Daily Archives: January 26, 2011

Science Fiction Problems: Time Travel Part III (or, Deadly Deja vu)

This is the third of two parts (lol) on the topic of time travel. To see part I, click here– to see part II, click here.

Well, here we are on the third installment of what was originally going to be a single, quick, cursory look at the infamous Science Fiction staple, Time Travel. Obviously I’m still only scratching the surface with even these three parts, but I think we’re getting a decent grounding anyway.

In this post:

  • Time paradoxes are anomalies encountered when traveling back in time, where an alternate timeline is created to account for the changed events which were the causes for future events
  • An N-Jump is the scenario in which a travelergoes back in time to an identical alternate timeline, and then continues on that timeline with the new series of events
  • An X-Loop or Bow-tie Loop is the scenario in which the traveler goes back in time to an alternate history and convinces his young self not to travel back in time, switching the timeline back to the original, which results in a repeat of his original travel back in time. He then repeats the same actions, creating an unconscious, infinite loop.
  • A Sawtooth Snap is a scenario in which the traveler goes back in time, teaches his young self whom then goes back in time and does the same, perpetuating a constant progression of knowledge and alternate timelines.

I’ve already covered black holes, worm holes, cosmic strings, and time dilation- for this episode of Science Fiction Problems, I’ll be addressing those pesky little time-traveling complications known as Time Paradoxes. While researching a way to explain these, I discovered this site, which also takes a look at how many popular science fiction movies handle them as well. I’ll be using some of M.J. Young’s terminology and using his site as a basis for organization- hopefully not running into a Part IV (sigh).

back-to-the-future marty mcfly
Marty McFly ensures his own existence in an N-Jump alteration of time, jumping ahead to his new future


The Problem of Paradoxes, and Alternate Timelines

While we don’t exactly have a way of testing current theories, we can guess from current physics that time is a pretty linear, bull-headed thing. What happens, then, when you get people pulling it every which way and jumping to a new point in time? Well, if he’s jumping to the future, no big deal. A person taking themselves out of time and dropping back in later affects time no more than if he had taken a long nap. If he goes back in time, especially to a time before he

terminator2-blu-ray Arnold Schwarzenegger motorcycle
The Terminator (Arnold), on the other hand, just keeps getting sent back and stays until he gets killed off by something. Bummer for him, I guess.

was even born, however, then we get what are called Temporal Anomalies, also known as Time Paradoxes. Chances are you’ve heard the term “time paradox” before, and gathered from the dramatic music that those are a bad thing. They are a twist in the fabric in time, creating alternate histories that may essentially erase the original events, or else they may create loops that trap the traveler in an infinite repetition of the same events without even knowing it. These anomalies can be divided by the types of time “jump” that create them, into three groups: N-Jumps, X-loops, and Sawtooth Snaps.

time travel anomalies N-jump

N-Jumps (Successful-ish?)

This type of paradox caused by an N-Jump, called this because of the shape it makes in this diagram. It’s often used as a way to right some kind of wrong in time, like a loved one’s murder, and involves the intrepid traveler going back in time intending to change the events that resulted in the death. The problem is you can’t change the past to change the future without destroying that timeline altogether- when the traveler jumps back in time to a point A, he is actually jumping to an identical copy C, creating an entirely new timeline. The new events, however changed, now “record over” the old timeline, and he continues on within it with all the new changes. If he chooses to cross back to his own time, since he is in the new history, his “future” is now changed based on the differences from the old history. If this arrangement goes wrong, however, you could end up with our next anomaly.

time travel anomalies bow-tie X loopX-Loops (or Bow-tie-Loops if you must)

If the N-Jump anomaly is a “successful” scenario, the X-loop is definitely a failed one. This anomaly occurs  when a traveler tries to undo the event that caused his time-traveling to begin with- and accidentally  creates a time loop that he cannot escape from as time switches between two alternate histories. For  example, lets say that as the traveler in the N-Jump example lives on in the C-D alternate timeline, he  decides he’s made a mistake and that he needs to restore the original timeline. He goes and finds himself as  a young boy and somehow convinces him to never go into the field of science. As the young traveler  matures, he studies art history instead and never winds up building a time machine, and thus never makes  the jump back in time. This essentially erases the alternate timeline C-D, since its cause is now gone, and  switches time back to the A-B timeline. The problem is that we already know what happens in the A-B  timeline- the traveler has lived all his life loving science and eventually builds the time machine. Because time has switched back to this A-B series of events, the cause of the jump is restored and so the C-D timeline is restored as well. This results in a continuous loop, forming the X or bow-tie shape seen to the left, and traps the unfortunate time-traveler forever. Worse (or perhaps better), he would not even be aware of the loop- unless the process happened slightly differently, as in the next example.

time travel anomalies saw-tooth snapSawtooth Snap (A better kind of loop?)

This one’s a tad trickier, but it’s a pretty interesting one. In this scenario, the  Traveler is perfectly happy to stay in the past, and even takes up a job working  as a science teacher in his home town growing up. Unknown to him, one of his  students is actually his younger self, and he teaches a him a great deal about  time travel through the the course of their relationship. As the young traveler  grows up, he is accelerated along the path the old traveler once went down  himself, and builds a time machine with a relative better understanding of how it  should work. The result is that he goes back in time just as before, but is a  different person from before. To break it down, as the diagram to the left shows,  the original timeline is A-B. He first goes back in time, creating timeline B-C, imparting his knowledge on his younger self, who goes back in time to timeline D-E, and so on, through potentially unlimited repetitions. Each time, the Traveler goes back with more knowledge than previously. Alternately, he could purposely “raise himself”, teaching himself everything he knows every repetition, and then purposely going back each time to build on what he’s learned.

These are all some very interesting scenarios that have already been used in many movies and novels, and I hope that my explanation has been a help in your understanding them, and how to use them. I know I’ve certainly learned a lot from my research, and will probably write my own time traveling story to see what new twist I can come up with, and I hope you’ll do the same! Stay tuned for a new segment next week in Science Fiction Problems!

Oh! I almost forgot, here’s Wednesday’s Crazy Prayer Request for the Lantern Hollow Press contest:

*My little baby boy had a terrible accident and his legs are injured and so are his sister’s. Also something bit me and there are four huge demon snakes but I don’t know where they are parked.*