The radiation zone in general relativity

The radiation zone in electrodynamics is the region far enough away from the charges that the $1\mathrm{/}r$ part of the field dominates over the $1\mathrm{/}{r}^2$ piece. This concept is key in explaining two puzzling aspects of general relativity: The first is an old paradox that invokes the equivalence principle to argue that a static charge in a gravitational field will radiate. The second is the fact that while there are astrophysical sources of gravitational radiation, we do not have any man-made sources.