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No. 32: Mar-Apr 1984

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Natural Laser Beacons

"It has long been realized that the Earth's upper atmosphere cannot be in thermodynamic equilibrium, and during the last decade astronomers have made telescopic observations of nonequilibrium processes taking place in the upper atmospheres of our Earth-like neighbors, Mars and Venus. A preliminary analysis by Michael Mumma, of Goddard Space Flight Center in Maryland, and his colleagues. indicated that processes analogous to optical pumping in laboratory lasers were taking place and led to the coining of the term 'natural lasers.' Now, Deming and colleagues from the Goddard team have taken new observations of emission from Mars and Venus at wavelengths near 10 micrometers. and modelled them to show that stimulated emission -- the effect which makes lasers so powerful -- accounts for up to seven per cent of the total emission. This is not a large amplification factor by laboratory standards, particularly for a CO2 laser. But, the authors speculate that the sheer size of the natural lasers could make them useful tools in the future for communicating with distant civilizations beyond our own planetary system."

The atmospheres of Mars and Venus are almost pure CO2 . The CO2 molecules are excited by the absorption of energetic solar photons; then, thermally emitted photons at about 10 micrometers from lower reaches of the atmosphere collide with the excited molecules, stimulating them to emit another 10-micrometer photon, thus doubling the number of photons. This is typical laser action. Deming and Mumma speculate that the natural laser action existing in the Martian atmosphere could be intensified and focussed into an intense beam of infrared radiation of enormous power by placing two large mirrors in orbit, creating a space-borne analog of a laboratory laser. With this huge laser, one could conceive of communicating with neighboring stellar systems.

(Taylor, F.W.; "Natural Lasers on Venus and Mars," Nature, 306:640, 1983.)

From Science Frontiers #32, MAR-APR 1984. 1984-2000 William R. Corliss

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  • "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