When radiation from an object passes through the interstellar medium,
A) the object appears refracted.
B) the object appears bluer.
C) the object appears bluer and dimmer.
D) the object appears redder and dimmer.
E) the object's apparent velocity changes.

Question

Quizplus · Accepted Answer

As radiation from an object passes through the interstellar medium, dust and gas scatter shorter wavelengths (blue light) more than longer wavelengths (red light), causing the object to appear redder and dimmer. This is known as interstellar reddening.

When Radiation from an Object Passes Through the Interstellar Medium