Paper detail

Nature of the vorticity in the Gödel spacetime

The physical meaning of the vorticity of the matter content in Gödel spacetime is analyzed in some detail. As we shall see, unlike the situation in general stationnary axially symmetric spacetimes (Lewis--Papapetrou), the vorticity in Gödel spacetime is not associated to a circular flow of superenergy on the plane orthogonal to the vorticity vector. This fact might be at the origin of the strange behaviour of gyroscopes in such spacetime. The analysis emerging from the tilted version of Gödel spacetime supports further this point of view. In order to tell apart the two situations (with and without circular flow of superenergy) we introduce two different definitions of vorticity, related to the presence (absence) of such a flow.