Dynamics of Extended Objects and a Stationary Axially Symmetric Cosmological Model

We find a new solution describing a homogeneous stationary axially symmetric model, which, in contrast to the Gödel model, does not contain closed timelike lines. We find exact solutions corresponding to the motion of a null string in the rotating Universe and show that these solutions crucially depend on the initial data. To obtain more detailed information on the cosmic string dynamics, we performed numerical simulations indicating essential differences in the behavior of strings and null strings in the presence of global rotation of the Universe. These numerical solutions show that the string manifests involved oscillations, varies its shape with the appearance of loops and cusps, and twists into a spiral.