Here is more info from the University site on this effect:

Astronomers use Doppler shifts to calculate precisely how fast stars and other astronomical objects move toward or away from Earth. For example the spectral lines emitted by hydrogen gas in distant galaxies is often observed to be considerably redshifted. The spectral line emission, normally found at a wavelength of 21 centimeters on Earth, might be observed at 21.1 centimeters instead. This 0.1 centimeter redshift would indicate that the gas is moving away from Earth at over 1,400 kilometers per second (over 880 miles per second).

Shifts in frequency result not only from relative motion. Two other phenomena can substantially the frequency of electromagnetic radiation, as observed. One is associated with very strong gravitational fields and is therefore known as Gravitational Redshift . The other, called the Cosmological Redshift, results not from motion through space, but rather from the expansion of space following the Big Bang, the fireball of creation in which most scientists believe the universe was born.

What is peculiar is these mysteries are not discussed as often as you would think.  Let’s see if you have heard of all of them…what do you think?

We hope you like the video and are inspired to learn more about space!  Check back for updates.

thanks to the University of Illinois for the info