Some lobes of radio galaxies are in fact moving faster than the speed of light.

Question

Quizplus · Accepted Answer

According to the theory of relativity, nothing can travel faster than the speed of light. Therefore, it is impossible for any part of a radio galaxy to move faster than the speed of light. Any apparent faster-than-light motion is an optical illusion caused by the angle of observation and the Doppler effect. According to Einstein's theory of relativity, nothing can move faster than the speed of light in vacuum. Therefore, it is not possible for any part of a radio galaxy or any other object to move faster than the speed of light. It may appear that some lobes of radio galaxies are moving faster than the speed of light due to a phenomenon called superluminal motion, but this is actually an optical illusion caused by the orientation of the object and the effects of relativistic beaming.

Some Lobes of Radio Galaxies Are in Fact Moving Faster