Try as we might, we simply, can’t beat the speed of light: 186,000 m.p.s. That’s the cosmic speed limit, imposed on us by the immutable equation, E=mc².
Yet, most “ships of the imagination”—to borrow a phrase from Neil deGrasse Tyson—invented by science-fiction writers and Hollywood screenwriters, continue to enthrall us with their ability to travel at superluminal speeds, making journeys from one star system to another look like milk-runs.
So, what gives? What happens is that they only appear to travel faster than light. The spacecraft, themselves, don’t generate horsepower of that incredible magnitude. Instead, they twist and bend the space around them and it’s that distortion of space-time that provides the propulsion.
Warp drive—a propulsion technology, popularized by “Star Trek”—moves a vessel by contracting the space in front of it and expanding the space behind it, thereby, creating a powerful wave, which thrusts it to its destination. The craft, itself, remains ensconced in a “bubble” of normal space-time.
Our nearest star, Alpha Centauri, is about 4.3 light-years away. A one-way trip there, using the technology we have now, would take us roughly 80,000 years.
If, however, you were a passenger on board the U.S.S. Enterprise and were traveling at warp factor 1 (which is equal to the speed of light), then, you’d get there in 4.3 years. At warp factor 8 (which is 512 times the speed of light), you’d arrive in a swift, three days. Considering the immensity of the distance involved—nearly 6,000,000,000,000 miles—that time is no more than the blink of an eye.
A wormhole is a fascinating mode of faster-than-light travel, but that just might involve hurtling into a black hole. Understandably, spaceships don’t dare to take that route for fear that they’d be sucked into it, get “spaghettified,” and be rendered into nothingness.
In principle, a black hole (a region of space-time from which nothing can escape) could be connected to a “white hole” (a region of space-time into which nothing can enter, but can only escape from). The tunnel between the two, opening in locations, light-years apart, popularly called a wormhole, could serve as a cosmic interstate. A vessel would enter it, cross it, and emerge from it at a speed lower than that of light.
So, then, neither of these faster-than-light technologies breaks the theory of special relativity.
The jump drive is yet, another manner of space travel. It’s similar to warp drive in that it uses faster-than-light technology—but there’s a difference. It allows a starship (or, any matter) to be teleported from point A to point B, instantaneously. In “The Hitchhiker’s Guide to the Galaxy,” Douglas Adams christens it the “Infinite Improbability Drive.”
In Madeline L’Engle’s “A Wrinkle in Time,” the three old ladies, Mrs. Who, Mrs. Whatsit, and Mrs. Which, take Charles, Meg, and Calvin on a tour of strange worlds through “folds” in space-time, a topological feature, akin to a shortcut. She calls it a “tesseract.”
A spacecraft can, altogether, bypass regular space-time and enter an alternate dimension, known as “hyperspace.” We’ve seen that in “Star Wars,” “Stargate,” “Babylon 5,” “Cowboy Bebop,” among many other series.
Not all science-fiction, however, features spaceships that beat the speed of light. In such cases, their journeys seem to last for an eternity. And for their crew to be able cope with the immeasurably long flight time, they’re put in hibernation as in Stanley Kubrick’s “2001: A Space Odyssey” (1968).
The three scientists on board the nuclear-powered Discovery One are placed in suspended animation during the voyage to Jupiter so that when they wake up, the flight time would seem shorter from their perspective.
Arthur C. Clarke’s “Rendezvous with Rama” centers on a giant “generational ship” that’s been going relatively slowly for some 200,000 years, at least.