Red shift is a phenomenon observed in light from distant objects, such as galaxies. When these objects move away from us, the light they emit shifts toward the red end of the spectrum. This shift indicates that the object is receding, which is a key piece of evidence for the expansion of the universe. The concept of red shift is closely related to the Doppler effect, which describes how the frequency of waves changes based on the motion of the source. In astronomy, red shift helps scientists measure the speed at which galaxies, like Andromeda, are moving away from Earth.