Your machine is built. Where now? The last days of the Roman Empire? The Dark Ages? Or that terminal beach at the Heat Death of the Universe? The Dark Ages. Good choice.
Temporal camshaft. Check. Fourth-dimensional perambulator. Check. Ignition. Check. Ignition?! Hang on a minute. Exactly how are these time machines meant to work?
One of the very first time gadgets was invented by Charles Lutwidge Dodgson, better known as Lewis Carroll. His idea, The Outlandish Watch. Appearing in Carroll’s Sylvie and Bruno (1889), the watch had two modes. If the reverse peg is pushed, then “events of the next hour happen in reverse order”. The other mode involved the watch’s hands. They could be moved backwards, as much as a month, enabling the wearer of the watch to travel into the past.
You’re not, of course, going to find one of these little beauties at the local jewellers. And the device’s owner, a Professor for heaven’s sake, is frustratingly elusive when asked to describe the theoretical basis for the thingamajig, “I could explain it, but you would not understand it”.
Wells fared no better. He wisely left the details of his time machine extremely fuzzy. It was left to others to figure out. French writer Alfred Jarry stuck his neck out in a review of Wells’ Time Machine pithily titled A Commentary to Serve for the Practical Construction of the Machine to Explore Time.
Wells had talked vaguely of levers. But Jarry unduly designed his machine with three rotating gyrostats. He even included an impressive nonsense diagram. Jarry figured that a time machine would have to anchor itself absolutely in space in order to move in time. In this way, he says, “all future and past instants … would be explored successively”.
Kurt Vonnegut’s race of fictional aliens, the Tralfamadorians, had gone even further. With no contraption of any kind, they were naturally able to see along the timeline of the Universe. They not only had the ability to experience all four dimensions. They also had total recall of both past and future. The human view of time is a mere snapshot. The Tralfamadorian’s is that of a movie, in which all scenes are played out at once.
In effect, Einstein had died a Wellsian. He wrote in 1955 that relativists understood the division of past, present and future to be a mere illusion.
So, how feasible is Wells’ fictional trip into the far future? Professor of Theoretical Physics, Paul Davies, addressed such questions in his 2001 book, How To Build a Time Machine. If we want to travel into the future, all we need is a machine that can move at a velocity close to the speed of light. As our spaceship approachs this speed, the slower time moves. Once you get back to Earth, you will hardly have aged. Decades, or even centuries, will have passed ‘back home’.
According to physicist J Richard Gott in his 2002 book Time Travel in Einstein’s Universe, travelling back in time is far trickier. It entails fiddling with wormholes, cosmic strings or black holes. These are the kind of time machines feasible only with mind-warping technology.
And in 2007, American scientist Ronald Mallett broke the news of his life-long struggle to build a time machine. Mallett’s take on temporal travel is to bend spacetime. Massive objects such as stars and planets do. Mallett is among those who believe that light too can bend the continuum.
So, rather than the De Lorean envisaged in the Back to the Future films, Mallett’s machine is a ring laser, an extremely powerful one. And maybe one day, by simply popping into this huge vortex of light, travel through time may be possible.