Physicists don’t make it easy for sci-fi writers, not those who want to write about time travel, that is. Yes, they allow us a few, measly possibilities – you could drag one end of a wormhole off on a near-lightspeed round trip (if you could build a wormhole and if you could find a way to drag one end of it), you could build a contraption that exploits frame dragging by rotating laser cylinders (if you had near-infinite amounts of energy at your disposal), or you could try transferring information through time with tachyons (if such particles even exist), but that’s about all the options you get.
Yes, you can wave your arms and talk quickly about the missing singularity in loop quantum gravity, hop into a black hole and Bob’s your uncle, but, if you want to stick with real physics, even the wildly speculative stuff, time, my friend, is a bitch.
And yet we love the knots that chrononauts tie themselves into as the paradoxes pile one upon the other. We love the idea that, if you could just go back and do that one thing differently, or go forward and see how it all works out, our lives – everybody’s lives – could be so much better.
Time travel is about abolishing regret, righting wrongs, avoiding terrible mistakes. And if that means a journey in time must defy the laws of the Universe, then punch in the destination, throw the lever, and let’s be off.
For those unencumbered by any knowledge of physics, time travel is as easy as pie. There are countless stories of magical transportation between the ages. These paranormal “timeslip” stories with their magical objects, portals, or “gifted” people don’t get hung up on temporal anomalies, focusing instead on the Roman legionnaire’s oiled muscles, or the Byronic curls of a Mr. Darcy lookalike’s untameable hair. (I mock it, of course, but for a really good timeslip novel, try Daphne du Maurier’s The House on the Strand.)
Science fiction writers have only three ways of coping with the miserable paucity of physically plausible time travel methods. The first is to just suck it up, drag that wormhole, fly through the black hole (with your despaghettification shields on max), and reply with “quantum weirdness” whenever awkward questions are asked on fan forums. My all-time favourite SF novel in this category is Gregory Benford’s Timescape, wherein a future scientist warns us of the catastrophic ecological mistake we’re all about to make, by sending messages on a beam of tachyons. Sadly, we now know that even 10,000 climate scientists yelling “Don’t do it!” at the tops of their voices for two decades isn’t enough to avoid an ecological disaster, let alone a few time travelling tweets in Morse code.
The second technique for avoiding physical constraints on time travel, is simply to blast through them with unshakeable confidence that every problem can be solved. Of course we’ll go faster than light one day, we just need bigger engines. Brain uploads? Sure! I give it a couple of decades. Because, you see, progress transcends everything and the human spirit is unstoppable. In a world where few of us understand how any of our technology works, it might as well be magic. Science, many say, is just another belief system. And, if we believe hard enough, anything could happen. It’s how Star Trek does time travel. You slingshot around the Sun and – hey presto! – you’re flying backwards in time (see also, Superman).
The final technique is to use superscience. Superscience is like magic but not really. It’s the science of the far future, way beyond our understanding (like Michael Moorcock’s power rings in The Dancers at the End of Time), or it comes from an alien race (like the “time gate” in Heinlein’s “By His Bootstraps”, and Dr Who’s TARDIS – Star Trek also used alien portals for time travelling), or it is the work of brilliant genius (H.G. Wells’ time machine, or Back to the Future‘s de Lorean, for instance – or the “lob site” in my own series, Timesplash).
In many ways, superscience is the most satisfactory solution to time travel. In the absence of any real science, it allows us to explore this magnificent literary device while never surrendering the principle that all phenomena are, at root, natural, explainable, and manipulable by anyone with the knowledge and the equipment – in theory, anyway.
(This post first appeared in SF Signal.)