  We show initial data for gravitational axial waves, that are twice
differentiable but which are not $C^{2}$. They generate wave pulses that
interact with matter in the radiation cosmological era. This forces the
radiation matter to rotate. This rotation is permanent - it persists after the
passage of the gravitational pulse. The observed inhomogeneities of the cosmic
microwave background radiation put a bound onto discontinuities of superhorizon
metric perturbations. We explicitly show that a class of smooth initial metrics
that are at least $C^{2}$ gives rise to gravitational wave pulses that do not
interact with the background during the radiation epoch.
