The Doppler shift for electromagnetic radiation from distant galaxies moving away from the observer is called a:
A)red shift.
B)blue shift.
C)black shift.
D)vacuum shift.

Question

Quizplus · Accepted Answer

When a distant object is moving away from an observer, the wavelength of its electromagnetic radiation appears longer, and thus, the light shifts towards the red end of the spectrum. This is called the red shift, and it is one of the primary pieces of evidence for the expanding universe.

The Doppler Shift for Electromagnetic Radiation from Distant Galaxies Moving