Faster than Light in Real Space
Science fiction couldn’t exist without a means of quickly reaching distant stars. Some authors accomplish that by using wormholes, hyperspace or any other method of reaching a destination without actually traveling through the space separating the point of departure from said destination. Many, however, use faster than light travel.
I’m going to leave the technological considerations aside for now. Whether it might or might not be possible to achieve such a feat is less important. I’ll just assume that it is possible, because this is about science fiction and therefore hypothetical.
In assuming that it is possible, I’m assuming that sufficient thrust can be generated and that there are means of preventing everything, including the crew, from imploding. Those are technical problems and therefore not my focus.
What I’m looking at are the logical problems. One would involve the time spent accelerating and decelerating, as it would make very little sense for these processes to be instantaneous even if it would be technically possible, but this is less important and perhaps less obvious than something else. I’m talking about the risk of collision, and that’s what this post is really about.
In the books and movies which use faster than light travel through real space, there is usually talk about setting or plotting a course before such a speed is reached. That’s supposed to mean telling the computer to figure out a route to the intended destination which avoids any bodies the ship could collide with. But this is where the problems really begin…
How do you know exactly where everything is? You’d need a constantly updated map of every single body in the galaxy, and that’s only if you confine yourself to this galaxy. At a glance, that means every single star, planet, satellite, asteroid, comet and so on. Of course, you could eventually have an accurate map of the galaxy, but how do you obtain it? You’d need to send ships to explore first, and those ships would need to travel slow enough to avoid any collisions with unknown bodies, making the task take an extremely long amount of time. There is the possibility of sharing star maps with other civilizations, of course, but you’d better be very sure they’re accurate before you rely on them!
Now let’s assume that you do have that perfectly accurate star map and run simulations to know where each body should be at that specific moment. But what if it isn’t? What of gravity fields interfering with smaller bodies? Up to a point these could be calculated I guess, but then it gets even worse. What of collisions between celestial bodies or, more importantly, the intervention of other species? How can you take that into account? What if someone decides to push an asteroid out of the way since was coming too close to their planet or space station? What if they were doing target practice on another? What if we’re talking of civilizations, such as our own, which are yet to establish contact with others? Those couldn’t let you know even if they wanted to, so you could never update your charts!
And speaking of other civilizations, what of the things they actually build? Space stations, probes, ships… You could assume that space stations are very close to planets, so if you avoid the planet you also avoid the station, but even civilizations which are barely taking their first steps through space could send probes anywhere, even outside their own solar system. Our own are certainly proof of that… As for ships, there is absolutely no way to know where those are. Advanced civilizations, capable of faster than light travel, could have plenty of ships which could be anywhere at any moment. Space may be big, but there is no way to be absolutely sure there won’t be two ships in the same place at the same time. The chances of that happening increase drastically when you near certain “popular” destinations, which multiple civilizations have a reason to visit frequently.
After establishing that you can’t avoid the dangers by simply setting a course, we have to think of the alternative: Being able to detect an object early enough to avoid a potential crash. After all, computers could react very quickly and therefore be able to steer the ship clear of surprising obstacles even at very high speeds, right?
Not quite, I’m afraid… The easiest things to spot are the ones which would be easiest to avoid by simply plotting the course. Stars should certainly be avoidable even at extremely high speeds, but as the size of the body in question decreases and its speed increases, it becomes increasingly difficult to keep the ship safe. Yes, if we assume that faster than light travel is possible, we could also assume that very powerful scanning systems might eventually be able to notice any celestial bodies in time to avoid a collision… But I doubt that any system could notice another ship which also travels much faster than light. That could require scanning an area with a radius of many light years every single moment and also correctly judging what the other ship will do next, since its own attempts to avoid a collision might actually cause it.
These are just a few thoughts I’ve been having these days. I’m sure there are also plenty of other problems, and that’s without even taking the technological ones into account.
For this reason, I dare to make the audacious suggestion of eliminating the concept of faster than light travel in real space from science fiction. Yes, it could be possible, but it’d be too risky to try over long distances. And since long distances are exactly the ones it’d be developed for, it seems quite pointless. There must be better ways and any race which is advanced enough to create ships capable of traveling much faster than light would have likely found them.
There are a lot of other paths to explore when it comes to traveling such immense distances… I mentioned wormholes and hyperspace at the beginning of this post and I believe those are the two main concepts, but they could take many forms and could be exploited in many different ways, so I don’t think anyone should feel limited if they need to remove the ability to travel faster than light from their works.
