  Mass currents in astrophysics generate gravitomagnetic fields of enormous
complexity. Gravitomagnetic helicity, in direct analogy with magnetic helicity,
is a measure of entwining of the gravitomagnetic field lines. We discuss
gravitomagnetic helicity within the gravitoelectromagnetic (GEM) framework of
linearized general relativity. Furthermore, we employ the spacetime curvature
approach to GEM in order to determine the gravitomagnetic helicity for static
observers in Kerr spacetime.
