Lecture 10

Lecture 10 - a period of no more than 500 Ma and possibly...

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Lecture 10 Astrobiology A. Bombardment of Earth- heaviest bombardment ended in 3.8-3.9 Ga with the last  sterilizing impact 4.2-3.9 Ga The oldest identified rocks are only slightly older than 3.85 Ga than the  oldest chemical evidence for life The body fossil evidence suggest that early life was possibly widespread  by 3.5 Ga As soon as the conditions allowed, life arose and colonized our planet in 
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Unformatted text preview: a period of no more than 500 Ma, and possibly as little as 100 Ma B. N=1 • We do not yet know of any other place (outside Earth) where life exists or existed in the past C. Galaxies- • Our solar system is one of more than 100-200 billion star system in our Milky Way Galaxy • Our galaxy is one of 100 billion other galaxies in our universe...
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This document was uploaded on 04/25/2008.

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