Newtonian mechanics assumes that changes in gravitational fields are felt instanteously from any distance...yet Einstein seemed to have toyed with the idea that gravity was a 'wave' in some form or other. If indeed a wave, wouldn't gravity therefore not be instantaneous when observed from long distances? Does anyone know the answer to this question and why?

Thanks

Einstein says changes t the gravitational field propagate at the speed of light.

Radio astronomer Ed Fomalont and theoretical physicist Sergei Kopeikin just recently tested the speed of gravity when Jupiter almost passed a distant quasar...

NewScientist.com may have more info...