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keepit
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What is frame dragging?
I don't think this is strictly correct. Frame dragging is a particular feature of General Relativity. It generally isn't talking about particles, but macroscopic objects. It has been tested for the Earth by Gravity Probe B (http://en.m.wikipedia.org/wiki/Gravity_Probe_B).in a nutshell its a theory which states space is elastic and particles have inherent spin that can via its angular momentum influence the space around it by exchanging its angular momentum. Keep in mind its a theory that has yet to be proven. Though the link below shows one test with some results. Those results are not enough to validate the theory
http://simple.wikipedia.org/wiki/Frame-dragging
I don't think this is strictly correct. Frame dragging is a particular feature of General Relativity. It generally isn't talking about particles, but macroscopic objects. It has been tested for the Earth by Gravity Probe B (http://en.m.wikipedia.org/wiki/Gravity_Probe_B).
Interesting, so Einstein's trampoline is true according to the Gravity Probe B data. The massive Earth warped it and the rotation of the Earth drags its fabric. That is how I understood frame dragging at this moment :-)
Consider for example Kerr space-time. The observers who are at rest in the gravitational field (i.e. those who have constant spatial coordinates in the Kerr chart) follow orbits of the time-like killing vector field ##\xi^a = (\partial_t)^a##; these are the static observers. Now even though they are all static, it turns out that their twist 4-vector ##\omega^a = \epsilon^{abcd}\xi_b \nabla_c \xi_d \neq 0##; now ##\omega^a## is nothing more than the curved space-time version of the curl ##\nabla \times \vec{\xi}## from vector calculus so physically what this means is that if a static observer carries with him a set of 3 mutually perpendicular gyroscopes and attaches a displacement vector to an infinitesimally nearby static observer then this displacement vector will rotate relative to the gyroscopes.
But how will an observer sitting at infinity see this? Well to him the observers are all hovering in place (constant spatial coordinates in the Kerr chart) so the displacement vector simply points from one static observer to an infinitesimally nearby static observer and doesn't do anything at all as far as he's concerned, meaning the observer at infinity will see the aforementioned static observer's gyroscopes rotate relative to him i.e. he sees the static observer precess in place. This is an example of frame-dragging.