  The geometry around a rotating massive body, which carries charge and
electrical currents, could be described by its multipole moments (mass moments,
mass-current moments, electric moments, and magnetic moments). When a small
body is orbiting this massive body, it will move on geodesics, at least for a
time interval that is short with respect to the characteristic time of the
binary due to gravitational radiation. By monitoring the waves emitted by the
small body we are actually tracing the geometry of the central object, and
hence, in principle, we can infer all its multipole moments. This paper is a
generalization of previous similar results by Ryan. The fact that the
electromagnetic moments of spacetime can be measured demonstrates that one can
obtain information about the electromagnetic field purely from gravitational
wave analysis. Additionally, these measurements could be used as a test of the
no-hair theorem for black holes.
