  Using the AdS/CFT correspondence in the supergravity approximation, we
compute the energy density radiated by a heavy quark undergoing some arbitrary
motion in the vacuum of the strongly coupled N=4 supersymmetric Yang-Mills
theory. We find that this energy is fully generated via backreaction from the
near-boundary endpoint of the dual string attached to the heavy quark. Because
of that, the energy distribution shows the same space-time localization as the
classical radiation that would be produced by the heavy quark at weak coupling.
We believe that this and some other unnatural features of our result (like its
anisotropy and the presence of regions with negative energy density) are
artifacts of the supergravity approximation, which will be corrected after
including string fluctuations. For the case where the quark trajectory is
bounded, we also compute the radiated power, by integrating the energy density
over the surface of a sphere at infinity. For sufficiently large times, we find
agreement with a previous calculation by Mikhailov [hep-th/0305196].
