In what sense are the quasars "quasi-stellar"?
A)Their energy production is hydrogen-helium fusion, like main sequence stars.
B)They are upscale versions of O stars, yet hundreds of times more massive.
C)Their luminosity comes from the millions of supergiants that compose them.
D)Their spectra are like that of ordinary stars.
E)In short time exposures, their images looked stellar.

Question

Quizplus · Accepted Answer

The term "quasi-stellar" refers to the fact that, in early observations, quasars appeared to be point-like sources similar to stars. However, subsequent observations revealed that they are actually extremely distant and luminous objects with properties distinct from those of ordinary stars. None of the other choices accurately describe the nature of quasars. Quasars were originally believed to be stars due to their stellar-like appearance in short time exposures. However, upon closer examination, it was realized that they are actually distant objects with extremely high luminosities, powered by supermassive black holes at their centers. The term "quasi-stellar" refers to this early confusion about their true nature.

In What Sense Are the Quasars "Quasi-Stellar