Originally Posted by Daniel
If we could see people/aliens/things that have traveled back in time would we not be seeing them now? This kind of suggests that we will never harness the ability to travel back in time.
It is possible to travel into the future though. If you went on a train at near the speed of light and stepped off at the end of your journey you would find that time appears to have jumped forwards for everyone else compared to what you experienced. This is due to time dilation from special relativity.
this is where both theories can answer it, on fate the person was always meant to be at that point in time when they are so no one notices the difference, then you have the multiple universes where if someone on our time line travels back in time and changes something they cause the time line to split off and as far as we are aware everything happened the way it was meant to, until you can track every person on earth at the same time you will never know if people pop in and out or not.
@spats science has been wrong many many times as for the whole energy can't be created, technically everything is a form of energy and before the big bang there was nothing not even time, so in a split second a massive amount of energy came into being that was never there before, now you can assume this is where anti matter comes in as it is the opposite of matter meaning the universe created it self by also creating a negative version of it's self, now the entire fact that there could be a negative version of the universe we can't see says that physics could be very different, extreme gravity has already shown it can effect physics as we know it, so to believe what we know as physics now is the limits of what is possible is basically the same as admitting to believing in creation theory.