Hasn't been demonstrated quite yet.
In quantum mechanics, mathematically, a certain amount of energy on the planck length can disrupt space time to where anything that goes through ends up in another place and time.
The issue is, why in the world the machines would do this when we consider the solution to grandfather paradox (alternate timelines/dimensions)?
Anything sent into another time is gone from our continuum, what they do to change that past has no effect on the present.