  We study the energy loss of a heavy quark propagating through the matter
produced in the collision of two sheets of energy [1]. Even though this matter
is initially far-from-equilibrium we find that, when written in terms of the
energy density, the equilibrium expression for heavy quark energy loss
describes most qualitative features of our results well. At later times, once a
plasma described by viscous hydrodynamics has formed, the equilibrium
expression describes the heavy quark energy loss quantitatively. In addition to
the drag force that makes it lose energy, a quark moving through the
out-of-equilibrium matter feels a force perpendicular to its velocity.
