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Limitations to growth of microorganisms on Uranus, Neptune, and TitanReappraisal of the probabilistic policy toward planetary contamination by terrestrial microorganisms carried aboard space probes is suggested on the grounds that assignment of numerical probabilities to qualitatively unknown phenomena, as expressed in Phillips's (1974) formulation of the probability of contamination, is inappropriate. As an alternative, it is proposed that fundamental knowledge of the interacting nature of life on earth, interrelations between terrestrial organisms, and continuing effects of these organisms on earth's atmosphere and surface should guide the formulation of a sounder scientific quarantine policy. Simple conservative atmospheric models most favorable for life on Uranus and Neptune are examined. It is concluded that terrestrial microorganisms will not grow on either planet due to limitations of liquid water, atmospheric convection to lethal depths, the absence of energy sources and nutrients, the presence of ammonia and hydrogen, insufficient concentrations of biologically necessary ions, and the lack of a surface. The likelihood of terrestrial microorganism growth on Titan is found to be vanishingly small.
Document ID
19770047145
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Margulis, L.
(Boston University Boston, Mass., United States)
Halvorson, H. O.
(Brandeis University Waltham, Mass., United States)
Lewis, J.
(MIT Cambridge, Mass., United States)
Cameron, A. G. W.
(Harvard College Observatory and Smithsonian Astrophysical Observatory Cambridge, Mass., United States)
Date Acquired
August 8, 2013
Publication Date
April 1, 1977
Publication Information
Publication: Icarus
Volume: 30
Subject Category
Space Biology
Accession Number
77A29997
Funding Number(s)
CONTRACT_GRANT: NGR-22-004-025
Distribution Limits
Public
Copyright
Other

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