A new study by Stephen Hsu and Roman Buniy of the University of Oregon says the idea of building a traversable wormhole may be fundamentally unstable.

However, they also assert that “semi-classical” wormholes — in which the space-time “tube” shows only weak deviations from the laws of classical physics — are the most desirable type for time travel because they potentially allow travellers to predict where and when they would emerge.