This possibility is the focus of most current theoretical research involving wormholes. If the wormhole were not much larger than this, then not only would it be useless for transporting spaceships, but quantum gravity would be needed to describe the hole. Analyses of the behavior of quantized fields in wormhole space-times by L.H. Ford and T.A. Roman, Brett E. Taylor, William A. Hiscock and Paul R. Anderson and others have shown that it is unlikely that quantum field effects could hold open a macroscopic wormhole. While at present it appears unlikely that nature allows the existence of macroscopic wormholes, there is still sufficient uncertainty in the arguments to allow theoretical physicists to continue studying this odd and intriguing aspect of space-time. Nobody has yet seen a wormhole, nor are we certain that they exist, but they seem to show up so easily when we do calculations that many physicists suspect that they might actually be out there in the real universe.
Lorentzian wormholes are essentially short-cuts through space and time.
Deep Space 9 . The good news about Lorentzian wormholes is that, after about ten years of hard work, we cannot prove that they do not exist. If Lorentzian wormholes do exist, then it seems classically to be relatively easy to turn them into time machines. This embarrassing feature has led Stephen Hawking to promulgate his Chronology Protection Conjecture. According to this conjecture, quantum effects will conspire to effectively prevent time travel even when it looks like classical physics might allow time travel to occur.