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.


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    Title :

    Periodic mass extinctions: Difficulty with astronomical explanations


    Contributors:

    Published in:

    Publication date :

    1989-01-01


    Size :

    7 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




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