So You Want To Be A Time Traveler?

A special guest article by Mark Thompson, Astronomy Presenter on the BBC's "The One Show," Fellow of the Royal Astronomical Society and Chairman of the Norwich Astronomical Society.

In a very cosmopolitan way, I’m typing this article in a coffee shop in Liverpool Street Station, London. My thoughts are with the intricate nature of the Universe and the tiny steps we have made so far to conquer space travel. As a society, our technology still needs to develop significantly to truly master it, but will we ever take the next step and travel through time?

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Time travel is the stuff of science fiction but interestingly, there is nothing in our current laws of physics that says time travel is impossible. Even such lowly things as the cup in front of me have mastered time travel to a degree. Sitting there on the table, seemingly doing nothing yet it is actually moving through time, relentlessly, at a rate of one day per day.

OK, so this isn’t real time travel since everything on Earth is moving through time at this rate. The big question is can we change this rate of travel, or even reverse it and move backward in time? After all, Dr Who can do it.

Quickly back to basics then: What is time? Time is just another component of something we call "space-time" in much the same way that a head or a tail are two sides of the same coin; space and time are both parts of the fabric of space-time. Since the two are related, maybe the secret to time travel is in manipulating space itself or perhaps our interaction with it.

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One very simple way to move forward in time at a different rate is to travel really REALLY fast through space. It turns out that the faster you go, the slower time seems to move for you with respect to everyone else. This concept is known as "time dilation."

For example: If I run around this coffee shop at speeds close to the speed of light, by the time I sit down again, I will have aged less than those around me. In effect, I will have traveled into their future.

This has been shown by experimentation where an atomic clock was left on the surface of the Earth and another was taken up in a high speed aircraft. By the time the two clocks were back together again, the one in the aircraft had aged less than the other.

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What about traveling back in time then? That's the exciting bit after all. One of the most tantalizing possibilities again makes use of the effects of time dilation.

We have seen that the faster you go, the slower time seems to pass with respect to the outside world. If your speed finally reaches the speed of light (300,000 kilometers per second) then time actually stands still, exceed the speed of light and its thought that time will start to flow backward.

There you have it, the key to travel backward in time. If only it were that simple.

Unfortunately there is a fly in the ointment, an effect of Relativity is that the faster you go, the heavier you become and as you reach the speed of light, you become infinitely heavy! To accelerate something that is infinitely heavy requires an infinite amount of energy. Therein lies the problem.

There isn’t an infinite amount of energy in the Universe and if there was, it's a little selfish of you to use it all in your fanciful flight backward in time!

SLIDE SHOW: Top 5 Sci-Fi Time Travel Methods

There may however be an alternative. Einstein’s theory’s of relativity only precludes travel at the speed of light, he never said anything about travel faster than light. Of course it will still take an incredible amount of energy, but crucially not an infinite amount.

Now it turns out that a little technique called quantum tunneling is used by electrons orbiting around atoms to instantly move from point A to point B without passing through the space in between.

If we could utilize a similar process and "quantum tunnel" through the barrier of the speed of light, we might just be able to travel faster than light, but never actually have to travel at the speed of light to get there.

All that remains is to fly around at this speed as time for the rest of the Universe rolls backward, decelerate at the appropriate moment and hey presto, you’ve popped out in July 1973 and time for one of the greatest moments in history, my birth.

While this all seems a little far fetched, it's actually only technology stopping us from doing it. Much the same could be said for space travel at the turn of the century, it seemed unattainable to travel to the Moon but once the technology had evolved it became possible.

It's all just a matter of time before we master not just space travel in a big way but also to conquer one of the final challenges left to mankind, the ability to travel through time and I for one, think that one day, it will happen.