What If We Could Time Travel?

What If We Could Time Travel?

Throughout history, time has flowed the same way. We spend our first years wishing we were older, then wishing we were younger, wishing we weren't dying, wishing we were dead, and – depending on your religious outlook – wishing we weren't dead.

But what if it wasn't like this? What if time wasn't so linear? What if we could experience time the way we saw fit? What if, We Could Time Travel?

It's a concept well-explored in literature, television and film, but beyond the notions of a plutonium powered DeLorean, a time and space straddling Police Box, a copyright infringing Phone Booth, Rocket Sleds, malfunctioning hot tubs, ancient Japanese scepters, flying against the Earth's rotation, or slingshotting around the sun, it's a mystery which fiction has thus far been unable to crack.

However, beyond the tediously pedantic disclaimer that we are, by nature, travelling through time in a forward direction, science does offer a few theories on the matter. In fact, on a technical level, multiple people have already moved through time at a modified rate – and we call these people “Astronauts”. Rather than the product of a NASA-led dark mission, it's down to the simple fact that objects in orbit – such as GPS satellites – gain 38 microseconds per day. But this isn't likely to impress the lads at the pub.

A beloved chestnut often dug out by hip scientists looking to play their “thinking outside the box” card is the Twin Paradox, which has it that if you spent a year travelling through space at 99.995% the speed of light for a full year, then turned and travelled back to Earth at the same velocity, 200 years would have passed on the planet during the two years you spent away. However, as a time travel method, the Twin Paradox has notable drawbacks. While you don't need to be or have a twin or any other sibling, there is a time investment of two years, coupled with no way to return to your own time.

Another possibility is to employ a wormhole to pass through space-time, however given that you would require some form of advanced spacecraft, and that wormholes as of yet have not been proven to exist, this method too has its shortcomings.

A theory by physicist Frank Tipler – based upon prior work by Kornel Lanczos, and Willem Jacob van Stockum – is equally impractical. Tipler's proposition amounts to a giant centrifuge, with a spaceship orbiting a rod made of material equalling ten times the mass of our sun spinning at a rate of billions of revolutions per minute. Put bluntly, it's not exactly a weekend project.

Meanwhile, modern history's top man for the job, the late Stephen Hawking, offered a suggestion that is just as futile as the Tipler Cylinder, and involves investing more time than the Twin Paradox and offering a lesser return. Instead of orbiting a massive rod, a ship would circle a black hole at light speed for five years, only to stop and find that ten years have gone by, although why exactly it had to be five years for ten, and not one for two, or a week for a fortnight wasn't made clear.

A quicker method might be to stand on a neutron star and attempt to harness its power, however it's much more likely that you would just die and where that would take you is a topic for another day.

However, in addition to being painfully dull, and greatly quixotic, none of these “real” methods allow for a return trip, and thus, don't allow for travelling past-ward.

So, with that in mind, let's settle on ... magic.

Ironically, given science's fixation on moving ahead, philosophical thinking seems to be more fixated on the repercussions of reverse travel.

The first thing to accept upon arriving in the past is you are now most likely in a parallel universe created by your arrival. On one hand, this may be an all purpose time-traveller safety net, but on the other, it's a background notion which a number of popular time-travel theories are built on. The Grandfather paradox, for example, wherein you intentionally or unintentionally kill yourself or prevent yourself from being born, is completely neutered by this parallel universe concept. If you weren't born, how do you exist in any point of time, and if you died how are you alive enough after the fact to pull the trigger?

A similar puzzle is the Hitler's Murder paradox wherein you visit the past to kill Hitler, or any other notable figure from St. John the Baptist to Richard Karn, before they earned their place in history. This plan, as logic would have it, comes undone out of the gate. If these people were removed from history, how were they notable enough for you – in the future – to know who they were? However, this paradox does beg the question – can you kill someone in the past if you've never heard of them? Falling back, again, on the Grandfather paradox, no, probably not. This is because if you go back far enough, effectively anyone that produced a child is likely to be a distant ancestor of yours.

But, if we were to assume that in time all things are possible and that time, uh, finds a way, a whole new set of conundrums present themselves. Assuming you could take out history's biggest baddies, or save its greatest goodies, who is to say we'd be any better off for it in the long term, or that something or someone else wouldn't come along later and drive history in more or less the same direction?

Removed from the constraints of parallel universes, travelling to the past really comes down to two philosophies: either everything you do is a change because you weren't supposed to be there in the first place, or everything you do is fine because clearly you were supposed to be there.

Completing a round trip backward or forward would also create a time-loop, wherein your trip is taking place at two points in history, and is thus perpetually occurring. It's an idea more fleshed out in sci-fi than sci-fact, but related concepts like a causal or causality loop, and self-fulfilling prophecies have been assessed by real world physicists.

As for the future, given that you'd be removing yourself from history, the further ahead you visit the less likely it is that you'd be visiting your future, or at least a future you had much of an impact on. You also couldn't meet yourself, because you're now standing in a universe that you otherwise are not present in. But that's not to say you couldn't roam around for a while and gain some insight, knowledge, or piece of advanced technology while you're there; it just means the future you've witnessed may cease to be once you return to your own time... that is assuming you do return to your own time.

But in any event, what would you actually do if you could time-travel? You could travel back and steal relics that were thought to be lost to time, thus creating what sci-fi would call a predestination paradox. You could stock a bank account, return to the future and collect the interest, or you could scatter definite “of a different time” fashions and trinkets throughout the past for no other reason than to troll the future. Or you could use it in place of conventional travel, setting yourself to arrive in a distant location the instant after you leave the present.

With all this said, responsible time-travel would require a basic set of rules, like keeping a low profile, not participating in historical events, not interfering with or killing majorly influential people, not bringing home a dinosaur, or not getting anyone – including yourself – pregnant. However, the most responsible option may be the one current scientific ponderings leaves us with: visiting the future and making a new life there. After all, from the perspective of the present, the future hasn't been written yet, and the present is wherever you happen to be.