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No. 16: Summer 1981

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Earth-moon fission: a slight hint

Although the Sm/Nd isotope ratios of the earth and the chondrites (a type of meteorite) seem pretty close in value, the possibility of a slight but significant discrepancy remains. If this small difference is confirmed, it would strongly imply that the earth's Sm/Nd ratio was shifted after the planet's formation. The most reasonable event that could shift this ratio is an long-debated earth-moon fission, wherein the earth's lighter surface material was somehow torn off to form the moon.

(DePaolo, Donald J.; "Nd Isotopic Studies: Some New Perspectives on Earth Structure and Evolution," Eos, 62:139, 1981.)

Comment. The moon's density is markedly less than the earth's, so the idea is not as wild as it seems.

Hypothetical fission of Earth-Moon The hypothetical fission of Earth-Moon could have shifted the Nd isotope ratio in relation to that of the chondrites.

From Science Frontiers #16, Summer 1981. 1981-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987