PLANET EARTH 08 25 2010 CHAPTER ONE WHY 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 manage natural disasters prepare for disasters repair environmental damage maintain habitable environment natural resources sustainable development development that meets the needs of the present without compromising the ability of the future generations to meet their own needs 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 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 potential hypothetical deposits solar wind water oxygen nonrenewable produced by natural processes at a slower rate than the rate of extraction and use fossil fuels water energy 08 27 2010 mineral resources 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 years 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 rain flooding the most dangerous 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 earth 08 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 ozone a reactive oxygen gas while considered a pollutant in the lower atmosphere it blocks harmful UV rays acidifies lakes and bodies of water impacts biosphere destroys buildings statues etc stratospheric ozone 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 rise 09 03 2010 CHAPTER 2 HOW WE STUDY EARTH the Earth System climate location weather specific conditions temperature precipitation etc at a particular 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 time 09 08 2010 CHAPTER 9 HISTORY 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 23 cause of seasons 09 13 2010 CHAPTER 8 CLOCKS IN ROCKS geologists use rocks to reconstruct Earth s history