Doppler Shift and Redshift
Astronomers rely heavily on the speed of light to measure the vast distances and motions of distant galaxies through phenomena known as Doppler shift and redshift. As galaxies move away from us, the light they emit stretches, shifting toward the red end of the spectrum—a phenomenon called redshift.
By precisely measuring this shift, scientists determine not only how quickly galaxies recede but also estimate their distance from Earth. This method has revealed an expanding universe, providing vital evidence supporting theories of cosmic evolution and helping astronomers unravel the mysteries of dark energy and the universe’s accelerating expansion.