World, Media

The timeless appeal of time travel

By Rebecca Davis 17 May 2012

What is the one thing you would do if you could go back in time? In Stephen King’s latest blockbuster, 11.22.63, his protagonist tries to prevent the assassination of John F Kennedy. The book flags a little – unlike the perpetual attraction of time travel. By REBECCA DAVIS.

11.22.63, published late last year, is Stephen King’s 56th book. Throughout his career, King has churned out novels of vastly differing quality, though they all tend to shoot straight to the top of the bestseller charts. 11.22.63 is somewhere in the middle. It lacks the narrative brio of some of his classics, is at least twice as long as it needs to be, and there’s a sense that King occasionally gets tripped up by the complexities of his own plot. But what makes the novel a gripping read nonetheless is the premise that drives it: time travel.

Why are we so nuts about it? Addressing this question at a Philosophical Society meeting in Cape Town this week, UCT philosopher Dr Jack Ritchie suggested that much of its appeal lies in the potential it offers to rectify past mistakes. “Maybe I could go back to 1991 and tell myself not to grow a ponytail,” Ritchie mused wistfully.

In the scenario set up by King’s novel, the protagonist has little choice in the matter. A dying friend alerts Jake Epping to a wormhole that connects 2011 and 1958, and pleads with Epping to return to this time in order to complete the task he failed to carry out: prevent Lee Harvey Oswald from shooting JFK in Dallas in November 1963.

Epping’s friend’s theory is that if JFK had not been assassinated, the US would not have entered the war in Vietnam, and a host of other negative knock-on effects (such as the assassination of Martin Luther King) would not have happened. He convinces Epping of the righteousness of the mission to save JFK’s life.

Trying out the wormhole, Epping discovers a secondary allure: he is also charmed by late-50s, small-town American lifestyle. For one thing, he can live like a king by placing bets on the outcome of sporting fixtures, having researched these before entering the wormhole.

King’s wormhole – his version of a time machine – works along lines that we’ve seen many times before in literature and pop culture. Once you’ve entered the wormhole, however many hours, days or years you spend in 1958, only two minutes pass in 2011. An interesting spin King adds to the equation is that every time you return to 1958 from 2011, it functions as “a complete re-set”.

In other words, if you make changes to the 1958 universe, return to 2011, and then go back to 1958, the changes you made on your last trip there are totally erased by your return. You will always go back to the same day in 1958, in identical circumstances.

Some of the most satisfying parts of the novel have to do with Epping’s sense of himself as an anachronism in 1958, and his attempts to hide this. His friends and neighbours can sniff that there is something different about him, but can’t put their fingers on it. He has to watch his language use, because much of his slang is unfamiliar to them. He is horrified by the racism he sees in pre-civil rights America, and frustrated by the backwardness of their medical procedures. When disaster strikes, he yells at a passer-by to “call 911”, but the emergency number was only introduced a decade later, in 1968.

The interesting question that the book poses, however, has to do with the question of causation in time travel. Epping assumes that if he goes back in time and stops Lee Harvey Oswald, the world will turn out to be a better place in the future. Many people say that if they could time travel into the past, they would kill Hitler for the same reason. King’s plot suggests, however, that things don’t necessarily work like that.

The incomparable sci-fi writer Ray Bradbury’s short story A Sound of Thunder (1952) deals with the issue of time travel causation in a more succinct and dramatic form. Most modern conceptions of time travel in literature take this story as their guide. It also represented an act of time travel into the future, because the story anticipates the concept we now know as the “butterfly effect”, even though the term was only coined two decades later.

A Sound of Thunder is set in the year 2055, where a man called Eckels pays to go on a “time safari” to the Jurassic period in order to shoot a dinosaur. Before they arrive, 60 million years earlier, the hunters are warned not to stray off a floating path laid six inches above the earth for any reason. “Why?” asks Eckels.

The safari leader responds: “We don’t want to change the Future. We don’t belong here in the Past. The government doesn’t like us here. We have to pay big graft to keep our franchise. A Time Machine is finicky business. Not knowing it, we might kill an important animal, a small bird, a roach, a flower even, this destroying an important link in a growing species.”

Eckels agrees not to leave the path, but when he is confronted by a fearsome Tyrannosaurus Rex, he loses his nerve and stumbles off the path to hide.

The safari guides are furious with him, but they re-enter the time machine as planned and return to 2055. As soon as they alight, however, it becomes clear that something has changed: “What sort of world it was now, there was no telling”.

The first giveaways are reasonably innocuous: a different man behind the office desk, a sign painted on the office wall now says “Tyme Sefari” instead of “Time Safari”. Then they discover that the results of the previous day’s presidential elections have gone the opposite way, and a “militarist, anti-Christ, anti-human, anti-intellectual” wannabe dictator has been voted in. Falling into a chair, Eckels examines his boots and finds, embedded in their mud, a dead butterfly.

In Bradbury’s conception, then, you don’t have to go as far as assassinating someone – even the tiniest action while time travelling to the past can have drastic impacts on the future. But both cosmologists and philosophers have wrestled with the question of this kind of causation, and their conclusion is: it simply can’t work that way. To quote Stephen Hawking: “This kind of time machine would violate a fundamental rule that governs the entire universe – that causes happen before effects, and never the other way round”.

Back at the Philosophical Society, Ritchie explained that the problem is summed up by a famous thought experiment called the Grandfather Paradox. It works as follows: I build a time machine and travel back to 1945 to find my grandfather, and I kill him before he conceives my father. But if my father is not born, then I am never born either – so I could never have killed my grandfather. In order to kill my grandfather, I must not have killed my grandfather.

The whole thing is impossible, and, taken further, it applies to any action of this kind we might want to take in the past.

Stephen Hawking calls this “the sort of situation that gives cosmologists nightmares…I believe things can’t make themselves impossible. If they could then there’d be nothing to stop the whole universe from descending into chaos”. Other physicists maintain that the past and future do not have to be consistent in the way that the Grandfather Paradox requires.

Addressing this question in an interview in 1999, Carl Sagan said: “I know the idea of the universe having to work out a self-consistent causality is appealing to a great many physicists, but I don’t find the argument for it so compelling. I think inconsistencies might very well be consistent with the universe.”

The Grandfather Paradox is not the only reason why Hawking believes time travel to the past – at least through wormholes of some kind – to be unfeasible. He also holds that quantum physics makes the possibility unavailable, because a wormhole that would expand to a sufficient size to enable time travel would be destroyed by looped radiation.

A slightly odder reason Hawking has advanced to counter the possibility of time travel to the past is the fact that we do not routinely encounter thousands of time travelling tourists from the future. This point was bolstered in 2005, when the Massachusetts Institute of Technology threw a “Time Traveller Convention” in the hope of luring guests from the future to their campus on a certain date and time.

A Wired magazine article from the time explained what happened: “When attendees gathered outside for a raucous countdown at 10pm Eastern Standard Time, nothing appeared on the makeshift landing pad at the co-ordinates Dorai set for the time travellers. Fog from an aqueous smoke machine rolled across the empty landing area, which lay at one end of a sand volleyball court in the East Campus courtyard. One person in the crowd shouted, ‘Happy New Year’, while another suggested the time travellers may have mistakenly set their watches for Central Standard Time. A group of students then raided a plate of treats set out for the time travellers, while others snapped pictures of the scene with their cell phones and digital cameras.”

But Carl Sagan said it proves nothing that we haven’t yet encountered anyone from the future. For a start, how do we know we haven’t? “There’s the possibility that they’re here alright, but we don’t see them. They have perfect invisibility cloaks or something. If they have such highly developed technology, then why not? Then there’s the possibility that they’re here and we do see them, but we call them something else – UFOs or ghosts or hobgoblins or fairies or something like that.”

The good news for time-travel aficionados is that philosophers and physicists alike are much more upbeat about the possibility of time travel to the future. In fact, as Ritchie points out, future time travel is already a potential in our universe. We can do it, theoretically at least, via suspended animation (cryogenics, in other words – freeze ourselves and wake up in the future, unchanged), or we can do it by simply travelling very fast.

If we travel on a rocket and get up to a velocity near the speed of light (almost 300,000km per second in vacuum), we begin to travel in time: time slows down on board the rocket in order to preserve the speed of light, which underpins the laws of known physics. Hawking estimates that in the case of a rocket travelling at 99% of the speed of light, one day on board would be equivalent to a year’s worth of time passing on Earth.

But of course, that wouldn’t be the fun kind of time travel, at least as it’s envisaged here. That would be just messing with time, and you’d have the Rip van Winkle-esque problem of returning to a changed landscape, where everyone you knew and loved is old and wrinkled.

Nonetheless, as things stand, we can conclude that travel to the future is still more likely than travel to the past. And even if the latter were to become a reality, you probably couldn’t go back and stop Lee Harvey Oswald anyway. Ritchie summed it up as follows: “Time travel might be possible, but you can’t do the kinds of interesting things you might hope for.”

At least we still have the consolation of fiction. DM

Read more:

Stephen Hawking: How to build a time machine, in the Daily Mail.



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