We show that inside the circular photon orbit in the Schwarzschild geometry all the dynamical effects of rotation reverse direction. In particular, for particles and test fluids orbiting the centre on circular (in general non-geodesic) orbits the following occur.(i) The centrifugal force reverses its direction. The centrifugal force attracts orbiting particles toward the centre: the faster a particle orbits, the more strongly is it pushed towards the centre. (ii) The Rayleigh stability criterion is reversed. For a stable angular-momentum distribution, the specific angular momentum decreases with increasing distance from the axis of rotation. (iii) The direction of the viscous torque is reversed. For a fluid with constant angular momentum distribution, angular momentum is transported inwards by viscous torque.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 1990