Uran & TopoLady
TopoLady
Have you ever thought about whether the universe itself could be a topological manifold—like a 3‑sphere or a torus—so that light takes loops that come back to where it started? It’s almost like carving a marble sculpture that folds back on itself.
Uran
That’s a neat way to picture it. If the cosmos were a closed manifold, photons could in principle trace out loops and return to their origins, like a light‑speed racetrack. Our measurements of the cosmic microwave background and large‑scale structure suggest the universe is almost flat, but a small curvature could still let those loops exist. It’s like a gigantic marble that’s been gently bent so the marble’s surface wraps around itself—only the universe’s “marble” is still being inspected.
TopoLady
It’s pretty neat—like a marble that’s barely been nudged, so the seams are almost invisible. If the curvature is just enough, the photons would dance around the whole thing, looping back like a careful sculpture catching itself.
Uran
Exactly, it’s almost a subtle curvature, like a slightly bent sheet that still looks flat to the eye. The photons would just keep circling until something—gravity, inhomogeneities—breaks the symmetry. The idea is elegant, even if our observations keep nudging us toward a nearly flat universe.