On the influence of gravitational radiation on a gyroscope

We calculate the precession of a gyroscope at rest in a Bondi spacetime. It is shown that, far from the source, the leading term in the rate of precession of the gyroscope is simply expressed through the news function of the system, and vanishes if and only if there is no news. Rough estimates are presented, illustrating the order of magnitude of the expected effect for different scenarios. It is also shown from the next order term that non-radiative (but time dependent) spacetimes will produce a gyroscope precession of that order, providing thereby ``observational’’ evidence for the violation of the Huygens’s principle.