Absorption lines due to the interstellar medium indicate that some components of the interstellar medium are cold and of a very low density.How do they show this?
A)The lines are blue shifted.
B)The lines are red shifted.
C)The lines are extremely broad.
D)The lines are extremely narrow.

Question

Quizplus · Accepted Answer

A cold and low-density medium causes atoms to absorb light at very specific wavelengths, resulting in extremely narrow absorption lines that can be detected and measured.

Absorption Lines Due to the Interstellar Medium Indicate That Some