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No. 12: Fall 1980

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Gravity down, mass up

The variation of the gravitational constant, G, with time would not be considered seriously were it not for the surprising coincidence of two enormous dimensionless numbers:

(1) The ratio of the electrical to gravitational force between the electron and the proton in a hydrogen atom; and (2) The ratio of the age of the universe and the atomic unit of time.

If these two ratios are truly equal, then G must decrease with time.

Beyond the unstable feeling one gets, there is nothing in physics or cosmology to discourage a belief in time-varying gravity. Indeed, some as-tronomical data weakly support the idea. It is geophysics, though, where one finds strong evidence. Measurements of the decreasing length of the day and the expansion of the earth give about the same value for a decreasing G -- after other contributing factors have been eliminated.

An interesting consequence of all this is that astrophysical theory seems to require that a decreasing G be balanced by increasing mass. Experiments are now underway to detect the continual creation of mass in terrestrial objects.

(Wesson, Paul S.; "Does Gravity Change with Time?" Physics Today, 33:32, July 1980.)

Decreasing length of the day over time

From Science Frontiers #12, Fall 1980. 1980-2000 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