  It is shown that an Einstein cluster of WIMPs, WIMPs on stable circular
geodesic orbits generating the static spherically symmetric gravitational field
of a galactic halo, can exactly reproduce the rotation curve of any galaxy
simply by adjusting the local angular momentum distribution and consequent
number distribution of the WIMPs. No new physics is involved (assuming the
forthcoming discovery of WIMPs). Further, stability of the orbits can require
an inner truncation of the halo and an explicit example of this is given. There
is no exact Newtonian counterpart to the model presented since pure Newtonian
gravity fails to account for the contribution made by the angular momentum
distribution of the particles in creating the gravitational field. In effect, a
galactic halo is supported by the hoop stresses created by the orbiting WIMPs.
