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No. 63: May-Jun 1989

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The Planets Are Unpredictable

It was only about 40 years ago when astronomers, aghast at Velikovsky's vision of worlds in collision, stated very firmly that the solar system was presently stable and had been so for eons. Now it seems that they may have been a bit hasty and all-encompassing. Not that the Velikovsky scenario is correct or that Mars might at any moment depart from its present orbit, but rather that astronomers must now admit an inability to predict planetary motion over billions of years - even tens of millions of years! For the solar system, if those ubiquitous computers are correct, is not a well-behaved family of planets. J. Laskar concludes from extensive numerical experiments:

"The motion of the Solar System is thus shown to be chaotic, not quasiperiodic. In particular, predictability of the orbits of the inner planets, including the Earth, is lost with a few tens of millions of years."

(Laskar, J.; "A Numerical Experiment on the Chaotic Behavior of the Solar System," Nature, 338:237, 1989.)

Comment. Laskar's comments are directed toward the future, but the same conclusions should apply if we ran the solar system backwards in time. From this very narrow perspective of celestial mechanics, one cannot say positively that the planets, the inner ones especially, could not have radically altered their orbits within the past few millions of years.

Reference. See ABB1 in our catalog: The Sun and Solar System Debris for more on the solar system's instability. This book is described here.

From Science Frontiers #63, MAY-JUN 1989. 1989-2000 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