A closed, expanding universe in string theory

We present a conformal field theory - obtained from a gauged WZW model - that describes a closed, inhomogeneous expanding and recollapsing universe in 3 + 1 dimensions. A possible violation of cosmic censorship is avoided because the universe recollapses just when a naked singularity was about to form. The model has been chosen to have c = 4 (or c ̂ = 4 in the supersymmetric case), just like four dimensional Minkowski space.