In this wikipedia article it is described how a beam of light, with its locally constant speed, can travel "faster than light". That is to say it travels a distance, which, from a special relativistic point of view, is surprisingly big.
I wonder if a gravitational wave on such a curved spacetime (of which the wave is actually part of) behaves equally.
Does a gravitational wave also ride on expanding spacetime, just as light does? Do the nonlinearities of gravitation-gravitation interaction influence the propagation of a wave (like e.g. a plasma) such that light and gravity are effectively not equally fast?
If I want to send a fast signal in this expanding universe scenario, in what fashion do I decide to I send it?