where do we start? create the universe form the earth and elements
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Where do we start? Create the Universe Form the Earth and elements move the elements into their correct positions build the atmosphere and oceans. The Universe was created 15 billion years ago in one BIG BANG ...... How do we know? Start with the atom. The BIG BANG. ENERGY. Nucleus. }. - PowerPoint PPT PresentationTRANSCRIPT
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Where do we start?
–Create the Universe
–Form the Earth and elements
–move the elements into their correct positions
–build the atmosphere and oceans
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The BIG BANG
• The Universe was created 15 billion years ago in one BIG BANG ...... How do we know?
• Start with the atom
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ENERGY
Nucleus
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ENERGY
Nucleus
} E = hv
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Elemental Absorption
• Every element has a characteristic absorption spectra - (ICP)
Wavelength400 nm 700 nm
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http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014334A.gif
Spectrum of the Sun
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• From the magnitude of the shift we can calculate the speed of the star.
• The more distant stars are moving the fastest.
• From distance and velocity information -> TIME 15 billion years!
Wavelength
400 nm
700 nm
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At the Start
Big Blob of Neutrons (N)
Protons and
electrons
BANG
12 Minutes
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Now we are COOKING ........... Fusion produces heat
E = mc2
1 gram of hydrogen will produce 6.3x1011 j of heat.
Enough heat to boil 2 million liters of H2O
Compare this to our terrestrial energy consumption.
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C
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Elements H-1 through Fe-56
Supernovae
Explosion
Second Generation Star
H through Fe and n
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Elements H-1 through Fe-56
Supernovae
Explosion
Second Generation Star
H through Fe and n
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5
6
7
8
6 7 8 9
Pro
ton
Nu
mb
er
Neutron Number
14C
14Ne-
Beta Decay
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17
18
19
20
20 21 22 23
Pro
ton
Nu
mb
er
Neutron Number
40K
40Ar
e-
Electron Capture
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143
144
145
146
147
89 90 91 92 93
Pro
ton
Nu
mb
er
Neutron Number
234Th
238U
4He
Alpha Decay
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Review of Element Formation
• Big Bang
• Nuclear “Cooking” - Fusion
• Neutron Capture
• What is the end result?
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What about the Earth?
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Another look at the earth on a linear scale.
• Where did all the other elements go? H, He, C, N??
They got BLOWN AWAY
This leaves just Si, Mg, Fe, and O
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.....and just for fun
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Formation of the Earth• The earth started as a hot molten blob of metal and
oxygen
• As the blob cooled, density differences of the original components drove an elemental segregation.
• Metallic iron - The Earth’s core
• Mg, Fe, and Si oxides - The crust
• How do we know?
• We know from earthquake seismology
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A Slice of the Earth
Inner Core
Outer Core
Mantle
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A Slice of the Earth
Inner Core
Outer Core
Mantle
2900 km
• earthquakes travel as shear waves or compressional waves
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• shear waves only pass through SOLIDS (mantle)
• So we have a “liquid” iron core. This has important implications for other elements– Ni, S, Au, Pt, Ag, Pb dissolve in the liquid iron
• What is left is Mg, Si oxide mantle.
• The mantle is not really solid, but really a “putty” that is kept warm by the radioactive decay of 40K, 235U, 238U, and 232Th.
• The heating of the mantle drives convection cells.
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Inner Core
Outer Core
Lower Mantle
Crust
• The mantle melt cycle (subduction/formation) enriches the crust further in Si, Na, K, Ca, and Al
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What about the Oceans and the Atmosphere?
• The Earth is about 0.5% water. Where did it come from?
• The source of water in the early Earth is poorly understood ...we are lucky that it arrived.
• The gravitational attraction of the Earth retained almost all of the water.
• Surface water puts important constraints on global temperature! 0 <--> 100 oC.
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Controls on CO2
• CO2 is controlled by a global scale feedback loop with a time scale of >10,000 years
• Consider the following reactions:
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Controls on CO2
• CO2 is controlled by a global scale feedback loop with a time scale of >10,000 years
• Consider the following reactions:
Generic Weathering Reaction
Generic Precipitation Reactions
Generic Mantle Reactions
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AtmosphereAtmosphere
ContinentalContinentalCrustCrust
OceanicOceanicCrustCrust
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Lets work with units
CO2 (g) 0.0365 %, This is a mixing ratio
O2 20.95%
N2 78.08%
Ar 0.93%
PV= nRT, average mass gas 28.96 g/mol
%, 00/0, ppm, ppb
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Pressure
Atmospheric Pressure is a force: kg/m2
P0 = Mass(atm g)/4(r2
r = 6.37x106 m P0 = 101325 Pa
Ph = Po e -Mgh/RT
M = 0.029 kg/mol
R = 8.314 J/mol K
g = 9.81 m/s2
Scale height 5-6 km
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Unit Conversion