Wormholes and Interstellar Travel: An Application of General Relativity
Wormholes and Interstellar Travel: An Application of General Relativity
In Einstein’s theory of general relativity, time and space are made dynamic and are curved by matter and energy. This has allowed physicists to dream up configurations that would allow travel to far distant places in the universe that were once made unattainable by the sheer distances and the natural speed limit of the universe; the speed of light. The theory has also opened up the possibility to travel through time. Like the previous theories of classical Newtonian physics and special relativity which feature flat spacetime, an observer will always measure time going forward; their clock will never tick backwards. However with general relativity, their lies a possibility that spacetime may be warped in such a configuration that you could fly off in a spaceship and come back to earth before you left in a so called “closed time like curve”.
Science fiction has often used black holes has a means of rapid interstellar travel much to the annoyance of physicists. Morris and Thorne (1998)1 have several major objections. The horizon of a black hole is the surface that separates the inescapable interior region with the exterior universe that we live in. At this horizon, the tidal gravitational forces are so large that unless the black hole is larger than 104 solar masses giving it a horizon with a circumference of larger than 105 km if someone were to fall into the black hole they would be ripped apart by their head and feet accelerating at different speeds. The other problem is that the horizon is one way; things can fall in but nothing can ever emerge. Even if a traveller did use a black hole as a one way transport system they could not emerge from another black hole. They would have to emerge from something like a white hole that possessed a “past event horizon” or “antihorizon”. However such an antihorizon has been shown to be highly unstable against small perturbations.
If a wave packet of
In Einstein’s theory of general relativity, time and space are made dynamic and are curved by matter and energy. This has allowed physicists to dream up configurations that would allow travel to far distant places in the universe that were once made unattainable by the sheer distances and the natural speed limit of the universe; the speed of light. The theory has also opened up the possibility to travel through time. Like the previous theories of classical Newtonian physics and special relativity which feature flat spacetime, an observer will always measure time going forward; their clock will never tick backwards. However with general relativity, their lies a possibility that spacetime may be warped in such a configuration that you could fly off in a spaceship and come back to earth before you left in a so called “closed time like curve”.
Science fiction has often used black holes has a means of rapid interstellar travel much to the annoyance of physicists. Morris and Thorne (1998)1 have several major objections. The horizon of a black hole is the surface that separates the inescapable interior region with the exterior universe that we live in. At this horizon, the tidal gravitational forces are so large that unless the black hole is larger than 104 solar masses giving it a horizon with a circumference of larger than 105 km if someone were to fall into the black hole they would be ripped apart by their head and feet accelerating at different speeds. The other problem is that the horizon is one way; things can fall in but nothing can ever emerge. Even if a traveller did use a black hole as a one way transport system they could not emerge from another black hole. They would have to emerge from something like a white hole that possessed a “past event horizon” or “antihorizon”. However such an antihorizon has been shown to be highly unstable against small perturbations.
If a wave packet of
References: 1. Michael S. Morris and Kip S. Thorne-Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity 2. Paul J. Nahin–Time Machines pg500-502 3. J. Richard Gott–The Physical Possibilities of travel through time in Einstein’s Universe pg134-136 4. Stephen Hawking–The Universe in a nutshell pg135-139