  Relativistic tidal equations are formulated with respect to the rest frame of
a central gravitational source and their solutions are studied. The existence
of certain relativistic critical tidal currents are thereby elucidated.
Specifically, observers that are spatially at rest in the exterior Kerr
spacetime are considered in detail; in effect, these fiducial observers define
the rest frame of the Kerr source. The general tidal equations for the free
motion of test particles are worked out with respect to the Kerr background.
The analytic solutions of these equations are investigated and the existence of
a tidal acceleration mechanism is emphasized.
