Kevin Street, on Jan. 18 2003,10:32, said:
Well, I think the idea is that a change in that curvature can only propagate at c.
As for how the solar system holds together -- you're right, many of the objections to lightspeed gravity are based on the premise that it would cause a planet to be drawn to where the sun was several minutes in the past rather than where it is now, which would create instabilities that would fly the system apart. But the response is that there's an effect which causes the pull on a moving body to be skewed sideways by just the right amount to cancel out that effect and make it behave as though it is being drawn toward the instantaneous position of the sun rather than its past position. Sounds contrived, I know, but it has been demonstrated to exist in electromagnetic fields, and the math is basically the same with gravity fields.