Abstract Although it is almost certain that comets are shaken free from the Oort cloud by encounters with stars and molecular clouds we have found no process involving these or other perturbers which would give rise to a 30-My periodicity in their arrival at earth.
Periodic mass extinctions: Difficulty with astronomical explanations
Advances in Space Research ; 9 , 6 ; 211-217
1989-01-01
7 pages
Article (Journal)
Electronic Resource
English
Mass extinctions and impact cratering
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