Term
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Definition
| 4 billion years ago, universe is expandind it is dated by the wilkison microwave anisotropy probe |
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Term
| What are the 2 major eons? |
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Definition
Precambrian : single cell life first 4 billion years
Phanerezoic: Multi cellular |
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Term
| Describ geological dateing |
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Definition
relative the top rocks are newer than the deeper ones relative to eachother
absolute dating measure half life of different elemesnt using the parent element and lead the daughter element to tell time |
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Term
| Describe our solar nebula |
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Definition
interstellar cloud of dust and gas collecting if it is cold it will fuse adn become a star
if it is hot it will go through condesation and turn into solids at high temperatures |
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Term
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Definition
| In front of the frost line heave elememnts condense behind it methane and water condense |
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Term
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Definition
| at first it was the accreation of plnetesimals that had no core.. about 4.45 billion years a go a mars sized planetesmal collided with earth and gave us our iron core |
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Term
| Describe the moon and its creation |
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Definition
it is important for our tilit of 23.5 degrees adn the ocean tides with out stabilizing tilt we would have 2 seasons day and night
moon has few volatile elements but som similar to the earht like its oxygen isotopes which leads to the giant impact theory... when the mars sied planetesmal hit earht it launched silcon rich rocks into orbit where they condensed to form the moon during the end of the bombardment period |
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Term
| Describe the bombardment period |
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Definition
| this was the first 100 million years planetesmals hit earht eventually it was sporatic for the following 600 million years because there were less planetesmals... the friction created from bombardment heated the rocks letting out gasses creating the atmosphere called degassing. large objects could dry up the oceans to the atmosphere |
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Term
| How did we lose hydrogen in the atmosphere? |
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Definition
| water in the atmosphere would be photolyzed or brok into oxygen and hydroxyl the hydrogen is light and escaped the atmposphere creating a dense atmpsphere for earth |
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Term
| How was oxygen added to the atmosphere? |
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Definition
| photolysis of water and c02, oxidation of volcanic gasses such as H2 and C0 created h20 and c02 so oxygen did not build up in the atmosphere |
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Term
| what was the early atmosphere like? |
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Definition
| This is not known because there were no rocks for the atmosphere to settle into like limestone or shale, however we know there was more carbon for sure and this made it warmer than it is now |
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