Physicists believe the universe is flat, and evidence from leftover light from the Big Bang and the expansion rate of the universe at different locations points to this. David Spergel, a theoretical astrophysicist and professor emeritus of astrophysical sciences at Princeton University, has researched the shape of the universe for decades. In a 2003 study published in The Astrophysical Journal, Spergel measured the irregularity of the cosmic microwave background (CMB), the light left over from the Big Bang.
“A flat universe corresponds to a universe without energy,” Spergel said.
The new research, published in the journal Physical Review D, found that the universe, within a margin of accuracy of 0.2 percent, was flat. The data indicates that the spatial curvature corresponds to zero, meaning that the universe is within a statistical uncertainty – infinite.