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).
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