Galaxy redshifts refer to the phenomenon of the light emitted by galaxies being shifted towards longer wavelengths due to the expansion of the universe. This effect, known as redshift, allows astronomers to determine the distance of galaxies from Earth and to study the large-scale structure of the universe. By measuring the amount of redshift in the light from a galaxy, scientists can calculate its velocity away from us and gain insights into the dynamics and evolution of the universe. Galaxy redshifts are a key tool in modern cosmology and have led to discoveries such as the expansion of the universe and the existence of dark energy.