What observational fact convinces astronomers that the source of energy in a typical quasar is physically very small?
A)the extremely high redshift of its spectrum
B)the appearance of all quasars as starlike objects in our sky
C)the extreme distance of all quasars
D)the rapid variation of the intensity of the source

Question

Quizplus · Accepted Answer

The rapid variation of the intensity of the source is the best observational fact that convinces astronomers that the source of energy in a typical quasar is physically very small. If the energy source were larger, the variation in intensity would be slower because of the larger physical size. Thus, the observed rapid variation implies a small physical size for the energy source.

What Observational Fact Convinces Astronomers That the Source of Energy