Posts Tagged ‘light speed’

Lighting Out: Interstellar Travel and Warp Speed

January 4, 2011 8 comments


Photo by shamantrixx

Before we can talk about Galactic Science Fiction, we must discuss interstellar travel, which is, after all, a highly improbable engineering feat. Science fiction writers and readers have nonetheless traveled the star lanes for several decades, and galactic SF flourishes even today.

Writers who pursue the interstellar themes have an important choice to make in setting up the premise of their stories. That is, do they observe the Einsteinian (for Albert Einstein) speed limit or not? In Einsteinian theory nothing can exceed the speed of light, which is approximately 186,000 miles per second. The closest star outside our solar system is Alpha Centauri, at a distance of four and a half light-years (a light-year being the distance that light would travel in a year). Most stars are considerably farther away.

Our galaxy, the Milky Way, is approximately 100,000 light-years in diameter, and the distance to the closest full-sized galaxy is 2.2 million light years. The distance to the edge of the universe is estimated at 15 billion light-years. After a point, of course, these measurements have little practical meaning for us.

If we assume the Einsteinian limitation in our interstellar travel, we will need a long, long time to get to even the closest star outside our own solar system. Writers working within the speed of light limitation have tried several approaches to interstellar travel.

Photo by ashmael

One method of travel is by ark, a giant spacecraft with a life-support system that can sustain the several generations needed to travel to a star. This type of craft is sometimes called a “generation-ship.” You will be looking at two examples of travel by generation ship, Heinlein’s “Universe” and Clarke’s Rendezvous with Rama


Heinlein’s work in particular suggests the problems inherent in the generation-ship, both as an engineering possibility and an SF convention. For one, the generations following the first, even though they may not believe in the mission in the same way that the founders did, must still live out their lives on the mission. Succeeding generations become discontent and rebel against the authority of the ship, even though they have, in reality, little choice but to continue the mission. As an SF convention, the generation- ship requires a shift of emphasis from the adventure of exploring new worlds to the social problems the generation-ship creates.

Another method for getting humans across the vast expanses of outer space is to put them in suspended animation so that they can sleep away the time needed to travel. This convention has been used in Alien and Planet of the Apes, just to name a couple of popular movies.

Another solution to the enormous distances lies in the paradoxes of Einsteinian space-time relations. According to the Einsteinian description of space-time, as we increase our speed, the time for the people traveling actually slows down in relation to the people who are not traveling (or who are stationary “relative” to the people who are traveling). At the speeds at which we normally travel, the differences are so tiny as to be incalculable. For example, if the trip that I take from work to home is, say, one billionth of second slower for me than it is for the person waiting at home, then there is no practical consequence.

However, as we approach the speed of light, the slowing of time for the traveler is far more noticeable. In fact, if we were traveling just under the speed of light to Alpha Centauri (four and one-half light-years away), we would experience a passage of time of only days. The people who remained stationary relative to our travel would, however, experience the passage of the entire four and one-half years. This kind of time slippage, however, will not soon be a practical problem for us. The energy needed to move an object at even a small fraction of the speed of light is so enormous as to be technologically unfeasible. We will not anytime soon be traveling near the speed of light.

We can, though, see the problem that such travel could represent for characters in SF. Travelers setting out on a journey of one hundred years are, in effect, saying good-bye forever to all the people they know. What may be only a trip of weeks for them will be a hundred years for the people who stay home. By the time the travelers reach their destination, their friends back home will be long dead and buried.

Through the ‘60s and ‘70s, Ursula K. Le Guin made excellent thematic use of this time slippage in her Hain novels. She even calls her starships NAFALs, an acronym, presumably, for not-as-fast-as-light. Her starships are opposed to those of other SF writers who have FTL ships (faster-than-light). Other SF writers have explored the psychological implications of this time slippage, one notable case being Joan Vinge in The Snow Queen (1984).

Perhaps the easiest way to engage in interstellar travel is to assume that the light barrier can be broken. Many SF writers simply put their starships into space-warp (or hyper-space, or whatever the writer chooses to call the device that enables FTL travel) and get their stories moving. (Star Trek travel is done at warp-speed). At one time or another, some of the best SF talents have, without too much concern for engineering plausibility, taken their characters from one star system to another at speeds greater than that of light.

Yet another way humankind has made it across the enormous distances of space is by teleportation through “gates.” Gates assume a technology that allows the alignment at one locus of two separate places, which may be light-years apart. The traveler merely walks through the “gate” (and, we assume, some sort of energy field) and goes from earth to Mars, or to Alpha Centauri–or to whatever location the machinery is adjusted.

Interstellar Gateway/Wormhole

Photo by JoeJesus

The leap in imagination needed to accept travel by gating doesn’t seem so much greater than for accepting FTL. Still, we associate travel with some form of vehicle, and perhaps gating around the universe defies some deeper level of common sense. A number of pretty good stories have been based on gates (Heinlein’s Tunnel in the Sky, Clifford Simak’s Way Station, and the film, Stargate, to name a few), but gating has not been a major convention in science fiction. Since the days of Jules Verne, extraordinary voyagers have insisted on some appropriately dignified form of transportation—a ship.


One of the earliest galactic civilizations that FTL made possible is in Edmond Hamilton’s stories (1929-1930) about the Interstellar Federation. Headquartered on Canopus, the Federation sent out multi-species crews to patrol the galaxy and to right wrongs.

The name now associated with galactic empires is Isaac Asimov (1920-1992), whose Foundation Trilogy first pulled together a coherent and plausible (at least at the time) version of galactic civilization. Written between 1942 and 1949, the three volumes (Foundation, 1951; Foundation and Empire, 1952; and Second Foundation, 1953) portray a technological civilization in crisis. In Foundation we are introduced to Trantor, the capital city of the empire, itself a lesson in how civilization can become over-centralized. Literally billions of bureaucrats administer the empire in massive buildings from which they can never see the light of day. Evidence of decay lies in the inability of the empire to maintain order on the galactic periphery, as neo-barbarism threatens the peace and order that has lasted for millennia. The analogy is clearly (perhaps too clearly) based on the Roman Empire and its collapse in the face of the Germanic invasions.

One visionary, Hari Seldon, through the “science” of psychohistory, attempts to forestall the eventual collapse of the empire that will result in so such great destruction. He establishes a tiny settlement on the edge of the galaxy, which has the ostensible purpose of preserving the cultural heritage of the empire by compiling the Encyclopedia Galatica. His true intent, though, is to establish the nucleus of a new order that will survive the coming destruction. The adventures of the Foundation in that far future make for fascinating reading.

The virtues of the new order, the Foundation, are strikingly similar to virtues of post-World War II America—gumption, get-up-and-go, free enterprise, and the establishment of new markets. Because Asimov reveals a future that is strikingly analogous to corporate America, some readers are uncomfortable with what they see as a dated ideology.

But whatever the deficiencies in Asimov’s work that we see in retrospect, he is nonetheless important for establishing the major features of galactic SF. His Foundation Trilogy is the kind of SF that many contemporary SF writers grew up on. Their work now wouldn’t be the same without him, and Asimov is an indispensable influence in the development of SF during the so-called Golden Age.


Planetary SF allowed several new places to set a story, but those new locations were used up pretty fast. SF writers needed new locations, and interstellar travel supplied them in virtually an infinite number. Writers—with Asimov leading the way—soon mapped and established the rules for using this new space.

Given the progression from lunar, to interplanetary, to interstellar SF, we might wonder about the development of inter-galactic SF. Stories here and there deal with travel between galaxies, but writers by and large have not developed any special or important themes that would require travel between galaxies.

-Steve Anderson