Et ormehul, rumtidstunnel[1] eller Einstein-Rosen bro er en hypotetisk egenskab af rumtiden. Hermann Weyl opstillede i 1928 en hypotese om et fænomen, som er en slags tunnel, hvor det er muligt at rejse gennem rum og tid.[2][3]John Archibald Wheeler introducerede termen "wormhole" i 1957 om dette fænomen.[4]
Det er dog endnu ikke blevet bekræftet, at sådanne ormehuller eksisterer.[5]
Selvom det skulle vise sig, så er det meget usikkert om disse mystiske størrelser vil kunne bruges til f.eks. rejser til andre stjerner og galakser.[6]
Der findes forskere som mener at de kan laves med tilstrækkelig energi til rådighed.[7]
^Defense Intelligence Reference Document. Acquisition Threat Support: 2 April 2010, Warp Drive, Dark Energy, and the Manipulation of Extra Dimensions Citat: "...In recent years, however physicists have discovered two loopholes to Einstein's ultimate speed limit: the Einstein-Rosen bridge (commonly referred to as "wormhole") and the warp drive. Fundamentally, both ideas involve manipulation of spacetime itself in some exotic way that allows for faster-than-light (FTL) travel...Essentially, the wormhole involves connecting two potentially distant regions of space by a topological shortcut. Theoretically, one would would enter the wormhole and instantaneously be transported to the exit located in a distant region of space. Although no observational evidence of wormholes exists, theoretically they can exist as a valid solution to general relativity...", backup