Time must be exactly one dimensional, otherwise we would find past, present and future twisted around like a complicated Gordian knot with 'loops' that violate the universally observed rule that you can never revisit your past.
Strange things DO happen to time in the quantum world, however.
Mathematically, an anti-matter version of an electron traveling from time T1 to a future time T2 is exactly equivalent to a real matter electron traveling BACK IN TIME from T2 to T1. It is not, however, possible to use this mirror symmetry to transmit information from a future moment T2 to a past moment T1. Also, because of Heisenberg's Uncertainty Principle, electrons can actually travel back in time for short periods of time because we are prohibited from making a detailed measurement of their energy at a specific instant in time. Still, he did imagine some of the problems associated with multi-dimensional time and it is an amusing little book to read if you like that sort of speculation. Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer .