A wormhole is a hypothetical structure in spacetime that could connect two separate regions of the Universe. Instead of travelling through the ordinary space between two locations, a wormhole would represent a shortcut through the geometry of spacetime. Wormholes arise as possible mathematical solutions to Einstein's equations of general relativity.
In 1935, Albert Einstein and Nathan Rosen described a mathematical structure now known as an Einstein–Rosen bridge. It is often associated with the idea of a wormhole connecting different regions of spacetime. However, the original Einstein–Rosen bridge is not considered traversable.
No traversable wormhole has ever been observed. Some theoretical models suggest that a wormhole would collapse too quickly to allow anything to pass through it. Keeping a wormhole open may require exotic forms of matter or energy with properties that have not been shown to exist on the required scale.
Wormholes are sometimes confused with black holes because both appear in solutions of general relativity. A black hole is supported by strong observational evidence. A traversable wormhole, however, remains hypothetical and has never been detected.