"Henry Spencer" wrote in message
...
In article ,
snipsnap
Finally, a subtle point which some may have missed he what propagates
at the speed of light is *changes* to gravitational fields. The fields
themselves are (loosely speaking) the local curvature of space, and they
don't have to propagate to have effects, any more than a hillside needs to
propagate for a ball to roll down it. There is nothing that constantly
travels back and forth between the Earth and the Sun to keep Earth in its
orbit, so asking how quickly the whatever-it-is travels is meaningless.
--

That's an interesting observation.
But is this not similar to stating that although by definition EM fields
(photons) travel at speed of light, it has not been proven that/if a
continuous electric field has effect at speed of light ?

If this analogy makes sense, then I still think you are out of luck :
Any 'effect' of the electric field (even if it is a charge spinning around
another one) means that there is a change in magnetic field, which means a
change in electric field etc..
And changes travel at speed of light. The change seems continuous, but can
be because the changes are much larger than quantum limits, and because the
two charges dont move near speed of light...

There is no reason to assume that gravitational fields dont work the same
way.

Rob

"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |