2/9/10 11:52 AM Early Earth There was very little primordial oxygen about 1 billion years ago 10% or present amount . 600 million years ago sudden increaces Origin Of oxygen Biological activity started 2 billion years ago , plants convert co2 to o2 and trap carbon . Questions If the earth had no water and therefore life had never occurred what would the earth?s atmosphere be like? The atmosphere would have a lot of carbon dioxide in it which would produce a large greenhouse effect , like venus . If you were trying to locate a planet with life on it what atmospheric constitients would you look for ? The Ocean water covers 71% of the surgace area of the earth , wit an average depth of 4 km. Helps regulate and moderate temperature Important for evoution of atmosphere Liquid nessicary for life Origin of oceans Water from condensed steam from volcanoes Water from comets that hit the earth Water removed by subduction Gaia A theory that the earth self regulates , the earth through the life on it helps regulate the atmosphere. The Magnetic Field Solid core rotates fater than surronding liquid core This dynamo acts like a generator The field is roughly aligned with the rotation axis He field flips every 10000 years or so The Moon Exploring the Moon 1609- Galileo observes moon through telescope 1959- Moon orbited by first spacecraft Luna2 a soviet spacecraft July 20, 1969 ? first maned landing , Apollo 11 , neil Armstrong & buzz Aldrin Lecture 13 2/9/10 11:52 AM 2/9/10 11:52 AM
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