The Morris-Thorne wormhole solution shows a tunnel could in principle stay open and traversable, but only if held apart by exotic matter that violates ordinary energy conditions.
throat_stability ~ exotic_energy / (radius^2)
(Morris-Thorne toy relation)
- Throat radius — width of the traversable tunnel's narrowest point.
- Travel speed — how fast the traveler moves through the tunnel.
- Exotic-matter energy input — the (hypothetical) negative-energy density needed to hold the throat open.
- Field particle lifetime — how long visualised field-line particles persist along the tunnel walls.
Traversable wormholes remain purely theoretical because they require exotic matter with negative energy density — nothing like it has ever been observed.