blue shiftA 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 SPECTROSCOPYAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |