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The Science Fiction of Time Travel

 


Science fiction that veers into the realm of the impossible, is really not science fiction anymore but should probably be categorized as fantasy. For example: time travel. Travelling forward in time is certainly not impossible; we do it every day. Even jumping forward in time is not impossible. Einstein’s rules say that if you can go fast enough, you will move through time faster then a person you left behind. You are not really moving faster in time. The rate of time for you stays the same. But you are moving faster relative to the person who is not moving

Actually no one is ever not moving. If you are on the Earth, the Earth is rotating. It is also going around the sun, which is moving through the galaxy etc. How fast are we moving? Well that is all relative to the observer, who is also going to be moving. The universe itself is expanding so there is no place you can be that is a fixed point that is not moving. When we talk about speed, we are usually talking about a speed relative to a fixed point on the ground. If we say a rocket is travelling at half the speed of light (.5 C), we mean that it is going that speed relative to our observation point on Earth. There is no such thing as absolute speed. There is nothing to measure it against. There is only relative speed. So, if a space ship is travelling at an appreciable fraction of the speed of light (and there is nothing in physics that says we can’t do this) then when he returns to Earth, years, or hundreds of years, or thousands of years will have passed . . . on Earth, depending on how fast he was going and how long at that speed. He would have appeared to time travelled into the future on Earth.

Time travel into the future is very possible (in a relative sense), but it is a one-way trip. Once you go on your fast ship and zoom into the future, you can never go back to the time you started from. You couldn’t tell anyone what the future was like. You would be stuck there. But couldn’t scientists someday find a way to time travel into the past? Nope. No way. It makes no logical sense. For one thing, as stated above, nothing is ever stationary. So, if you were to materialize ten years in the past, you would be materializing in outer space. The Earth would have moved thousands of miles in those ten years. Another problem is that anything you do in the past changes everything that comes after it. Ray Bradbury wrote a story called “A Sound of Thunder” that illustrates the problem nicely. In his story, time travelers go back to the age of the dinosaurs. There is an elevated path for the time travelers to walk on so they don’t change anything in the timeline. But one of them falls off the path and crushes a butterfly under his shoe. When they return to the present (2055) the world is different. (People erroneously cite this story as the source of the term “the butterfly effect” But actually that term was coined in reference to the chaotic nature of weather, where a climate scientist noted that the formation and route of a tornado could have been influenced by a distant butterfly beating its wings weeks earlier. But it is a similar analogy. Whether we are talking about time or climate, in both cases a tiny cause can magnify to a massive effect. Chaos theory rules time as well as weather).

If even this classic science fiction story shows the illogic of time travel, why do writers keep writing stories about it? Well it is of course because there are great story ideas to be had in the world of time travel. Even though it may look like I am complaining about time travel stories, I am not. As a reader I am perfectly willing to suspend my disbelief in the illogic of time travel, as long as the author doesn’t strain my belief in other ways. I was told years ago when I started writing speculative fiction that you are allowed one wonder in your story, just one. Any more than that and you lose credibility with your audience. Most time travel stories I have read at least have their characters strive to impact the timeline as little as possible. Some stories even have Time itself (or maybe the laws of time?) push back against anyone who tries to make critical changes to the past. And there are always rules and conditions that have to be followed when time travelling.

A well told story that doesn’t stretch the suspension of disbelief to the breaking point is what speculative fiction is all about. Whether it is fantasy, or science fiction doesn’t matter as long as the reader can buy into it. And if the author has done his/her homework, it can be educational too. What historical figure would you like to meet in a story?

(My science fiction novel Star Liner, is now available in paperback or as an e-book through Amazon and other online sources).

Link to Star Liner

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