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Impact constraints on the environment for chemical evolution and the continuity of lifeThe moon and the earth were bombarded heavily by planetesimals and asteroids that were capable of interfering with chemical evolution and the origin of life. This paper explores the frequency of giant terrestrial impacts able to stop prebiotic chemistry in the probable regions of chemical evolution. The limited time available between impacts disruptive to prebiotic chemistry at the time of the oldest evidence of life suggests the need for a rapid process for chemical evolution of life. On the other hand, rapid chemical evolution in cloud systems and lakes or other shallow evaporating water bodies would have been possible because reactants could have been concentrated and polymerized rapidly in this environment. Thus life probably could have originated near the surface between frequent surface-sterilizing impacts. There may not have been continuity of life depending on sunlight because there is evidence that life, existing as early as 3.8 Gyr ago, may have been destroyed by giant impacts. The first such organisms on earth were probably not the ancestors of present life.
Document ID
19900061046
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Oberbeck, Verne R.
(NASA Ames Research Center Moffett Field, CA, United States)
Fogleman, Guy
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Publication Information
Publication: Origins of Life and Evolution of the Biosphere
Volume: 20
Issue: 2, 19
ISSN: 0169-6149
Subject Category
Space Biology
Accession Number
90A48101
Distribution Limits
Public
Copyright
Other

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