Bill Wallace wrote:
>
> What can you tell us of the Kerr solution?
>
> What happens if a gravitating object rotates is the so-called drag effect.
> This is easiest to explain using a spherical body (e.g. a star). When the
> star is nonrotating, a test mass (a small body) which is shot into the
> direction of the centre of mass of the star will stay on a straight
> trajectory (on a `radius'). With a rotating star, this is not the case any
> more. The rotation somehow manages to `drag along' spacetime around it so
> that the test mass would deviate slightly from the straight line path and
> take a course into the direction of the rotation.
>
> As you might know, gravity obeys Einstein's Field equations, and every
> solution of those equations might potentially be realized in the `real
> world'. The solution of the field equations for a spherical, rotating body
> is known as the `Kerr solution', and it predicts the mentioned drag effect.
> I'm not sure whether the solution for a torus is known (at least I wasn't
> able to find anything in that direction), but I'm quite sure that the drag
> effect will take place anyway. After all one can show that any mass
> distribution of finite extension will more or less look like a point mass
> (or a sphere) the farther away you are, but the information about angular
> momentum must not be lost.
>
> http://madsci.wustl.edu/posts/907332964.Ph.r.html
-- It is my opinion that we are being manipulated into a belief system which is reaching a critical point. Someone wants us to think a certain way, and things are being set up so we will follow that perception. It does not follow that the perception reflects the truth. It does not follow that the perception reflects the truth.-- Richard Hoagland
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