Absorption lines due to interstellar gas
A)are wider than the lines from stars because the gas is hotter than most stars.
B)are narrower than the lines from stars because the gas has a lower pressure than stars.
C)indicate that the interstellar medium contains dust.
D)indicate that the interstellar medium is expanding away from the Sun.
E)None of the other choices are correct.

Question

Quizplus · Accepted Answer

The absorption lines due to interstellar gas are narrower than the lines from stars because the gas has a lower pressure than stars. This causes the atoms in the gas to have less thermal motion, resulting in narrower spectral lines.

Absorption Lines Due to Interstellar Gas