An astronomer is observing the radiation from a distant active galaxy and notices that the amplitude of the signal varies in strength regularly over a certain period. The maximum possible size for the source of this radiation can now be calculated from the

Question

Quizplus · Accepted Answer

The maximum possible size of the source can be calculated from the period of the signal variation, not the amplitude. This is because the time it takes for the signal to vary (its period) can be related to the light travel time across the source, giving an upper limit on its size. The amplitude of the signal does not directly inform about the size of the source.

An Astronomer Is Observing the Radiation from a Distant Active