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

Question

Quizplus · Accepted Answer

When galaxies move toward an observer, the wavelengths of the electromagnetic radiation they emit are compressed, leading to a shift toward the blue end of the spectrum, known as a blue shift.

The Doppler Shift for Electromagnetic Radiation from Distant Galaxies Moving