The conundrum posed by Einstein's Theory of Relativity that allows space-time to loop back on itself, theoretically allowing time-travel to the past, has been resolved, according to two physicists writing in the journal New Scientist.
Quantum Theory, which describes small particles as both waves and matter, yields probabilities on the location of these particles, the particles appearing -- in layman's terms -- where the waves interfere with each other constructively.
Daniel Greenberger, from the City University of New York, and Karl Svozil, of the Vienna University of Technology in Austria, solved the relativistic equations for waves travelling backwards in time and found they always interfered destructively.
This means the particles do not appear and the conundrum does not arise.
"If you travel into the past quantum mechanically, you would only see those alternatives consistent with the world you left behind you," Greenberger said, implying that the person concerned would be unable to change the past -- the essential requirement for time-travel to make any sense.
Quantum Theory explains the behavior of sub-atomic particles, which are seen as multiple waves, each following its own path through space-time.
There is nothing in the theory against time travel, as waves travel backwards as well as forwards. Greenberger and Svozil's solutions suggest that when they travelled backwards, destructive interference occurred that prevented anything different happening to what actually occurred.



