Red Shift: Explaining Cosmic Expansion

Redshift is a fundamental phenomenon in physics and astronomy where the light or other electromagnetic radiation from an object is stretched to longer (and therefore redder) wavelengths. This occurs when the source of the light is moving away from the observer, or when space itself expands between the source and the observer. The Three Causes of Redshift

Cosmological Redshift: The universe is expanding. As light from distant galaxies travels across vast stretches of the universe, the expansion of space itself stretches the light waves, shifting them toward the red end of the visible spectrum. The further away the galaxy is, the more its light is redshifted.

Doppler Redshift: Just as the pitch of a police siren drops as it drives away from you, light also experiences a Doppler effect. If a star or galaxy is moving away from Earth, the light waves it emits get elongated, resulting in a shift toward red.

Gravitational Redshift: According to Einstein’s theory of general relativity, light loses energy as it escapes the immense gravitational pull of massive objects like black holes or neutron stars. Losing energy forces its frequency to drop and its wavelength to stretch. Why It Matters Red shift | Astrophysics | Physics | FuseSchool