  We consider in the Randall-Sundrum scenario the dynamics of a spherically
symmetric 3-brane world when matter fields exist in the bulk. We determine
exact 5-dimensional solutions which localize gravity near the brane and
describe the dynamics of homogeneous polytropic matter on the brane. We show
that these geometries are associated with a well defined conformal class of
bulk matter fields. We analyze the effective polytropic dynamics on the brane
identifying conditions which define it as singular or as globally regular.
