I don't understand how it is possible for an object to be measured as moving through space at FTL speeds. The classic example I've seen is an observer on a rapidly spinning top. The stars will appear to be moving at speeds exceeding light.
This raises all kinds of questions to me:
Doesn't this violate the rules of SR? Does the constant-speed-of-light principle not apply to accelerating objects, but only to uniform motion? Wouldn't other consequences of SR prevent this measurement, e.g., foreshortening in the direction of motion and increase of the mass of the moving object to infinity as it reached or exceeded the speed of light?
If GR does permit these speeds in certain cases, are there any potential applications for communicating information? (I can't think of any.)