blue shift A general displacement of spectral lines to shorter wavelengths that happens when a source of electromagnetic radiation moves toward the observer (see Doppler effect): the greater the velocity of approach along the line of sight, the greater the blueshift. Individual stars within the Milky Way Galaxy frequently show blueshifts. However, with the exception of a few galaxies within the Local Group, including the Andromeda Galaxy, most extragalactic objects exhibit redshifts, due to the overall expansion of the universe. Related category • SPECTRA AND SPECTROSCOPY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |