  Recent measurements of the four pulsar timing arrays were interpreted as a
signal of the low frequency stochastic gravitational wave background. We show
that the amplitude and angular correlations of pulsar timing residuals can be
interpreted as a consequence of the vortical geodetic motions of pulsar's
photons within rotating and expanding Universe. The resulting angular
correlation curves are similar to the Hellings-Downs curve and the observed
amplitude allows the estimate of the vorticity of the Universe. Therefore, no
gravitational wave background is necessary to elucidate the pulsar timing data.
