Gravity Without Curved Spacetime: A Simple Calculation
  Classical-particle trajectories are calculated for the static Einstein universe without requiring that the 3-space be closed and curved. Freely-moving test particles are found to return to their starting positions because of strong gravitational-field effects. Possible implications for the underlying (quantum) theory of gravity are briefly discussed. 
F. R. Klinkhamer
gr-qc hep-th