Within the specific genre of science-fiction, fantastic tales of time-travel to the far-flung future or to the distant past are hardly rarities. Take, for example, H.G. Wells’ epic novel of 1895: The Time Machine. The book tells the story of a brilliant, London, England-based scientist, inventor and adventurer who journeys to the year A.D. 802,701 where, to his complete and utter dismay, he finds that the Human Race (in the form that we understand it, at least) no longer exists. In its place are the Eloi and the Morlocks. The former are relatively human-looking beings (albeit of smaller stature), yet they utterly lack vitality, imagination, and any desire to learn or advance. The Morlocks, meanwhile, are fearsome, savage and nightmarish beasts who dwell in darkened underground lairs and who use the Eloi as we use cattle: namely, as a source of food. In the 1968 movie, Planet of the Apes, Charlton Heston’s character, Taylor, a NASA astronaut, arrives on a nightmarish world run by a ruthless race of talking apes. Only at the film’s climax, as he stumbles upon the broken remains of the Statue of Liberty, does Taylor realize with horror that he has not set foot on some far-off planet, after all. Rather, he is home, 2,000 years in the future and after a worldwide nuclear holocaust has destroyed human civilization and given rise to the world of the apes.
Then there is The Philadelphia Experiment: an entertaining Hollywood film allegedly based on real events, and which tells the story of two sailors – David Herdeg and Jim Parker – who are propelled through time from 1943 to the Nevada Desert, circa 1984. And we should not omit the BBC show, The Flipside of Dominick Hide, in which the main character travels through time from A.D. 2130 to London, England in 1980. Ostensibly there to observe the transportation systems of the past, Hide subsequently finds himself on a quest to locate one of his distant ancestors. Let’s not forget Michael J. Fox’s character, Marty McFly, who in the 1985 Hollywood comedy blockbuster, Back to the Future, travels through time to 1955, where he almost makes out with his then-teenage mom, comes perilously close to wiping out his own existence as a result of his time-traveling antics, and single-handedly invents rock ‘n’ roll. And, there was Déjà vu, with Denzel Washington, a 2006 movie which told the story of U.S. Government agents trying to solve a terrorist attack by using secret time-travel technology to look into the past. And who can forget 12 Monkeys, starring Bruce Willis? In other words, at least as far as mega-bucks movies and literary classics are concerned, the theme of time-travel is a spectacularly successful one.
Tales of fictional time-traveling heroes and strange futures aside, what of the real world? Is it possible that one day we might travel through time in much the same way that today we hop on a plane to take our yearly vacation? "Time travel is not theoretically possible, for if it was they’d already be here telling us about it," British physicist Professor Stephen Hawking famously said a number of years ago. And even if time-travel did one day become a possibility, it would be beset by major problems, as Hawking noted: "Suppose it were possible to go off in a rocket ship, and come back before you set off. What would stop you blowing up the rocket on its launch pad, or otherwise preventing you from setting out in the first place? There are other versions of this paradox, like going back and killing your parents before you were born."
Mac Tonnies, the late author of the book After the Martian Apocalypse, which is a study of the controversial "Face on Mars" mystery, believed he had the answer to the potential problems cited by Hawking: "Stephen Hawking condemned time travel because, in his opinion, it should enable a constant stream of visitors from our own future. He assumes, perhaps unwisely, that we'd be aware of these visitors, when in truth it's remarkably easy to think of reasons our ancestors might choose not to visit at all." Tonnies continued: "Other physicists are at work refuting the paradox of going back in time and killing your parents before you are born. If they're right, a time traveler from the future could interact with others, including his or her past self, so long as no action was taken that would endanger the traveler's own continued existence. It's difficult to visualize how this might work, although the idea makes logical sense. Maybe the best analogy would be a physical system that relies on a principle of least action, such as a ball rolling inexorably downhill."
He further noted: "The fascinating upshot of this is that there's a chance we're indeed being visited by advanced beings from our own future, but their interactions with us would be necessarily limited lest they doom themselves to nonexistence." Tonnies also wonders if the many UFO sightings that have been reported for decades may not be due to the actions of aliens from the other side of the galaxy, but the result of time-traveling humans masquerading as ET to keep secret their real point of origin. "If time travel is possible," said Tonnies, "the behavior of UFOs may be at least partially explained: formal contact with us would result in a causality violation of some sort, so they must remain content with maintaining their presence behind a curtain of subterfuge."And if we are indeed being visited by time-travelers from the future, then surely the biggest question is: how are they getting here? One possibility is by what is known in physics as wormholes, a term coined in 1957 by theoretical physicist John Wheeler.
The wormhole is basically a shortcut through both space and time; and although firm evidence for the existence of these so-called "time-tunnels" has not yet been firmly proven, they do not fall outside of the boundaries presented in Einstein’s theory of general relativity. Indeed, in 1988, Kip Thorne, a gravitational theorist at Cal-Tech demonstrated that wormholes, if they existed, could be kept open by using what is known as Casimir Energy, or exotic matter. The Casimir Effect is based upon a force that is exerted as a result of the energy fields that exist in the space between objects. And, of course, if such exotic matter could be harnessed and controlled, then for our time-traveler of the future, taking a trip into the past via a wormhole may be relatively commonplace. Jenny Randles, the author of a number of books on time-travel, including Breaking the Time Barrier, Time Storms, and Time Travel: Fact, Fiction & Possibility, offers a cautionary view on traveling through time: "The ability to manipulate time would provide a dictator with the ultimate doomsday device: allowing one to change the past or adapt the future until it suited his or her own ends." And as Randles perceptively notes: "Human society will face many difficult questions when that first time machine is switched on. Like the first moon landing, the discovery of time travel will change our world."
The idea of time-travel fascinates us because it offers us the possibility, however remote, of revisiting and recapturing a moment from our past: the very first time we got laid, the day we bought our first car, that special night when we first got the chance to chug down a long, cold one. And, if time-travelers from our future are secretly visiting us already, as Mac Tonnies suggests as a possibility, at least it shows we have a future!