gravity's speed

[dennis grace]

In response to Paolo Cavallo's claim that:

>>Every fundamental interaction in Nature propagates at the speed of 
>>light - not
>>only gravity. It's required by special relativity.

--Matthew Hoyt ruminates:

>Well, only sorta kinda.  During BIG gravitation events this changes. 

<snippage of colorful but none-too-illuminating interchange between Einstein
and Born>

>As one with a BA in physics I translate to mean that big gravitational
>changes propagate slower
>and faster that the speed of light, if for no other reason than that the
>gravitational change is manipulating
>the spacetime the wave would propagate through.  Though in any case the
>overall speed of
>progation is near the speed of light (faster or slower), rather than
>instanteously (whatever that
>could mean in light of special reletivity).

Yeah, but the Special Theory of Relativity has an almost mystical, almost
canny capacity for enforcing that c speed limit.  Without even looking, I'm
guessing this gravity speed propogation thing mimics the action of
microwaves in a waveguide.  Within the waveguide, the wave front travels at
velocities greater than c along a zigzag path, but overall end-to-end speed
in a microwave guide never exceeds c.  In other words, from point of origin
to point of effect, the observed propogation speed of the event never exceeds c.

I've never even traveled faster than sound, but as for Special
Relativity--well, I still think we need a faster universe.

dgg
___________________

Dennis Grace
University of Texas at Austin
English Department
Recovering Medievalist

"Oh God comma I abhor self-consciousness."  --JB