Quasar spectra

Astrophysical measurements enable us to probe the variation of the fundamental constants. The energy scale of atomic spectra is given by the atomic unit rneA/h2. In the non-relativistic limit, all atomic spectra are proportional to this constant and analyses of quasar spectra cannot detect any change of the fundamental constants. Indeed, any change in the atomic unit will be absorbed in the determination of the redshift parameter z (1 + z = u/ is the redshifted... 

Radio Astronomy. Most radio astronomy applications operate in the microwave spectrum. Usually, naturally occurring microwave radiation is observed however, radio astronomy has been used to measure distances precisely within the solar system. Radio astronomy has also been employed to map the surface of Venus, which is not visible via optical telescopes because of its dense cloud cover. The technology has expanded astronomical knowledge and has led to the discovery of new objects, including radio galaxies, pulsars, and quasars. Radio astronomy allows objects that are not detectable with an optical telescope to be seen. These objects are some of the most extreme and... 

Fig.6.82. Spectrum of a quasar exhibiting huge Doppler shifts [6.157] (Copyright 1982 by Scientific American, Inc.. All rights reserved)...

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