From what I read, long ago, the flaw in time travel is as follows:
You cannot go "back" in time, as to say past the point of when the "time machine" was activated, as the two endpoints of travel are unable to meet, we have already successfully sent protons(or neutrons, electrons, something "tron"-y) back to when the machine was first turned on, which was, at the time, a momentous achievement.
I have no idea of the location of this article but if I come across it again I shall post it here