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No. 101: Sep-Oct 1995

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Ironclad proof of the moon's origin?

Did earth and moon "coaccrete" at the same time? That is, did two clouds of debris simultaneously collect and coalesce into two rough spheres, which then began orbiting about a common center of gravity? Or, perhaps the earth and moon were once a single mass that ultimately fissioned due to the gravitational tugging of a passing massive object. If either of these scenarios were correct, earth and moon would have similar bulk compositions. This, however, does not seem to be the case.

The abundance and distribution of iron on the moon's surface, as measured by the lunar probe Clementine, indicates that the moon is richer than the earth in refractory (high meltingpoint) compounds. The moon, therefore, almost certainly originated elsewhere, contrary to what most astronomers have longbelieved. Given the constraints of celestial mechanics, the most likely hypothesis postulates a colossal impact involving protoearth and the interloping protomoon. After considerable havoc, the two battered spheres settled down into their present configuration. Thus expire the two most popular theories of the moon's origin. (Lucey, Paul G., et al; "Abundance and Distribution of Iron on the Moon," Science, 268:1150, 1995)

From Science Frontiers #101 Sep-Oct 1995. 1995-2000 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