1. Chapter 4 Nebular HypothesisHypothesis for the Origin of our solar system…..4.6 bya, a rotating cloud of gas/dust shrank under its own gravity …..began rotating faster, thus forming a center

2. Con’t.That center compressed and became so hot that hydrogen fusion occurred. Thus our sun was born Earth formed out of condensing solid particle of ice and rock

3. Earth’s Shape Oblate spheroidFlattened at the poles and bulging at the equator Why? Due to earth’s spinning motion

4. Earth’s Structure Earth’s layersInner core (solid) Outer core (liquid) Mantle (solid) Crust (outermost layer)

5. Earth’s Heat Earth is heated from within Earth is slowly losing heat Compressed inner layers are very hot (6000 o K!) Radioactive decay of isotopes Earth’s crust in thinner in certain areas Certain types of rock retain heat better than others

7. Earth’s magnetic fieldWhy compass’s point north!!!!! The North pole attracts while the south pole repels Theory is that the field is created by moving liquid iron in the outer core

8. Because of Earth’s magnetic field… Auroras!!!Solar Wind (flow of electrically charged particles) comes into contact with Earth’s magnetic field and a bright, colorful light is created Aurora Borealis!!!!!