  We investigate constraints for including bulk and brane matter in the
Randall- Sundrum model. In static configurations with two zero thickness
branes, we find that no realistic brane matter is possible. We also consider
the possibility that the radion has stabilized by dissipating its energy into
the bulk in the form of some unspecified matter, and find the Randall-Sundrum
cosmological solutions in the presence of bulk ideal fluid. We discover that
the metric is necessarily in a static configuration. We also discover that
there is only one allowed equation of state for the bulk fluid, $p=\rho $,
corresponding to the stiff ideal fluid. We find the corresponding brane
cosmologies and compare them with the Friedmann-Robertson-Walker model.
