If a light source is approaching you at a speed very close to the speed of light, it will appear:
A)redder than it is.
B)bluer than it is.
C)brighter than it is.
D)fainter than it is.
E)lower temperature than it is.

Question

Quizplus · Accepted Answer

This is known as the Doppler effect, and for light, it causes the wavelength to appear shorter (blue-shifted) as the light source approaches the observer and longer (red-shifted) as it moves away. At speeds close to the speed of light, the shift can be significant enough to cause a noticeable change in color.

If a Light Source Is Approaching You at a Speed