G. W. Swenson, Jr.

Peer Reviewed

Abstract: Radio astronomy is the study of the universe by reception of natural electromagnetic waves in the wavelength range from, say, 1 km to 1 mm. This comprises six decades of the electromagnetic Spectrum, as compared with the less-than-one decade available to earth-based optical telescopes. It is to be expected, therefore, that an enormous amount of information is available about the universe in the radio part of the spectrum. Radio astronomy has been associated with or directly responsible for most of the exciting new discoveries involved in the dramatic expansion in astronomical knowledge of the past twenty-five years. The discovery of the incredibly regular radio signals from pulsars has triggered an intensive investigation into the physics of highly condensed matter: neutron stars. The ability to detect the spectral-line emissions of neutral hydrogen through optically-opaque clouds of dust has permitted new understanding of the structure of our Galaxy, and oft galaxies in general. Radio interferometers with baselines of continental or intercontinental length can now determine the sizes of distant cosmic objects as small as 10-4 seconds of arc, and promise in the immediate future to permit intercontinental distance measurement with precisions of centimeters. The identification by their radio spectra of 33 different molecules in the interstellar gas has produced an upsurge of interest in the physics and chemistry of the interstellar medium and in the process of star formation from interstellar dust and gas. The discovery of the enigmatic quasars, radiiting stupendous amounts of energy from extremely small regions, hints at the existence of fundamental principles of physiti presently unknown to us. In addition to these basic new discoveries, radio astronomy has produced important extensions to our knowledge of many more-familiar astronomical subjects.
Published in: NAVIGATION, Journal of the Institute of Navigation, Volume 22, Number 4
Pages: 324 - 333
Cite this article: Swenson, G. W., Jr.,, "RADIO ASTRONOMY AND THE FREQUENCY PROTECTION PROBLEM", NAVIGATION, Journal of The Institute of Navigation, Vol. 22, No. 4, Winter 1975-1976, pp. 324-333.
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