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Time Travel |
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All objects and observers travel through time. However normally we are restricted to travel from the past to the future, as defined by the entropic arrow of time. Sometimes however, it would be useful to travel through time in different ways. Perhaps you know that there is going to be a spectacular event, or some awesome new device in 50 years, but nothing useful until then. Or maybe you just missed out on the part of the millennium by a few months. Well, wouldn’t it be great to move to these points in space-time? Well, to skip forward, the solution is such – accelerate substantially away from your current location, travel at speeds close to light speed, then decelerate again to back where you started. To those where you started, that key 50 years can have passed. To your point of view, depending on the velocities and accelerations involved, maybe only a single year has passed. A little dull perhaps, but with good in flight entertainment could certainly beat hanging around for that party. However, to travel in the opposite direction is of far greater difficulty – the arrow of time creates an asymmetry and control of motion in the axis of time in the reverse direction is not so easily achievable. A structure known as a wormhole in space-time could perhaps link to another entirely different point in space-time, perhaps entirely outside of your existing light cone. [Morris, Michael S. and Thorne, Kip S.. Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity. American Journal of Physics 56, 395-412 (1988).] However entering a wormhole is problematic – the only known wormhole mouths are black holes, exceptionally massive bodies. As gravity can, much like velocity effect the passage of time, the enormous gravitational field involved can slow down an observer approaching the hole to such a degree that they never reach the mouth until after the end of the universe. As
such, we advise that you simply get to any parties you are invited to, rather
than missing out on the best ones. Then just dilate time to minimise the time
in between them. |
