Quasars, blazars, and double radio sources may well be the same kind of object, their different appearance simply being caused by their:
A)age: BL Lac objects that evolve through a double radio source phase end up as a quasar.
B)orientation: In blazars the jets point toward and away from us, in double radio sources they point sideways, and quasars are in between.
C)position in the universe: Quasars are in our galaxy, double radio sources are associated with other galaxies, and BL Lac objects are within the vast voids of space between galaxies.
D)size: Quasars are star sized, double radio sources are larger, and BL Lac objects are galaxy sized.

Question

Quizplus · Accepted Answer

The different appearances of quasars, blazars, and double radio sources are caused by their orientation. In blazars, the jets are pointed towards and away from us, whereas in double radio sources they point sideways. Quasars are in between. There is no evidence to support options A, C, or D.

Quasars, Blazars, and Double Radio Sources May Well Be the Same