Some quasars show absorption spectra with a smaller redshift than their emission spectra. This indicates that
A) they are much closer than previously thought.
B) we still don't understand redshifts.
C) there is cooler gas between us and the quasar.
D) their black holes are still contracting.
E) their black holes are still expanding.

Question

Quizplus · Accepted Answer

The presence of absorption spectra with a smaller redshift than the emission spectra of quasars indicates that there is cooler gas between us and the quasar. This gas absorbs some of the light from the quasar, imprinting absorption lines onto the spectrum at a redshift that corresponds to its velocity relative to us, which is typically less than the quasar's own redshift.

Some Quasars Show Absorption Spectra with a Smaller Redshift Than