Upon thinking about this, I realize that the above comment about images from hubble being clear, proves that gravitational waves must be faster than light, as light is faster than sound. If they propagated atc, space would be full of them and these curvatures would cause large distance images to blur, which they do not.
There seems to be alot of confusion about special relativity, as opposed to general relativity. Special relativity is from the point of view of an observer. A spaceship shrinks as it approaches c from an observers point of view, but in reality it stays the same length, ie in its own reference frame. The argument about causality being violated by gravity being faster than light is an observational illusion, just like the spaceship's shrinking.
Quote:Person A sends a FTL signal to person B someplace far away. Upon receiving A's signal, B sends a signal to person C who is next to A. Upon receiving B's signal, person C kills person A.
Wrong: it takes a finite amount of time for signals to travel from A to B and from B to C even at c^c. Any additional observe D that uses special relativity for an observational effect, still cannot send a message back in time, even if they observed events in a backwards order.
Again, the clearity of long distance images proves that gravity propagates much much much faster than c!