Chapter 2 Earth: A Unique Planet What Makes The Earth So Unique Liquid water on its surface Atmosphere that contains 21% Oxygen Supports Life Chapter 2 Earth Basics Characteristics of a unique Earth •Third planet from the sun •Formed about 4.6 billion years ago •Made mostly of Rock •71% is covered with global oceans •Color- Blue-Oceans, Green/Brown-Continents. White-Clouds or Ice Caps •Shape Oblate Spheroid •Size-Equatorial circumference 24,000 mi, speed of rotation 1,000 mph •Earth’s surface is relatively smooth; Everest 29,000 ft, Mariana's Trench 35,000 ft deep Chapter 2 Earth’s Interior The Earth’s interior can be indirectly observed using seismic waves. Seismic Waves- vibrations that travel through the Earth. Compositional Zones Crust- Thin, solid, outer most layer •Makes up 1% of Earth’s mass •Oceanic crust- 5-10 km thin, dense •Continental crust- 15-80 km, thickest beneath mountains. Mantle- Solid to semi-solid layer of the Earth that lies between the crust and core. •2,900 km thick •Makes up 66% of the Earth’s mass Outer Core- Hot, liquid layer located between the mantle and the inner core. •Liquid Rock •High Temperature •Iron (Fe), Nickel (Ni) Inner Core- Very hot, solid layer located in the center most part of the Earth. •Very Hot •High Pressure •Made of Iron (Fe), Nickel (Ni) Compositional Structure of the Earth Structural Zones of the Earth Lithosphere- solid, outer layer of Earth that consist of the crust and upper mantle. Asthenosphere- solid, semi-solid, plastic layer of the mantle beneath the lithosphere. Mesosphere- middle sphere, located in the lower part of the mantle, between the asthenosphere and outer core. Earth’s Magnetic Field The Earth has two magnetic poles; North magnetic pole and the South magnetic pole. Earth’s Magnetic Field- A charged field that extends from pole to pole, creating a field or magnetosphere which protects the Earth from charged particles from the sun. Magnetic Field- The Earth's surface and its inhabitants are protected from dangerous cosmic radiation (energetic protons) from the Sun by the Earth's magnetic field. Earth’s Gravity Gravity- is the force of attraction between all matter in the universe. Newton’s (17th-century) Laws of gravitation- the force of attraction between any two objects depends on the masses of the objects and the distance between the objects. The larger the objects and the closer they are together the stronger the gravitational force. Mass- total amount of matter. Weight- a measure of the strength of the pull of gravity on an object. •The closer you are to the center of the Earth, the stronger the pull.