Abstract
All three-manifolds are known to occur as Cauchy surfaces of asymptotically flat vacuum spacetimes and of spacetimes with positive-energy sources. We prove here the conjecture that general relativity does not allow an observer to probe the topology of spacetime: Any topological structure collapses too quickly to allow light to traverse it. More precisely, in a globally hyperbolic, asymptotically flat spacetime satisfying the null energy condition, every causal curve from to is homotopic to a topologically trivial curve from to .
- Received 21 May 1993
DOI:https://doi.org/10.1103/PhysRevLett.71.1486
©1993 American Physical Society