The ability to travel back in time by travelling faster than the speed of light, c, was dismissed by Einstein in the parent article, as the new time coordinate, t’, is not negative but imaginary, or t/(square-root)(1- v^2/c^2), where v=velocity, yielding the denominator of a square root of a negative number.
Imaginary numbers are not really imaginary, they are just an artifact of the limitation of taking the square root of a negative number, which is “assumed” to have to be the same number with the same sign (+ or -) to be multiplied by itself to create a square, which is always positive. For the example: (+3) x (-3) = -9, if the +3 and -3 come from different “dimensions”, where square roots of negative numbers like -9 are re-defined to have two solutions equal and opposite (the very premises of what makes physics, math, and the laws of the universe easy to understand, action-reaction, matter-anti-matter, everything is that way), adding a dimension to a line of numbers from negative infinity to positive infinity can better illustrate the purpose. Numbers mean nothing without a visual representation, like when they are plotted on a graph.
Polynomials called complex conjugates have a real part and and an imaginary part (square root of negative 1) and the imaginary parts are opposite in sign. For example, 3 + 4i and 3 – 4i are the complex conjugates of each other, which can be represented in two dimensions, x and y, or x + iy and x – iy. To represent them on a graph, you need to add a new dimension, or z, where x and y are plotted in two dimensions as vectors, and there are two vectors with the same direction only transposed equal and opposite of each other, the same angle with respect to the x-axis but opposite.
Lorentz time dilation is represented with the following equation:
So if velocity is equal to c, it travels into the future at an infinite rate. Other Lorentz transforms suggest it will be infinitely massive if it has mass (photons, or light, have no rest mass), and have “contraction” or zero length in the direction of travel. If it can exceed c (v > c) the denominator has the square root of a negative number, so v, which is a vector expressed in three dimensions, and time is the forth dimension, requires a fifth dimension, zz, with an imaginary part “below” and unseen t for time-axis, which can be represented as rows and columns of different 3-D graphs:
There is the implication of what I say, as a spin on John Titor, that c as the limitation of speed in the universe is patently absurd Some say it means you might go forward or backward in time, but imaginary numbers are only imaginary to the “old” universe the time traveler came from but not where it enters, as there is no communication between the two. Some might say the traveler that exceeds c becomes cloned and one goes back in time, the other forward, the grounds for matter and anti-matter applies to beings, spaceships, etc., as well. To resolve the grandfather paradox, where you cannot go back in time and kill your grandfather, making your original existence impossible, which can only be resolved through a fifth dimension or parallel universe, where information, people, etc., that goes back in time changes the outcome of what was the universe you came from. For every instance of negative time travel, one new instance for every “negative time trip” creates a new universe. You cannot return to the old universe, maybe one slightly different, only further back in time to correct the “wrongs” of the first negative trip, and try to have no impact on the factors you want to affect for the best.