When astronomers look at stars outside of our galaxy, they have noticed that the color of the stars appears to be shifted slightly to the red end of the visible spectrum; this means that the wavelength of the light coming from those distant stars is longer than expected. If this red shift is assumed to be caused by the relative motion of the stars, what does that tell us about their movement?

They are moving toward the Earth.
They are moving away from the Earth.
They are not moving relative to the Earth.
Both the Earth and the star are stationary.