Changes

The '''redshift''' of a given object is a measure of the amount that the [[wavelength]] of its emitted or reflected electromagnetic radiation has increased.<ref name=britannica>{{cite web|url=https://www.britannica.com/science/redshift|title=Redshift|accessdate=2019-04-02}}</ref> This increase in wavelength is prevailingly interpreted as due to the relative motion of a source with respect to an [[Scientific observation|observer]]; a [[light]] emitting source moving away from an observer will have its spectrum shifted toward longer (in optical light, redder) wavelengths. In practice this is analogous to the [[Doppler effect|Doppler shifting]] of sound waves emitted from a moving source. Light emitted from a source moving towards an observer will experience a blueshift. In the case of redshift, however, most of the redshift is believed to be due not to the object moving through space, but to the expansion of space itself.

The '''redshift''' of a given object is a measure of the amount that the [[wavelength]] of its emitted or reflected electromagnetic radiation has increased.<ref name=britannica>{{cite web|url=https://www.britannica.com/science/redshift|title=Redshift|accessdate=2019-04-02}}</ref> This increase in wavelength is prevailingly interpreted as due to the relative motion of a source with respect to an [[Scientific observation|observer]]; a [[light]] emitting source moving away from an observer will have its spectrum shifted toward longer (in [[visible light|optical light]], redder) wavelengths. In practice this is analogous to the [[Doppler effect|Doppler shifting]] of sound waves emitted from a moving source. Light emitted from a source moving towards an observer will experience a blueshift. In the case of redshift, however, most of the redshift is believed to be due not to the object moving through space, but to the expansion of space itself.

==Mathematics==

==Mathematics==