That quasars were at cosmological distances yet appeared like ordinary faint stars meant:
A)they were the brightest stars ever observed.
B)they must be very large.
C)they must contain many O and B type stars.
D)they must be producing such large quantities of energy than even fusion could not explaintheir output.
E)they must be very small, but bright due to gravitational lensing.

Question

Quizplus · Accepted Answer

The fact that quasars appeared like ordinary faint stars despite being at cosmological distances meant that they must be producing a tremendous amount of energy, far beyond what could be explained by fusion processes alone. This led to the hypothesis that they were powered by the accretion of matter onto a supermassive black hole, which releases enormous amounts of energy in the form of radiation and jets of relativistic particles. If quasars were at such great distances yet appeared as faint stars, it meant that they were producing an enormous amount of energy, far beyond what fusion could explain. This led to the understanding that they must be powered by supermassive black holes, which produce radiation as they consume surrounding matter.

That Quasars Were at Cosmological Distances Yet Appeared Like Ordinary