Time travel has fascinated people for millennia, beginning with old folk stories and myths, and continuing on into the 21st century in the form of novels, television shows, and motion pictures. Every Christmas in English speaking countries we are treated to two perennial movies which feature time travel. In Charles Dickens’ A Christmas Carol, spirits take Ebenezer Scrooge into both the past and the future. In It’s a Wonderful Life, an angel conducts George Bailey on a trip into the past and future-a past and future that would have occurred had there been no George Bailey.
Like these examples, time travel in fiction was long accomplished either through supernatural means or through mysterious and unknown means. In A Connecticut Yankee in King Arthur’s Court by Mark Twain, the protagonist is transported instantly from 19th century Connecticut into 6th century England by a blow on the head from a crowbar wielded by an angry employee. How did he return? After being stabbed while attending to the wounded on a battlefield, the sorcerer Merlin cast a spell on the traveler so that he will sleep for 1300 years before waking up. In the 1889 novel, Mark Twain used a literary device often employed in time travel stories since-physical evidence of the trip-proof (at least to the protagonist) that the journey had not been an illusion. In Twain’s book, that physical evidence was a bullet hole in a suit of medieval armor in a museum. A hole that the time traveler himself had made 13 centuries before with a revolver that he had fashioned using his knowledge of 19th century technology. In H.G. Wells’ The Time Machine, published six years later, Wells used the same device, in this case two withered white flowers the time traveler had absently brought back from the year 802701. Two flowers unlike any known in the 19th century.
Wells was the first novelist to have his protagonist use a machine, therefore moving time travel from the fantasy to science fiction genre. It’s awfully hard for a reader-even of what is represented as fiction-to believe that time travel can be effected by a blow on the head with a crowbar. That requires a whole lot of the suspension of disbelief. But travel by means of a machine is much easier to believe. The device described in The Time Machine had only two controls, both small levers that the traveler could unscrew and put in his pocket to prevent an unauthorized person from using the machine. One lever sent the machine forward in time; the other backward in time. Wells’ time traveler said that it took him two years to construct the fabulous machine, but never said what its power source was or anything about the principles of physics involved. There are two reasons why none of this vagueness detracts from Wells’ book. First, the book was published well over a century ago, when the only air travel was accomplished via an occasional hot air balloon, land travel was by horse or rail, and the telegraph was the most advanced form of communications. Even had Wells formulated a scientifically plausible and detailed explanation of how such a machine might be constructed and powered, it would have been lost on the reading public of 1895. Second, there are the matters of Well’s magnificent imagination and his prodigious skill as a writer. Few writers of any generation can match those.
For those of us writing today more effort and attention to detail is necessary. We can’t get by with a blow from a crowbar or with the simple bare sketch of the device described by Wells. Our readers don’t live in the 19th century, but in the 21st. One of the very things that made Star Trek such a wildly popular television series with spinoffs galore was its attention to scientific detail. Of course some of the physics involved was far out, but it was always plausible, always built on a solid base of the real physics which its fans had learned in high school or college or through reading about NASA’s latest projects or in many other ways. This made the series more believable, more satisfying and pleasurable. There is a lesson in this. If in the science fiction we write, we offer the reader 85 or 90 percent solid physics and make sure that the remaining 10 or 15 percent is plausible, we’re on the right road.