It's just a Question of Time
Image Source: http://www.sxc.hu/photo/782175
The universe and our planet may be billions of years old, but human lives are measured in much smaller increments. Except for a tiny percentage of people, few of us spend longer than 100 years on this planet: little time to experience the breadth of its future or past. This lack of longevity may help to explain why our species is so obsessed with the idea of time travel. But for the most part, time travel has remained a fictitious preoccupation.
However, as of last year, we can at least imagine the possibility. In May 2010, world famous physicist Stephen Hawking published an article in a British newspaper that set out his case for believing it to be – theoretically at least – possible1. But rather than building on the wormhole theories popular with some scientists – where tiny breaks in the structure of the fourth dimension are artificially inflated to allow us to step through and access earlier events in our history – Hawking contends that ‘like a microphone at a rock gig’2 time is susceptible to feedback. Sound entering a microphone from a speaker causes a loop and that loop creates the screeching sound of feedback.
Similarly, opening and stepping through a wormhole into the past would create a feedback loop of radiation that would destroy the wormhole. Most probably before you even had time to use it as a gateway. Instead, if we were to travel in time, the article contends, it would be into the future.
The theory is both simple and mind boggling at the same time: that time flows at different speeds, according to principles set out by Einstein. Simply put, time runs faster in space than it does here on earth. The mass of the planet effectively weighs time down, or as Professor Hawking states: “Einstein realised that matter drags on time and slows it down like the slow part of a river. The heavier the object, the more it drags on time. And this startling reality is what opens the door to the possibility of time travel to the future.”3
This is why the Global Positing Systems satellites that circle the earth have to be recalibrated every day. In orbit above us, their day is approximately a third of one billionth of a second shorter than ours because time is running faster.4 It’s not a lot but it’s enough to throw out the positioning data by nearly 10km per day with potentially catastrophic results: an aeroplane following a GPS beacon into JFK International Airport in New York would be informed to land in the inhospitable waters of the Atlantic Ocean instead of touching down safely on the airport tarmac.
In theory, the extreme mass and gravitational pull of a black hole – where even light is unable to escape –would slow time. Of course, Professor Hawking makes the point that black holes are fairly useless time machines. They don’t help you to journey anywhere, just to experience time at a slower rate. If you managed to escape and get back to earth you would find you had aged less than those you had left behind on the planet.The trick, then, is to move at colossal speed, as close to the speed of light as is possible. Because here time starts to slow and you start to move into the future. In the Daily Mail article Hawking uses the analogy of a superfast train. Accelerating towards light speed, they would soon experience a year of our time in what they perceive to be a day. In a week of travel they could move as much as 100 years into our future.
No such superfast train or space ship currently exists. But the purpose of the large hadron supercollider at CERN in Switzerland is quite simply, to do that: to accelerate particles to speeds approximating that of light. And therein lies a potential key – or possibly gateway – to our future.
It sounds impossible but Professor Hawking contends that we really could go Back to the Future. DO we go back to the future or past? Future means something ahead of time, not back in time.
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