Red shift
Red shift is a phenomenon in physic and astronomy.
It occurs when electromagnetic radiation, usually in the form of visible light, that is emitted from an object is shifted toward the red end of the spectrum. The wavelength, in a sense, is increased in red shift. The red shift is considered the opposite of the blue shift. Red shift can occur at any wavelength and be called red shift, even if the waves are technically longer than the color red.
An observed red shift within the universe occurs when distant galaxies, quasars, and intergalactic gas clouds increase in proportion to their distance from the earth. The mechanism of the red shift is the Big Bang model of physical cosmology.
Gravitational red shift is observed if the receiver is located at a greater gravitational potential from the source. The cause of the gravitational red shift is the dilation of time that occurs near huge objects, according to general relativity.
See also