A while back we took a look at space elevators as a way of moving things into orbit from the planet's surface. When you consider the range of activities required for space travel, it turns out that getting into Earth orbit is the easy part. The real difficulty is getting to where you want to go because of one cold, hard truism: Space is big. Unimaginably big. Even if a spaceship averaged 10 percent of light speed (roughly 67 million mph—a mind-blowing feat in itself), it would still take 40 years to reach Proxima Centauri, the nearest star. I don't know about you, but I get restless on a two-hour plane ride.
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Long travel times don't usually align with science-fiction narratives, so writers often employ various cool technologies that allow space travelers to get from here to there more quickly. Let's take a look at some of them.
When Time is of the Essence
A simple solution to avoid excessive travel time is to do away with it entirely. That's essentially what science fiction writers do by using the idea of instantaneous travel. The best and most widely recognized example is the transporter on Star Trek. Now imagine that, instead of beaming yourself between ship and planet, you could travel further, even to faraway planets. That's the idea behind the runcible, a device used in Neal Asher's Agent Cormac series. The runcible allows characters to travel vast distances almost instantaneously. A similar result is achieved through the use of wormholes in Peter F. Hamilton's Commonwealth Saga, a series that plays with themes of alien contact and human evolution. In The Stars My Destination, Alfred Bester's science-fictional retelling of The Count of Monte Cristo, protagonist Gully Foyle is the highly sought-after key to future space travel because he can teleport just by thinking about it. How cool would that be? "I left my wallet at home!" Pop! Pop! "Here it is."
Good Old-Fashioned Space Ships
They say it's not the destination but the journey that matters in the end. That's certainly true in science fiction, where much of the sense of wonder involves travel by spaceship. This is where the time problem rears its head again. If you want space travelers to be alive when the ship reaches its destination, there are two ways to get around the duration problem: either you put the astronauts in some form of suspended animation or you make the spaceship travel faster than the speed of light. Since stories prove to be less dramatic when its characters are asleep, let's focus on faster-than-light (FTL) and other means of space travel.
Star Trek's solution to FTL travel (again, the most well known) is the warp drive, an engine that distorts space-time such that a ship can still interact with normal space. (This mumbo-jumbo is basically a way to overcome the real world relativistic effect of time dilation, which says that those on board an FTL ship experience time more slowly that those who aren't. It wouldn't do for Captain Kirk to return home to find that generations have passed since he began his five year mission and that a bald Shakespearean actor is in command of a new Enterprise!) Science fiction literature, unlike sci-fi television, usually honors time dilation effects.
Timothy Zahn's recent novel Judgment at Proteus employs a train-like Quadrail run by "spiders" to achieve FTL travel, while its protagonist uncovers the mysteries behind ancient alien civilizations. Since there is a train analogue in science fiction, is it any wonder there's a boat one, too? Solar sails offer a means of using light (specifically the projection of photons) to propel a spaceship using radiation pressure. The Mote in God's Eye by Larry Niven and Jerry Pournelle includes the use of a solar sail as both a brake and a weapon. Trains, boats...how about a bulldozer? A ramscoop (also known as a Bussard ramjet) uses electromagnetic fields to collect and compress hydrogen from the interstellar medium to provide spacecraft propulsion. Poul Anderson's novel Tau Zero features a ramscoop, and nicely portrays time dilation as well.
Spaceship travel is not without its shortcuts. If you can't teleport from Earth and don't have the time to travel vast distances, instantaneous travel by spaceship is the next best thing. Consider the gateway, such as that used in Frederik Pohl's classic novel...wait for it...Gateway. Here, humans use tech left behind by a long-vanished alien race, the Heechee, to explore the galaxy. (The modern short fiction anthology Gateways edited by Elizabeth Hull pays tribute to this classic.) Hyperspace is another method employed for quick travel. Here's how it works: Imagine all of space as a flat piece of paper. Now crumble the paper. See how points from opposite ends of the paper are now next to one another? That's the theory behind hyperspace, a method of traveling vast distances by taking a shortcut to a distant point through a higher dimension. Hyperspace is a common means of travel in the Warhammer 40K universe, a vast military science fiction tapestry (which includes the recent novel Pariah) by Dan Abnett.
People Try To Put Us Down, Just Because We Get Around
I said that long travel times don't usually align with science fiction narratives. There's at least one other way that we can travel the vast distances between planets. Next week, we'll take a look at the fact and fiction of generation starships!
John DeNardo is the editor of SF Signal, a Hugo Award-winning group science-fiction and fantasy blog featuring news, reviews and interviews. He also likes bagels.