Quote:
Originally Posted by sjastro
The issue is not the speed of gravity itself but whether changes to the field strength itself result in information of the change being transmitted at the speed of light. This information is conveyed in the form of gravitational waves.
According to GR gravitational waves are transmitted at c, by allowing the components of the metric tensor to vary with time. The mechanism is similiar to altering the strength of a magnetic quadrupole which results in electromagnetic radiation travelling at c.
Regards
Steven
|
Yes.
"by allowing the components of the metric tensor to vary with time"...ummm, who's time are we talking about here Steven? A moving frame of reference would not agree with the same account because the very same light source which was used to measure as a comparison is constant in both frames...in ALL frames...or was the field in motion because the origin is actually moving, and the mover is in fact stationary? Light has no reference frame, ergo it lies to us by offering only a constancy. There is no cosmic ether wind, therefore no fixed background structure with which to measure against.
It's fine to talk about gravity when it's this or that, but the moment you want to get specific, ie make a comparison between the speed at which the metric changes versus the speed at which light propagates, you cannot. A fast moving passer-by would see a slow changing metric, true?