Redshift
Redshift refers to the increase in wavelength of electromagnetic radiation observed from a source moving away from an observer or embedded in an expanding spacetime. It is a key observational concept in astronomy and cosmology.
Redshift is discussed in astrophysics, spectroscopy, and observational astronomy.
Status
Redshift is measured through spectral analysis of astronomical sources and is used to infer motion, distance, and gravitational effects. Its interpretation depends on physical context, including relative motion and spacetime geometry.