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23 Cards in this Set
- Front
- Back
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Big bang theory occured
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13 billion years ago
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summary of big bang
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All mass clumped into one point when an explosion goes off and dust and gas are everywhere. With conservation of angular mommentum and gravity planetesimals are pieced together. planets expand as they cool.
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movement from homogenous to heterogenous
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All mass in one point --> Nebula --> Galaxy --> solar system --> Planet
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the clumping of dust and gas into a nebula causes what
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thermonuclear reactions (Hydrogen --> helium)
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Our galaxy is made up of more than just hydrogen how did it get here?
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Nuclear synthesis and fusion of hydrogen to higher elements.
Also, Supernova explosions. |
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concentration of such nuclear reactions made up the
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Sun
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Concentration of heavy elements to make protoplanets is a process called what
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Accretion
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Early earth was termed proto earth and it had
-life? - activity? - continents? -oceans? |
No,
volcanic no, no |
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The seperation of objects according to their density.
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Density stratification.
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Why is density stratification discussed here?
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because dense objects sunk to the center of the earth to make its core (Ni and Fe), while the gases spun out to form the atmosphere.
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originally the earth's surface was
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a magma ocean till it solidified into the earth's crust.
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how do we know so much information about the earth's center?
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Seismic activity studies.
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How do seismic activity prove that the earth is layered?
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because there are no straight relationships between a waves start and end.
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Initially the crust was too hot for water. Once it cooled, where did all the water come from (2 theories)
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Condensed out of the sky, clouds.
Delivered by comets. |
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Where did the salts in the ocean come from?
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Dissolving rocks and volcanic emissions.
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Atmospheres went through 3 phases. What were they?
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1.) Nebular atmosphere- gases from nebula. gas escaped because earth was too hot and hot air rises.
2.) volcanic atmosphere- alot of H and carbon dioxide like other terrestrial planets. 3. modern atmosphere came about because of other microbial life. |
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What are the oldest fossils found?
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Believed to be Archea (blue-green algae)
Later first hard fossils found. Stromatolites (in teh Archea family) |
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What are the three branches of life? what are the differences?
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Archea
Bacteria Eukaryotes- organelles and an enclosed nucleus |
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It is believed that life evolved where?
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in the ocean.
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why?
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Similarity of our body fluids, same main elements, water needed for survival, same temp, and pH as our bodies.
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Life is based on organics and up until now there were no organics. How was this mystery solved?
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Miller-Urey experiment: Proved that organic products can be made from inorganic reagents. MADE ORGANIC AMINO ACIDS AND SUGARS from ammonia, methane, water and hydrogen.
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where is it theorized that the first live organisms arrived from? and where did they evolve?
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from space
at hydrothermal vents. |
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How are geological times dated accurately?
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Absolute age dating of Uranium and comparing it to its known 1/2 life.
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