The hypothesis is formulated that our universe and the parallel ‘‘shadow’’ one, as predicted by superstring theory, are connected by a ring of global gravitational instantons. This amounts to a favored conceptual model in which the universe would have split into two equal parts around the Planck scale. In the present formulation, the ten-dimensional space-time in which superstring theory is defined is inflated in two symmetrical directions, reaching a maximal full-fledged representation of E′8 ⊗ E8. The radius of the inflationary universe is determined and arguments are made that strongly restrict the number of interactions between our universe and the parallel one. This yields an explanation as to why the other entity is shadow to ours.