### Special relativity extended beyond light speed

University of Adelaide applied mathematicians have extended Einstein's theory of special relativity to work beyond the speed of light - despite the fact that the theory holds this to be impossible.

Published in 1905, the theory explains how motion and speed are always relative to the observer's frame of reference. It connects measurements of the same physical incident viewed from these different points in a way that depends on the relative velocity of the two observers.

"Since the introduction of special relativity there has been much speculation as to whether or not it might be possible to travel faster than the speed of light, noting that there is no substantial evidence to suggest that this is presently feasible with any existing transportation mechanisms," says Professor Jim Hill.

"About this time last year, experiments at CERN, the European centre for particle physics in Switzerland, suggested that perhaps neutrinos could be accelerated just a very small amount faster than the speed of light; at this point we started to think about how to deal with the issues from both a mathematical and physical perspective."

While those results were eventually disproved, the team continued with their work, extending special relativity to a situation where the relative velocity can be infinite, and can be used to describe motion at speeds faster than light.

"Our approach is a natural and logical extension of the Einstein Theory of Special Relativity, and produces anticipated formulae without the need for imaginary numbers or complicated physics," says Hill.

Their paper, here, doesn't explain how faster than light travel could be achieved, but is purely mathematical, centering around the dependence on relative velocity of the Lorentz transformation.

"Should it, however, be proven that motion faster than light is possible, then that would be game changing," says Dr Barry Cox.

"Our paper doesn't try and explain how this could be achieved, just how equations of motion might operate in such regimes."