Carlip Is Wrong About the Speed of Gravity. Gravity Is a Nonlocal orInstantaneous Phenomenon

Does Gravity Travel at the Speed of Light
http://math.ucr.edu/home/baez/physic...rav_speed.html

Carlip Is Wrong About Relative Motion and the Speed of Gravity

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In general relativity, on the other hand, gravity propagates at the speed of light; that is, the motion of a massive object creates a distortion in the curvature of spacetime that moves outward at light speed. This might seem to contradict the Solar System observations described above, but remember that general relativity is conceptually very different from newtonian gravity, so a direct comparison is not so simple. Strictly speaking, gravity is not a "force" in general relativity, and a description in terms of speed and direction can be tricky. For weak fields, though, one can describe the theory in a sort of newtonian language. In that case, one finds that the "force" in GR is not quite central—it does not point directly towards the source of the gravitational field—and that it depends on velocity as well as position. The net result is that the effect of propagation delay is almost exactly cancelled, and general relativity very nearly reproduces the newtonian result.
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Carlip's key argument here is in the last two sentences in the above paragraph. It has to do with velocity and position. He is arguing that, by some unexplained magic, information about the velocity and position of a massive body, such as the sun or a planet is transmitted to other bodies. This way a receiving body can, by some other unexplained magic, extrapolate the actual position of the emitting body and react accordingly.

The problem is that GR only allows relative position and motion. A body cannot transmit information about its position and motion because it has no way of knowing what they are according to the theory. Since absolute motion and position are forbidden, the body would have to know its instantaneous velocity relative to every other body in the universe. This would require instant communication between it and the other bodies. This, too, is forbidden by the theory.

Carlip is stuck between a rock and a hard place.