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PLANET EARTH08/25/2010CHAPTER ONEWHY WE STUDY EARTH-what we need-ability to grow food-surface space and stability-closed cycles-renewable resources-no net buildup of waste-“how to” manual-sustainable development: development that meets the needs of the present without compromising the ability of the future generations to meet their own needs-manage natural disasters-prepare for disasters-repair environmental damage-maintain habitable environment-natural resources-reserves: the raw materials that we have knowledge of and access to-resources: raw materials that we know about, but can’t necessarily get to-potential-hypothetical deposits-use of previous knowledge to predict the location of resources-renewable: produced by processes at a faster rate than the rate of extraction and use-solar-wind-water?-oxygen-nonrenewable: produced by natural processes at a slower rate than the rate of extraction and use -fossil fuels -water?-energy-while energy use has increased, types of energy have changed-primarily wood and coal > natural gas and oil-energy use in developing countries has increased the most over the years08/27/2010-mineral resources-metals found in many common rocks and minerals-ores: deposits with large amounts of metals -Missouri has the most concentrated lead deposit in the world-primarily used in batteries-mining is a dirty process-leaves behind debris and deposits-can be very dangerous-water -1.46 billion cubic kilometers of water on Earth-96% is salt water-3% is trapped in glaciers-1% is liquid freshwater-mostly in groundwater-used for drinking, growing food, power, waste/sewage, etc.-average use of 6000 liters a day per person-250 liters per day per person for domestic use-35% goes to agriculture-53% is for industries-12% is for everything else-soils -soil: organic material and weathered rock-needed for agriculture-nutrient reservoir-needed for clay production-considered a carbon reservoir-great at cleaning water through filtration-easily eroded, contaminated, and renews slowly-natural hazard: events produced by natural processes that have the potential to cause loss of life and change our built environment-hazard: the intensity of a particular event-cannot be prevented-same in all areas despite levels of population-risk: the potential damage caused by an event-can be reduced with better scientific knowledge and better public policy-risk varies based on populations, etc.-hurricanes >typhoon > cyclone-impacts -storm surge-strong winds-the most dangerous-rain -flooding-low pressure causes water to get sucked up into the sky-fueled by warm waters-floods -occur when more water flows into a basin than can flow out-can be good or bad-beneficial-deposits nutrient rich sediments-regulates river-channel development-increases flood plain elevation-detrimental-inundates areas outside of channel -leaches contaminants out of the soul-earthquakes: shaking caused by breaking rock along geological faults -faults can be identified, and potential for destruction can be estimated-can cause landslides, floods, and tidal waves-volcanoes-provide mineral resources-can erupt explosively or with slow, steady, lava flow-landslides: downhill movements of rock, mud, and soil-bolides-extraterrestrial material that falls from space to earth08/30/2010-humans and global change-humans have always impacted their environment-more important now due to size increases and global scales-acid rain-sulfur gases released from coal mining and ore smelting combine with oxygen to make sulfuric acid, which is then rained down-acidifies lakes and bodies of water-impacts biosphere-destroys buildings, statues, etc.-stratospheric ozone-ozone: a reactive oxygen gas-while considered a pollutant in the lower atmosphere, it blocks harmful UV rays in the upper atmosphere-ozone is destroyed by CFCs (Freon, etc.)-phased out by 1996-large ozone hole over Antarctica-global warming-CO2 is a greenhouse gas that traps heat in the Earth’s atmosphere-levels in the atmosphere have increased due to fossil fuel burning, deforestation, etc.-global temperatures have already started to rise09/03/2010CHAPTER 2HOW WE STUDY EARTH-the Earth System-climate-weather: specific conditions (temperature, precipitation, etc.) at a particular location-climate: long term weather cycles averaged over many years (daily cycles, seasons, etc.) -includes interactions among the atmosphere, cryosphere, hydrosphere, and biosphere-hydrosphere and atmosphere are responsible for energy shifts-plate tectonics-lithosphere-the crust plus the upper mantle-asthenosphere-deep mantle-where we actually see convection-explains why we have earth quakes, etc.-driven by internal heat-convection-hot matter from the mantle rises-as it warms, it rises, and as it cools it sinks, warms, and rises again-can pull plates apart-creation of new material-lateral material movement-Geodynamo System-two parts-inner core and outer core-makes a magnetic field around the Earth-magnetic field tends to switch-protects the Earth from some harmful material -suns radiation -movement in outer core stirs up electrical flow in inner core-inner core behaves like a bar magnet-geodynamo system: rapid motion of the liquid outer core stirs up electrical flow in the solid inner core, causing Earth’s magnetic field-deflects solar radiation-geologic time09/08/2010CHAPTER 9HISTORY OF EARTH PARTS 1 AND 3-Big Bang-about 13.7 billion years ago-solar system-about 4.5 billion years ago-origin of the solar system-nebular hypothesis -sun formed from a cloud of gas and dust that contracted-cloud began to contract and rotate-forms a ball that then flattened out into a disk around a central protosun-materials collide and clump together into small chunks or planetesimals-protoplanets-terrestrial planets: planets formed primarily of rock-gas planets: planets made primarily of gases-small bodies of the solar system-asteroids-pieces of planets that never came together -asteroid belt located between Mars and Jupiter-source of meteorites-comets-located farther out-primarily dust and ice-have fairly regular orbits-Early Earth-differentiation: transitioning from uniform planetesimal to a layered planet-how did Earth differentiate?-Earth heated up and melted-impact formation of the moon-an impactor about 1/3 the size of Earth hits Earth-essentially liquefies the surface-Earth reforms into a molten body-debris begins to orbit the Earth-condenses-Earth’s rotation speed is increased, and its axis is tilted by 23H-cause

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