On November 23, 1963, a national institution was born in the United Kingdom thanks, perhaps somewhat surprisingly, to a Canadian at the BBC, named Sydney Newman. The TV-viewing public was introduced to a humanoid alien from the planet Gallifrey. A time lord—the Doctor.
Doctor Who! Quintessentially British, this show and its quirky hero are celebrating their 50th anniversary this year (a sixteen-year gap aside). I remember as a young child watching from behind the sofa as enemy extraterrestrial races, such as the Daleks (“Exterminate!”) and Cybermen, sent my imagination into overdrive. More recently, the Doctor's arch-enemies are the inanimate-only-when-you're-looking Weeping Angels. Don’t blink!
The Doctor has two hearts and a sonic screwdriver that does almost everything—except work on wood. He can regenerate when fatally injured, which rather nicely explains the eleven actors who have thus far portrayed him. As actor Matt Smith bows out in the 2013 Christmas Special, the eleventh Doctor will regenerate into the twelfth and be played by Peter Capaldi. If you haven’t already guessed it, I absolutely love this show!
The Doctor explores the universe at random, using his extensive knowledge of science, technology and history to avert whatever crisis he encounters. He travels through time and space in an internally humongous time machine known as the TARDIS (Time and Relative Dimension in Space). The TARDIS's chameleon circuit was broken after a visit to London in 1963, leaving it stuck in the shape of a blue, 1960s-style London police box.
In 2011, research suggested that thirty per cent of adults across the UK believed that time travel is actually possible and not just found in fictional films or television.
They're not entirely wrong. We all travel in time. In the last year, I have moved forward one year and so have you. Another way to think about it is that we travel in time at the rate of 1 hour per hour. But the billion-dollar question is—can we travel in time faster or slower than that? Or can we actually travel backward in time, going back, for example, 10 or 100 years per hour?
In 1905, the great scientist, Albert Einstein shook the foundations of physics with the introduction of his special relativity theory. The basis of the theory is that there's a speed limit of 299,792,458 metres per second for anything that travels through space and time. Light always travels the speed limit through empty space. You know this concept as the speed of light.
Einstein's theory implies that as an object gets closer to the speed of light, time slows down. According to the special relativity theory, if something could travel faster than the speed of light, it would be freed from the confines of time and possibly be able to time travel. So if you were to hop into your very own TARDIS and travel close to the speed of light, time will go more slowly for you than for the people you left behind. However, you won't notice this effect until you return to those stationary people. Basically, Einstein was saying that time changes with motion.
Currently, scientists believe the speed of light is the highest speed at which something can travel, meaning it would be impossible to travel back in time. Still, many scientists actually believe in the possibility of time travel. Whilst they may not see themselves visiting the Stone Age anytime soon, they maintain that travelling into the future would be less difficult than travelling into the past.
Einstein had another theory called general relativity, which predicts that time passes more slowly for objects in gravitational fields (like here on Earth) than for objects far from those fields. That would mean that there are all kinds of space and time distortions near black holes, where the gravitational field is very intense. Some scientists have suggested that black holes and other phenomena can help time travel into the future. With a better understanding of black holes and future advancements in technology, perhaps one day we could travel 10,000 years into the future and only age by one year during that journey.
You may think that this is all still in the realm of science fiction, yet time distortions, explained by Einstein’s two theories, are taken into account by scientists and engineers when they plan space missions. Despite these effects being incredibly small, fractions of a second matter in navigating a spacecraft throughout the solar system.