survey of astronomy astro1010-lee.com [email protected] chapter 6 our living earth
TRANSCRIPT
Chapter 6A
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Solar System Formation
Cloud of gas and dust contracts due to gravity. Conservation of Angular Momentum means it spins faster and faster as it contracts
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Chapter 6Our Solar System
Condensation theory:
Interstellar dust grains help cool the cloud, and act as condensation nuclei to produce flakes, grains, lumps, planetesmals then planets
The interior of the Earth has been determined by studying the transmittal and reflection of Seismic Waves within the Earth.
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Chapter 6
Seismic waves are sound waves generated by earthquakes. They are compression waves and sinesoidal waves. They reflect from and transmit through layer interfaces with the Earth.
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Chapter 6
Can use the pattern of reflections made during earthquakes to deduce interior structure of Earth
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Chapter 6
The crust of the Earth is divided into several plates that move with respect to each other. The movement is driven by convection currents in the mantle. Plate movement results in earthquakes and volcanism.
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Chapter 6
Interactions between the plates are: transform, sliding against each other; divergence, separating; convergence, coming together.
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Chapter 6
Ocean Floor Spreading shows evidence of Magnetic Field Reversal
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Chapter 6
When plates slide against each other cracks (faults) occur and earthquakes happen.
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Chapter 6
The twisting Pacific plate has produced many earthquake zones and many active volcanoes.
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Chapter 6
At divergent boundaries new crust is made.
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Chapter 6
At convergent boundaries crust is lost by subduction (sliding under) and crumpling (mountain building)
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Chapter 6
The Earth’s magnetic field appears to be generated by electric currents circulating the liquid iron core.
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Chapter 6
The Magnetic Field deflects the Solar Wind around the Earth much like a stone in a stream deflects water. Charged particles that penetrate the boundary are trapped in the Van Allen Belts
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Chapter 6
The trapped hot charged particles in the Van Allan belts are shunted toward the magnetic poles where they interact with the air molecules. The particles are cooled by the air which glows as auroras.
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Chapter 6
The Earth’s Biosphere, Oceans and Atmosphere, come from hydrogen rich gasses trapped inside the Earth during creation. By far the most abundant of the trapped gasses are methane, ammonia, and water. The Earth is the only planet where conditions are right for liquid water to exist on the surface.
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Chapter 6
Free H
CH4
NH3
OH2
CO2 N2
Water Plant Life
O2
Trapped gasses OutgassingWaterNitrogenCarbon Dioxide
Plant LifeOxygen
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Chapter 6Earth’s Atmosphere
• Troposphere is where convection takes place – responsible for weather
• The blue curve shows the temperature at each altitude
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Chapter 6The Atmosphere
Convection depends on warming of ground by the Sun
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Chapter 6
Ionosphere is ionized by solar radiation, and is good conductor
Reflects radio waves in the AM range, but is transparent to FM and TV
Ozone layer is between ionosphere and mesosphere; absorbs ultraviolet radiation
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Chapter 6
The Human ElementMore Humans,Industrial Revolution
Global Warming (?)
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Chapter 6
