Interstellar Cloud Material: Contribution to Planetary Atmospheres

See allHide authors and affiliations

Science  11 Aug 1978:
Vol. 201, Issue 4355, pp. 522-525
DOI: 10.1126/science.201.4355.522


A statistical analysis of the properties of dense interstellar clouds indicates that the solar system has encountered at least a dozen clouds of sufficient density to cause planets to accumulate nonnegligible amounts of some isotopes. The effect is most pronounced for neon. This mechanism could be responsible for much of the neon in Earth's atmosphere. For Mars, the predicted amount of neon added by cloud encounters greatly exceeds the present abundance.