Science Fiction Problems: Time Travel Part I (slightly more complicated than most people think)
Posted by erikthereddest
After a short break, I’ve decided to try and explain an apparently commonly misunderstood subject in science fiction: time travel!
This is the first part in a series. For part II, click here.
In this post:
- Time is the 4th dimension and is directly related to 3-dimensional space, creating a manifold called space-time
- Black holes distort space-time and theoretically allow for time travel if they don’t crush you with infinite gravitational force
- Worm holes fold space-time, allowing travel between two points in space or time regardless of distance
Carl Sagan has been quoted as saying that time is “resistant to simple definition”, yet science fiction tends to be a little flippant with one of the biggest mind-bogglers in the scientific community. We’ve heard phrases like “space-time continuum” and “4th-dimensional space” thrown around in movies from Back to the Future to the Terminator, but in classic Hollywood tradition, they tend to gloss over the details important to the actual mechanics of time travel… usually so that they can take liberties with the way it actually works based on our current knowledge.
I’ll admit, it is a little…opaque, and we certainly haven’t figured it out yet (and we likely won’t this side of eternity), but it is not impossible to get a general grasp of the prevailing theories. For whatever reason it is very common for main-stream science fiction to make broad assumptions that only results in contradictions and peeved academics. So, here are some of the basics in the clearest terms possible in two parts, for your information and enjoyment:
Time is the 4th Dimension
We are all very familiar with the three dimensions of height, width, and depth as they are what we move around in throughout our daily lives, however, it may surprise you to hear that time itself is a dimension. While objects can move through three dimensional space, they also move through time, being in different positions and different states as time progresses, so that for each specific time there is an associated position in space. This means that position in space is directly related to time, hence the aforementioned and favorite buzzword “space-time”. This is an essential concept to absorb, so please excuse the science-speak if it burned your eyes to read. This is actually where a lot of science fiction goes wrong right off the bat, creating some silly explanation that ignores this relationship. In order to bend time, you need enough energy to bend space- which is estimated, depending on the method, to be upwards of half the mass-energy of an entire galaxy. Yeah. Flux capacitor or no, that DeLorean isn’t going far on garbage-power alone. This means that would-be time travelers need to resort to a few tricks of physics to get anywhere, but luckily our great universe is happy to cooperate, providing several naturally-occurring means (assuming current theories prove to be correct).
Black Holes, Spinny or Otherwise
You’ve probably seen a few movies with black holes in them, but not many films highlight their time-bending properties, usually only providing a hazard for adventuring spaceships or the occasional space station. There are actually two kinds of black holes theorized (as I was honestly surprised to discover), one being the Schwarzschild black hole, which is roughly cone-shaped and simply draws in and crushes all matter with infinite gravity, and the other being the Kerr hole, the spinning swirl that is most often seen in science fiction movies. Black holes are created from the collapse of burnt-out stars, and it is theorized that if certain conditions prevail, the energy that usually creates a Schwarzschild hole spins and creates a Kerr hole instead, eliminating the matter-crushing singularity at the tip of the cone-shape and instead offering a window or portal to other times or parallel universes (if they exist; I’ll talk about them in Part II). In theory (mostly Einstein’s), because space is so distorted at the center of black holes, time itself is distorted, and if we could figure out how, we could enter that point of warped space-time and travel to the past or future. So, that’s the way it supposedly works with the better known method, now here’s the lesser known one.
Worm Holes (No, not like in Star Wars)
Black holes may be a staple of science fiction, but worm holes do not see nearly as much screen time. The idea behind them is that objects of mass in space distort space-time, curving it. Picture a sheet being held taut with a bowling ball set in its center- the fabric bows under the weight and if you were to drop a marble, it would roll toward the bowling ball. This is, incidentally, one of the theories for how gravity works, but that’s a bit of a tangent. If you were to fold the sheet so that there was space between the two halves, and then apply pressure to the same point on both, the two points would meet across the gap, as pictured in the illustration. If space time were folded in such a manner and two corresponding points of pressure applied, it would theoretically create a sort of tunnel between the two, through which it might be possible to travel. It doesn’t matter how long that “sheet” is (how far away those points actually are from one another), if the fabric of space can be folded like this, it is as if there is no distance between them at all. This is great way to shorten distances in space to avoid the necessity for faster than light travel, but it would work similarly for time as well, theoretically allowing for travel between any two points in time.
I hope this hasn’t been all too confusing, but as I see I am running a bit long here, I will pick up this subject next week in Part II, discussing a few other potential means of time travel and also a few of the problems with it that are often ignored.
So, what are some of the badly-done time traveling stories you’ve read? What about stories that handled time travel in a respectably convincing way?
About erikthereddestI'm a Masters student in English, and I love technology and Science Fiction. I am refining and enhancing my (admittedly novice) writing talents under the sage advice of my friends here at Lantern Hollow Press, and with the great many books I am reading from the best authors I can find.
Posted on January 12, 2011, in Erik Marsh, Lantern Hollow Press Authors, Science Fantasy, Science Fiction, science fiction problems, Universes, World Creation, Writing Hints and Helps and tagged Back to the Future, black holes, Kerr, schwarzschild, science fiction, science fiction problems, space time, Terminator, time travel, World Building, worm holes. Bookmark the permalink. 3 Comments.