Several questions come up when considering time travel into the past. One of the main issues with time
travel into the past is the risk of creating paradoxical situations. One well known example of this is
the grandfather paradox. Letís say a person creates a time machine and goes back in time to meet their
grandfather before he has had any children and kills him, this is where the paradox begins. Were the
grandfather killed the time traveler would then cease to exist as he would have never been born and thus
he would have never traveled back in time in the first place and of course that means the grandfather would
have never been killed, the loop goes on and on. Because paradoxes like these could come to fruition they
have become yet another reason that time travel into the past are to some considered impossible.