Most models for the overall shape and geometry of the Universe—including some exotic ones—are compatible with the latest cosmic observations.

Is the Universe simply connected like a sphere or does it contain holes like a doughnut or a more complicated structure? The topology of the Universe—that is, its overall geometry—remains far from settled, according to a collaboration of cosmologists. Despite past claims that observations of the cosmic microwave background (CMB) rule out various topologies, the researchers contend that many of these shapes, including some strange ones, have not been contradicted by the evidence [1].

The overall geometry of the Universe is thought to have been determined by quantum processes that unfolded in the initial moment of the big bang. Identifying the topology of the Universe would provide researchers with an important clue as to the nature of those quantum processes and could help them sift through the many proposed theories of the early Universe.