Polarization and its message in astronomy

Abstract

The use of polarization data to gain information on astronomical sources is discussed in a general overview, with an emphasis on the author's personal experience. The detection of light polarization by the human eye is considered, and particular attention is given to intrinsic vs propagation-induced polarization, the possible polarization of cosmic rays, the polarization of stellar and galactic radio emission, polarization of planetary emissions, the variation of polarization observed in short-period pulsars, and recent VLA observations of Cas A, Cyg A, and M87.