Inside+Terrestrial+Worlds - ASTR 1010 Astronomy of the...

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Unformatted text preview: ASTR 1010 Astronomy of the Solar System Inside Terrestrial Worlds Study Guide Unit 7 Textbook Ch. 7 Review Question 1.) The fact that the Earth has undergone differentiation suggests that the Earth's interior a) has always been solid. b) must not have a core. c) causes the continents to move. d) was once liquid. Differentiation Early bombardment was so intense that the terrestrial planets were molten throughout. This allowed for differentiation dense material sinks to the core and lighter material floats to the top. When the planet cools, this structure is preserved. Planetary Geology Terrestrial World Layering Study Guide 7.1 Layers of composition Core Nickel/Iron Mantle Rocky material Crust Granite/Basalt Inside Terrestrial Worlds Not in study guide How do we know what's inside a planet? Seismic waves. Inside Terrestrial Worlds Not in study guide Terrestrial World Layering Not in study guide Lithosphere layer of relatively cool and rigid rock that "floats" on the warmer, softer rock beneath. Strength of Rocks Study guide 7.2 Depends on composition, temperature, and surrounding pressure. High temperature - weaker High pressure stronger Traces of water weaker Rocky material can deform and "flow" over geological time-scales. Molten Rock (Liquid) Study guide 7.3 Viscosity describes the "thickness" of a liquid in terms of how rapidly it flows. Low viscosity flows quickly (water) High viscosity flows slowly (molasses) Viscosity is a measure of how much "resistance to flow" a fluid has. Geology Geology is a heat-driven process. As thermal energy escapes from the core into space, the surface of the planet changes. 2.) The Earth's core is hot today due to a) solar heating. b) recent large scale meteoroid bombardment. c) radioactivity. d) heat left over from the Earth's formation. e) both c and d Interior Heating Study guide 7.4 Accretion Process by which objects gather together to make larger objects. Friction from collisions generates thermal energy. Not a very important source heating now. Interior Heating Study guide 7.4 Differentiation All terrestrial planets are differentiated. Friction during separation of lighter and heavier material generates thermal energy. Interior Heating Study guide 7.4 Radioactivity Unstable elements spontaneously decay into different elements, releasing thermal energy in the process. This is now the most important heating source for the Earth's interior! Interior Heating Study guide 7.4 Tidal heating Heat from internal friction produced by tidal forces. Interior Heating Interior Cooling Study guide 7.5 Conduction Thermal energy is transferred by direct collisions between atoms and molecules. Heat flows from hotter objects to colder objects. Most important in the lithosphere, where the distances between different parts of the system are relatively small. Interior Cooling Study guide 7.5 Convection If conduction and radiation can't move heat quickly enough to prevent a density change, the hot material will move. Important in the mantle. Slow in the mantle (thick paste.) Interior Cooling Study guide 7.5 Eruption Volcanic activity in lithosphere. Interior Cooling Study guide 7.5 Thermal radiation (infrared light) from the surface. Interior Cooling 3.) The Earth's surface absorbs energy from sunlight and then radiates about as much energy back into space. The best proof you can offer for this fact is that the average surface temperature on Earth is a) warming slowly (~years.) b) not warming rapidly (~days.) c) half light and half dark. d) warmer at the core than on the surface. Lithosphere Lithosphere gets thicker as the rate of heating drops. Geological activity Lithosphere thickness The moon is geologically dead its all lithosphere with no molten part (no internal heat to move!) 4.) In general, what kind of planet would you expect to have the thickest lithosphere? a)The largest planet b)The smallest planet c)The planet farthest from the Sun. Role of Planetary Size Not in study guide Thinner lithospheres can crack into plates more easily than thicker lithospheres. Role of Planetary Size Not in study guide Why are larger planets geologically active longer? heating _ rate volume R3 lifetime 2 R cooling _ rate surface _ area R Larger radius longer lifetime Smaller radius shorter lifetime Role of Planetary Size ...
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This note was uploaded on 04/18/2008 for the course ASTR 1010 taught by Professor Jones during the Spring '08 term at Georgia Southern University .

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