systems form from a cloud of gas and dust known as a… • Nebula • The sun makes up what % of the solar nebula? • 99% • Small bodies from which planets originate are known as… • Planetesimals

7. Formation of the Inner Planets • Formation of the planets depended on the distance to the developing sun • The 4 inner planets are: • Mercury • Venus • Earth • Mars

8. Inner planets contained large amounts of heavy elements (iron & nickel)- denser materials sank to the center • Less dense gases were boiled or blown away by sun’s radiation • Inner planets are rockier and denser than outer planets

9. Formation of the Outer Planets • The outer planets are: • Jupiter • Saturn • Uranus • Neptune • They formed in the outer (colder) region of the solar nebular • did not lose their lighter elements (helium, hydrogen) and ices

10. Ices (water, methane, ammonia) melted forming layers of liquids and gases • Outer planets known as Gas Giants are made of mostly gases, low density and huge

11. The Different Planet - Pluto • Farthest from the sun • Smaller than the Earth’s moon • Ice ball made of frozen gases & rock • Not considered a planet anymore

12. Objective 2:Describe how the planets formed • What are the 4 inner planets? • Mercury, Venus, Earth, Mars • What 2 elements make up the inner planets? • Nickel and Iron • What are the 4 outer planets? • Jupiter, Saturn, Uranus, Neptune • What are 3 compounds make up the outer planets? • Water, methane and ammonia • Outer planets are also known as… • Gas giants

13. Formation of Solid Earth Early Solid Earth • Young Earth was hot enough too melt iron • Differentiation - denser material sank to the center, less dense formed the outer layers • Differentiation caused distinct layers. • Core, Mantle, Crust

14. Present Solid Earth • Earth’s surface eventually cooled enough for solid rock to form • Surface continues to change/move due to the heat of Earth’s interior

15. Formation of Earth’s Atmosphere • Formed because of differentiation • Less dense gas molecules (hydrogen & helium) rose to the surface

16. Earth’s Early Atmosphere • Earth’s gravity could not hold these gases (hydrogen & helium) • they may have been blown away by a much stronger solar wind than today

17. Outgassing • Outgassing - Volcanic eruptions released large amounts of water vapor, carbon dioxide, nitrogen, methane etc. • formed a new atmosphere

18. Earth’s Present Atmosphere • Early green plants released oxygen during photosynthesis • About 2 billion years ago, the % of oxygen increased rapidly • Composition of the atmosphere has been similar to today’s

19. Formation of Earth’s Oceans • Water may have been from space • Icy bodies, such as comets collided with Earth • Water condensed to form rain • The first oceans were probably fresh water • Over millions of years, rain water dissolved solids (salts) from rocks and added the salts into the ocean

20. Objective 3: Describe the formation of the land, the atmosphere and the oceans of Earth • What process caused distinct layers of the Earth to form? • Differentiation • What process formed a new atmosphere on Earth? • outgassing • How did Earth’s atmosphere get it’s oxygen? • Photosynthesis