The apparent motion of objects at speeds greater than that of light ("superluminal motion") is caused by:
A)objects moving almost directly toward us at speeds close to (but less than) that of light.
B)gravitational lensing.
C)objects moving almost directly toward us at speeds greater than that of light.
D)the expansion of space, carrying distant galaxies away from us at apparent speeds greater than that of light.

Question

Quizplus · Accepted Answer

According to Einstein's theory of relativity, nothing can move faster than the speed of light in a vacuum. Therefore, superluminal motion cannot be actual motion, but rather an observational effect. The apparent motion is caused by objects moving almost directly toward us at speeds close to (but less than) that of light. This causes the light emitted by the object to be focused in a cone-shaped region in front of the object, which makes it appear as if the object is moving faster than the speed of light. This effect is known as relativistic beaming, and it is observed in a variety of astrophysical objects, such as quasars and active galactic nuclei.

The Apparent Motion of Objects at Speeds Greater Than That