# Linear frame dragging ?

1. Nov 24, 2008

### tiny-tim

"Linear frame dragging"?

wikipedia at http://en.wikipedia.org/wiki/Frame_Dragging#Frame_dragging_effects says:
(Naty1 has drawn attention to this to this in a Library comment.)

What is this referring to?

Is it a generally accepted terminology, or is it just wikipedia's wishful thinking?

2. Nov 25, 2008

### Jonathan Scott

Re: "Linear frame dragging"?

Linear frame-dragging is the effect that if a test mass is near to an accelerating massive object, its frame of reference is slightly accelerated in the same direction, giving the impression that the rest of the universe is accelerating slightly in the opposite direction. This is consistent with the Mach's principle idea that if the whole universe were accelerating uniformly in the same direction, local reference frames would also accelerate with it, making the acceleration unobservable.

This linear frame-dragging effect is of course tiny in comparison with the ordinary gravitational acceleration and is even more difficult to measure than rotational frame-dragging.

I don't know where the terminology came from; I've heard it before, but I've also heard this effect being referred to as "inertia induction" (by Dennis Sciama, in his fascinating paper "On the Origin of Inertia").

3. Nov 25, 2008

### Naty1

Re: "Linear frame dragging"?

If anyone knows a physical explanation for frame dragging, I'd sure be interested. Wiki derives the ffect from the Kerr metric: does the interaction arise from a specific piece of the Einstein stress energy tensor??

Also, how is frame dragging related to the geodetic effect; Wikipedia has a cross reference with frame dragging, but the relationship isn't clear..

http://en.wikipedia.org/wiki/Geodetic_effect

4. Nov 25, 2008

### Naty1

Re: "Linear frame dragging"?

When I read a few pages about rotational frame dragging in Fabric of The Cosmos by Brian Greene, I see I wrote myself a note:

"seems to follow the equivalence principle of acceleration and "g", but here via
v = w(r)" ....not too far fetched...

Brian Greene says :