The Rules of Time Travel


Why Parallel Universes May, In Fact, Exist

Because everyone listens to me, and I have so much power, I’ve been working on The Rules of Time Travel. Time travel may indeed be a “thing”. Albert Einstein made us all realize that was possible when he described time as a destination, inseparable from space, spacetime. So the question then becomes, what is possible if time travel is possible? If spacetime is indivisible, then it becomes obvious that there are certain “rules” that would apply to time travel.

Rule #1: You can’t rewrite history. Every point in spacetime exists only once, so if you manage to time travel to a particular point in spacetime, your journey there is irrevocably a data point there, you can’t change it, your journey there has always been a part of that point in space time, and always will be.

So that was as far as I got, there must be other rules. Can you meet yourself and have a conversation with yourself? If you do, will the universe implode? What if you met yourself and killed yourself, would the future you instantly vanish? And suddenly everything becomes more complex.

There is a tantalizing clue in quantum physics, the probability wave. The movements of subatomic particles governed by quantum physics are random, and all the probabilities for a quantum particle exist, until an observation is made which collapses the probability wave. That all by itself seems to open the door to the possibility that an infinite number of copies of every universe exist.

So back to the time travel thing. Maybe my “Rule #1” is nonsense? What if you can go back in time and change history? The implication of that is also that parallel universes do exist and the universe is constantly, and infinitely dividing. What happened in the universe still exists, but when you rewrite history you create a parallel universe that includes the changes you made.

Something to think about as you slurp your morning coffee, or tea, or beer, as the case may be…

4 thoughts on “The Rules of Time Travel

  1. Rule 0: Paradox is an impossible state in a bounded universe with a beginning and an end in 4 dimensions.

    Rule 1: see above, with caveat: you can break a timeline. Your present ceases to exist, and your timeline ends in your past

    Rule 2: any time travel is a one way journey–forward or back. Your present from a past you enter ceases to exist the moment you exist in a past in which you didn’t exist in your present (Past presence negates your present). Simplest example: if you create or bring the ability to return to the present with you, said ability exists in the past and therefore your future state has changed, as said ability did not exist in your past (i.e., your time line no longer exists to return to). Future, ditto: you travel to a future, and return to your present, your knowledge of said future changes your timeline, and now the future you visited no longer exists on your timeline, therefore you could not have visited it (Future presence negates present).

    Rule 3: the purpose of time travel back in time IS to break the timeline. The purpose of time travel forward is to explore, the effects of others changes on the present, and thus, time war.

    Rule 4: the further in either direction you intend to travel, the greater the energy required, going back 100 years? think of the energy required to travel 100 light years in physical distance– assume that’s the energy required + the energy required to break the continuity of time in the first place. Going back to watch the battle of Thermopylae might just require harnessing a the singularity at the centre of a medium sized galaxy.

    And that’s as far as I’ve gotten. I’m still divided on time travel creating parallel universes, or causing an existing timeline to cease to exist, but leaning towards ceasing to exist–time does not “branch off” it changes paths?



  2. Playing around with time travel was one of those things in the Star Trek franchise that always annoyed me.  It seemed like a plot device that was used to “fix” impossible situations quickly and easily with no muss or fuss—a cop out.

    But the more we learn the more it seems likely that time travel may in fact be possible, and in some very minute ways we are already doing it—no pun intended.  Astronauts on the space station are younger by milliseconds than they would have been if they had spent that “time” on the planet.

    Yes there are estimates that the energy involved in time travel would be stellar or galactic in nature.  But if it is possible, in an infinite multiverse, it is happening.

  3. best time travel movie I’ve seen that addressed paradox was based on a Heinlein short story, and it’s not a “fix everything” by time travel plot (I too have trouble with those–they task my ability to suspend disbelief)

    Movie called Predestination based on “All You Zombies.” I can’t explain any of why it was the most brilliant handling of time travel I’ve ever seen without giving away the amazing plot twists, but sufficed to say it is Heinlein…


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