geology :: essays research papers

The energy released from earthquakes and forces that move crustal plates are derived from the internal heat engine. Liquid water can exist on earth because the orbit is at the proper distance from the sun. The ozone layer is important to life on earth because it shields living things from uv rays. Constant change and state of flux on earth is caused by slow moving convection currents in the mantle. The internal heat of earth is a result of heat from radioactive decay of certain elements. The main cause of over-use of minerals is expanding populations. Earth is able to hold life because it has sufficient mass to generate gravity to hold gases. The winds, ocean currents and hydrologic cycle from solar energy and the external heat engine. Greatest loss of life comes from landslides and mud flows. Theory of plate tectonics is a revolution because it shows the planet undergoing constant change. Crust, upper mantle, asthenosphere, mantle, outer core, inner core. Geology and human understanding -concept of the vastness of geologic time. Two heat engines of earth- one internal and one external. Scientific method of solving problems starts with data gathering and arrives with a theory. The most abundant gas in the original nebula was most likely the lightest known element. The first internal structure of the inner planets consisted of homogeneous mix of rocks, minerals, elements.  Ã‚  Ã‚  Ã‚  Ã‚   Concept of a large exploding star or nova near the solar nebula is based on evidence that our sun is not large enough to generate the heavy metals in the inner planets. The evidence of life on this planet occurs in some of the oldest rocks found on earth. The source of water on earth is from comet debris. Compaction by the weight overlying layers is least likely to have led to differentiation. Evidence from the Iron Catastrophe is based on the discovery of the layered structure of Earths interior.  Ã‚  Ã‚  Ã‚  Ã‚   Difference between earth and other earth like planets is distance from the sun and related temp differences.  Ã‚  Ã‚  Ã‚  Ã‚   Importance of Oparin-Miller experiments is that they produced organic compounds from inorganic materials. â€Å"Banded iron formations† because they evidence that oceans, marine algae, and oxygen production were present 3 billion years ago. Movement of hot material toward the cool surface is not responsible for modification of earths weather. Most of the mass of earth is mantle. The carbonaceous meteorite that fell in Australia in 1969 was momentous because contained amino acids and other organic compounds. The age of earth-4.6 billion, is determined by analyzing meteorites and moon rocks. The best evidence about the layered structure of earths interior is from reflected and refracted seismic waves.