Cosmic topology studies the global shape and connectivity of the universe beyond local curvature.
If certain aspects of cosmic topology were true, the idea that a starship could travel hundreds of thousands of light‑years without ever returning to the same region of spacetime could become problematic.
In a universe with non‑trivial topology, travel paths might close or repeat in unexpected ways, making navigation and fuel planning considerably more complex.
Current observations, especially from the cosmic microwave background and large‑scale structure, tightly constrain possible topologies, yet the question remains unresolved and continues to be investigated.