NATS 1840 Lecture Notes - White Dwarf, Protostar, Hydrosphere
20 Nov 2012
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Document Summary
Science, technology and the environment (sc nats 1840a) . Readings: 4. 4, 4. 5 bulk of test covers biogeochemical cycles chapters 6 and 7, 3. 3-3. 7, 4. 4, 4. 5, 4. 7, same format. All of the energy available on earth comes to us from the sun. Temp: 6000 degrees (surface) 10^7 degrees (core) Sun"s power output varies continuously, but with some regularity. 11-year sunspot cycle correlated with solar output. Brightness (output) on a long term increasing trend; has probably rise by 25% since protostar phase. When supply of hydrogen runs out, sun will die out and become a white dwarf in about 5 billion years. Lithosphere: solid rock crust floating on a liquid interior. Hydrosphere: temperature allows liquid water (71% of surface) Earth intercepts only a fraction of sun"s total power output: an average about 1360 w/m^2 (the solar insolation) at top edge of atmosphere. Most of this energy is delivered in the form of visible light.
