As with any topic of interest, there is terminology specific to time travel. This section addresses the vocabulary associated with time travel.
Please note that these pages are under continual development!
Frame dragging refers to the distortion of space-time around a rotating massive body. Increasing mass and increasing rotational rates increase the frame dragging effect.
Speed of light
The speed of light through a vacuum is 299,792,458 m/s (reference). That’s…-fast-!
Whilst it is true that this is the speed of light, it is also the speed limit of the known physical universe; nothing can ever exceed this speed. This is because as objects approach the speed of light, their mass approaches to infinity thus requiring an infinite input of energy…which is not possible. Particles such as photons are able to travel at the speed of light as they have no rest mass.
Even information, such as disturbances in the fabric of space like gravity, can’t travel faster than the speed of light. Consider this. Say the sun instantaneously vanished (let’s say it got a temperature of below absolute zero and took negative space 😉 Question is…what would happen to the Earth? Perhaps you would expect that the Earth would immediately fly away, free from the gravitational pull of the sun. But in reality, the information that the sun has ceased to exist won’t reach the Earth for some 8 minutes, so counter intuitively, the Earth would remain in its orbit around a non existent sun!
Nothing can go faster than the speed of light.
It is true that at one time, there were problems with exceeding the speed of sound and overcoming the issues associated with the onset of the shock wave. Propelling objects – including people – at velocities well beyond the speed of sound is now routine â€“ is it not acceptable to believe that one day we can overcome the obstacles preventing us from breaking the light barrier too?
Current thinking in modern day physics says not. But the interesting question is…
what happens if we could?
A tipler cylinder is a cylinder made of dense material and infinite in longitudinal length. By spinning at high angular velocity about its long axis, local space-time warps due to frame dragging effects and the local light cones become tilted. This means that a cunning navigation around the cylinder makes it possible to cross the â€œworld lineâ€ and enter the â€œspace likeâ€ region of the light cone whilst remaining below the speed of light, i.e. you can go back in time at sub light speed.