  We consider a dynamical membrane world in a space-time with scalar bulk
matter described by domain walls. Using the solutions to Einstein field
equations and Israel conditions we investigate the possibility of having
shortcuts for gravitons leaving the wall and returning subsequently. As it
turns out, they usually appear under mild conditions.
  In the comparison with photons following a geodesic inside the brane, we
verify that shortcuts exist. For some Universes they are small, but there are
cases where shortcuts are effective. In these cases we expect them to play a
significant role in the solution of the horizon problem.
