Formation of the Universe and Earth’s Interior 1

Do Now- Think about the following and respond in your journals:  How did the Universe form?  How did early Earth form?  Differentiate the following terms:  Stars  Planets  Sun  Solar system  Galaxy  Universe 2

Big Bang Theory  Inflation & Dark Energy  1929 Edwin Hubble discovered the expansion of the Universe with galaxies moving away from us  This suggested The Universe was born in a single violent event about 14 billion years ago  The Big Bang  Short period of a burst of expansion after the Big Bang  Inflation  Due to an unstable form of energy  Dark Energy  Mathematical models and scientific discoveries support The Big Bang & Inflation Theories  Galaxies are still moving away from Earth

The Earth’s resources were determined when the planet formed. Earth is ~4.6 b.y. old  Formed from gasses (H, He) and cosmic dust  Bombardment of debris from the sun  Early Earth was a hot, molten sphere “magma ocean” that cools from outside-in  Cooling  differentiation into layers based on elemental masses  Heavier elements sank towards center; lighter floated toward the surface…some to the atmosphere  Elements found on earth are as old as the planet; Unevenly distributed  Uneven distribution (concentration in areas) allows us to mine those resources.

Compositional (Chemical) Layers of the Earth  Crust  99% by mass; only 8 elements  O 2, Si, Al, Ca, Mg, Fe, Na, K  50% O 2 ; 25% Si  Silicates (SiO 4 ) Moho- Boundary b/w Crust & Mantle  Mantle  Silicates (SiO 4 )  Primarily Mg, Fe, Ca, Al CMB- Boundary b/w Core & Mantle  Core  Fe-Ni alloy

Physical Layers of the Earth Change in state; Dominated by temperature & pressure  Lithosphere  Brittle solid; Temp  Asthenosphere  Partially molten w/rock; Temp  Mesosphere  Plastic solid; Pressure  Outer core  Liquid; Temp  Inner core  Solid; Pressure There is an interplay of increasing T & P with depth

Layers of the Earth: A Video Recap 7 WwiiOjyfvAU

NOTE to clarify the often incorrect description of mantle: The mantle contains magma in it’s upper region that seeps into the crust and erupts as lava. The mantle itself is a PLASTIC SOLID that behaves as a viscous liquid over geologic time. Therefore, it is the solid mantle that circulates in convection cells, not the magma.

Scale of The Earth’s Layers

Let’s look at the Earths layers…in sing song! *  *Feel free to sing along. This will not adversely affect your grade

Seismic Evidence of Earth’s Layers  Earthquake- energy released by brittle substance (lithosphere);Energy is in the form of waves that radiate  Seismographs & Seismograms  Surface- cause damage at the surface  Body- travel through the Earth  P- Primary; Arrive 1 st ; Compressional (Longitudinal in physics)  S- Secondary; Arrive 2 nd ; Shearing (Transverse in physics)  All waves increase in velocity with increasing density; but s waves can’t penetrate liquids or gasses  Gap between p & s waves tell you how far away the EQ is 12

13 Seismograms generated by seismographs

Evidence for Earth’s internal structure Seen in seismic wave refraction (change in velocity) when traveling from one density layer into a different density layer Seismic waves through undifferentiated planet Seismic waves through differentiated Earth. Animation of seismic waves through undifferentiated and differentiated Earth:

Self-Check: Do you KNOW the Earth’s Interior? You should know the following and be able to give examples where applicable: 1. How did the Earth form? 2. Why did elements become unevenly distributed throughout Earth’s layers? 3. Name & describe the three compositional layers of the Earth % of the Earth’s crust by mass is made up of what 8 elements? 5. How do oceanic and continental crust differ (aside from one being under water)? 6. What are the boundaries that separate the compositional layers and where are they found? 7. Name & describe the five physical layers of the Earth. 8. Explain why the outer core is liquid yet the inner core is solid. 9. Explain “frictional coupling” and identify where it occurs. 10. What data provides the evidence for the Earth’s interior? Explain.