Darkphyre's Multiverse

So, you have your time machine and you?ve decided that you should make use of this marvel of fantastic science. You can?t really travel to the future; the present, as we perceive it, doesn?t accept the existence of the future because we hate to think that we have no control over our own destiny.

So, accepting this view, you have chosen to return to the past.

There are a number of problems one could face when going backwards through time. The most prominent of these problems is the Temporal Paradox - the effects of our actions on the previous time frame to which we travel, and how they change our present and future.

The most frequently encountered Paradox is known as the Grandfather Paradox.

For whatever reason you travel back in time, lets say, you arrive at a time when your grandfather is still a child, and has not of yet met your grandmother. Inadvertently, as an effect of your presence, your young grandparent dies - so he never meets your grandmother, they never give birth to your father/mother, and so you are never born either - Leaving the universe with a history in which you no longer exist.

But what now?

Many have theorised that any change in the past will only get to the future (leading to the time you consider the present) with the normal passage of time. That would mean you could continue to exist until such a time that history can no longer explain you. This could be the time your grandfather was supposed to meet your grandmother, the birth of your father/mother, your birth, or the moment you chose to go back in time. Needless to say, at some point you would cease to exist.

Or the past would never catch up with your present because both time periods are moving forward at the same speed so the present keeps moving away from the past. In this case you would always exist regardless of killing your grandparent.

But I believe this view is wrong!

You have travelled to the past, and your grandfather has died. From your perspective, this is still the past, so the future of this point in time has already happened, as have all the moments leading up to your time travel. And therefore, you have already reached all the points when you should cease to exist, and you are no more.

And to maketings more confusing - if you no longer exist, then who killed your grandfather?

The Grandfather Paradox always leads to a causality loop. If you cease to exist with the death of your Grandfather, then you couldn?t have travelled back in time and gotten him killed.

This would cause the history to revert to the original timeline. Meaning that you suddenly exist again and will go back in time and repeat the mistake you made the first time around. And so you cease to exist again.

And this cycle will go on for eternity. That?s if the strain doesn?t rip the space-time continuum apart.

It should be noted that some believe it impossible to change the past. Your travelling to the past results in the death of your grandfather, but now two realities exist: one where your grandfather lives (and so do you) and one where he doesn?t (and neither do you). But this means, when you travel back in time, all you have done is switched to another reality in which you actions made you extinct.