Download Formation of the Universe and Earth`s Interior

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
O2, Si, Al, Ca, Mg, Fe, Na, K
50% O2; 25% Si
Silicates (SiO4)
Moho- Boundary b/w Crust & Mantle

Mantle


Silicates (SiO4)
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
https://www.youtube.com/watch?v=
WwiiOjyfvAU
7
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!*
http://www.youtube.com/watch?v=Q9j1xGaxYzY
*Feel free to sing along. This will not adversely affect your grade 

Interior Earth
(not to scale)
Be able to locate:
inner core
outer core
upper mantle
lower mantle
continental crust
oceanic crust
In what region would you find:
Moho
CMB
lithosphere
asthenosphere
boundaries that separate a change in composition
boundaries that separate a change in physical properties
“plates”
brittle material
highly plastic material
flowing liquid metal
large scale convection (heat transfer)
frictional coupling
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 1st; Compressional (Longitudinal in physics)
 S- Secondary; Arrive 2nd; 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
Seismograms
generated
by seismographs
13
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: http://tinyurl.com/n88r3jx
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.
4.
99% 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.