Lightspeed is Relatively Complicated

Faster Than Light Travel in Sci-fi

The problem with outer space is that it’s too damn big. Really really freaking big. No, bigger than that – keep going. It’s so big, that there’s simply no quick way to get anywhere – it would take hundreds of years to get to another star system even if you could go as fast as light. And Einstein theorized that even approaching the speed of light was physically impossible – exceeding it would require an infinite amount of energy according to his theory of Special Relativity (the exception being certain hypothetical particles, such as tachyons, that always travel faster than the speed of light).

This is a big problem for sci-fi writers, who often like to have their characters do stuff in outer space that involves moving between worlds, between solar systems or, unlikeliest of all, between galaxies. It’s a big problem – truly galactic in its proportions (pun intended). Even light can take a really long time to go places such as between stars or between galaxies. This is why all of those lovely pictures from the Hubble and other deep-space telescopes are always seeing images of things as they looked thousands or sometimes millions of years ago – because they depend on light and the light takes that long to travel to Earth from those places. Can you imagine a sci-fi book predicated on travel taking thousands or millions of years? Well, there have been several, of course, but I don’t think any of them included the kind of space battles or immediacy of action that fans of Star Wars or Battlestar Galactica are used to.

No, if you want to have ships approach each other from more than a few thousand miles away, you really need to speed them up. It took Apollo 11 over two days just to travel from Earth to the Moon, a mere 230,000 miles. It made for a wonderful event back in 1969, but it’s less than ideal for most action-oriented space stories.

So to speed things along, most writers assume (and ask their audiences to accept) that at some point in the future, the light speed barrier is overcome. And it needs to be overcome in a big way – even moving at light speed isn’t all that fast when you account for the enormous size and emptiness of space. To get things properly accelerated, both from a travel and a narrative perspective, you need to move at several times the speed of light. And, ideally, you probably don’t want to deal with Einstein’s theorized effect wherein as you approach the speed of light, you, the traveler, age slowly relative to those who are moving at a more sedate pace. While this works for some writers, typically it’s problematic to have a character zip off to another planet and have everybody he left behind grow old and die.

I’ve got some space-based sci-fi in mind to write, so I’ve been giving this issue some consideration. There’s a tremendous variation in how different writers have solved the faster-than-light issue, but most of the mainstream stuff tends to go for a “Keep It Simple, Stupid” approach. In this paradigm, a ship has engines that produce some sort of faster-than-light effect. In Star Wars they were hyperdrives, in Star Trek they were Warp Drives, and in Dune they used the Holtzman “foldspace” drives (plus a guild navigator who was nicely buzzed on Spice). In most cases the engines either made the ship “go very fast” or they manipulated the fabric of space itself in some fashion, thereby taking a short-cut from where you are to where you’d like to be. Some writers like to really get into the math and physics of how their drives do the impossible, while others just “initiate FTL jump on my mark. Mark!” and zip, off they go. The Battlestar Galactica remake is an example of the latter, where they had FTL engines and an elaborate pre-jump sequence, but never actually explained what the drives did. David Weber’s Honor Harrington series takes the former approach, with all sorts of math and physics describing how Impeller Drives and Warshawski sails get the job done.

Part of the fun of sci-fi, of course, is making up stuff that doesn’t exist but possibly could one day if you accept that a) laws, even laws of physics, are made to be broken, b) people often figure out how to do crazy stuff, and c) there’s so much we don’t know about things like particle physics, gravity, dark matter, and quantum mechanics that just maybe the laws are really more like guidelines after all. And it applies to all kinds of good stuff once you get going. If you’re not limited by what seems plausible, you can create shields of energy, weapons of coherent light or plasma beams, molecular transporters, artificial gravity, and artificial intelligence. Heck, if you’re Gene Roddenberry you can invent cell-phones and PDAs thirty years before they become commonplace consumer electronics.

So there’s my challenge – come up with a way to get spacecraft from place to distant place that’s credible and entertaining, supports the narrative, but has “rules” that don’t allow for too many “it’s magic” cop-outs on my part. Nobody likes it when a writer writes themselves into a corner then taps “magic,” whether in the form of wizardry or technology, to yank key characters out of otherwise certain doom, and FTL travel lends itself to this all too easily. This is a problem that has been solved many times before, which is good and bad. It’s helpful to have models I can look at for inspiration, but it also makes it hard to come up with something that’s unique without being so outlandish that it’s not credible to the reader. I’ll need to strike my balances – technical vs. accessible; easy vs. complex; detailed vs. vague; commonplace vs. challenging (to the characters using it, not to the reader). It’s a fundamental part of the creative process for space-based sci-fi, but it’s also part of the creative joy of writing that I get to build not just whole worlds, but the natural laws under which they operate and the technologies that connect them. As daunting as it may be to overrule Albert Einstein, it’s fun to hold the power of whole galaxies in your mind for a bit and, if you do it well, to take others there with you.