What are the Rules to Time Travel?
Time travel is science fiction's most popular premise. But what are the rules for traveling through time? Home
What happens if you already exist in the time period you travel to?
That's a question that seems to have a million answers from nothing happens there's just two of you to it being a really bad thing for your health.
As a side note in the realm of superheroes, Superman can change time back for the entire planet if he flies around really really fast around the globe. See Superman the Movie, if you doubt me.
In my short story, "The End of Time" the rule was that you would be unable to physically leave the time machine if you were already present in that particular time period.
In the movie Time Cop, if you touched a copy of yourself you would die an agonizing death.
In the Back to the Future trilogy encountering yourself did not cause any problems with the space time continuum or end the universe.
What about that Grandfather Paradox?
The grandfather paradox is a paradox of time travel in which inconsistencies emerge through changing the past. The name comes from the paradox's common description as a person who travels to the past and kills their own grandfather. By killing your grandfather you could cause your father to not be born and thus wipe yourself from existence. If you no longer exist, how could you go back in time to kill your grandfather. I first heard this mind numbing paradox explained on the movie, "The Final Countdown" by actor Martin Sheen. That's got to be one of the best time travel movies of all time.
It begs the question what if you went back in time to fix a problem in your life? If you succeed and you come back to the present all would be presumably alright at that point. But if you wiped said problem from existence, why would you have went back in time to rectify said problem in the first place? Is time big enough to hold more than one timeline, one where your problem existed and one where it did not, and does the timeline where your problem existed before, still exist for another version of yourself?
This is why nobody will ever be able to kill Hitler. If you kill him in the past, then you'll never have a reason to go back in time to kill him in the first place. I'm not sure what happens if you go back in time and just happen to run over Hitler with a car by accident.
Imagine the chaos that would occur if you went back in time five minutes and shot yourself. Talk about infinite loops.
The Terminator taught us that you could indeed send your father back in time to get with your mother and thus well, you know.
Sometimes clothes are optional?
For some strange reason clothing isn't always able to go back in time with the time traveler as in the case of the Terminators and the man in the "Time Traveler's Wife".
What happens when you travel at the speed of light?
According to Einstein if you were able to get into a spaceship and travel at the speed of light a few hours when you came back everyone you knew would be old and grey, but you'd only be a few hours older. The problem would be getting back those years you lost.
What is the difference between a parallel world and an alternate timeline?
In my own opinion an alternate timeline is a detour off of another timeline. It occurs when a time traveler goes back in time and creates a change in history, no matter how small the change. All parallel worlds exist at the beginning of the universe. They themselves could be considered separate timelines or roads. Any offshoot or deviation in their particular time streams would create an alternate timeline in that particular parallel world. So let's say there's a parallel world with green humans and all is going well in their timeline. Now suppose a time traveler goes backward into the world of green human's timeline and screws around. Now you have two separate timelines for the same parallel universe.
In my short story book, "Sci-Fi with a Twist" most of my stories involve time travel or at least some element of time travel.