Nothing is Impossible
Time travel, telepathy, free energy… science-fiction pipe dreams, right? Not according to scientists who are stretching the laws of physics to the brink. Paul Parsons says to hell with the horizon.
That’ll never work. We’ve all heard it. A few of us have probably even said it. That disparaging adage was once uttered about endeavours that today have become almost routine – such as brain surgery, flight and sending people into space.
But human ingenuity and determination make a formidable combination. So much so, that we’ve almost made a habit of achieving the seemingly impossible.
And we’ve already got our teeth into the next wave of amazing scientific possibilities – breakthroughs-in-waiting like artificial intelligence, invisibility, telepathy and even time travel. According to scientists, there are monumental discoveries to be made that could see us holding conversations with machines, living forever, beaming about in Star Trek-style teleporters and extracting energy from empty space.
The only problem is cash. We know that when governments stump up the readies, results follow. America went from never having launched a human into space to landing one on the Moon in about eight years. But only after coughing up $25.4bn – nearly three per cent of the country’s 1969 GDP and around $150bn in today’s currency.
So, given the intent, the motivation and the money, what are the impossibilities that science could make possible over the years to come?
Just flip a switch and go anywhere – in an instant.
Will we ever be able to leave our cars at home once and for all, and teleport from A to B like Captain Kirk?
Various theoretical schemes have been suggested, and some even tested out experimentally, with scientists successfully beaming individual subatomic particles from one side of a lab to the other. But there’s a gaping chasm between sending subatomic particles and sending people.
In 2007, a team from the University of Queensland, Australia, proposed a new method of teleportation that could transmit thousands of particles of matter in one go –a big step in the right direction.
“We showed a scheme that was able to turn the whole quantum state from one system of matter into light, and then back again,” says team member Dr Joseph Hope.
“We feel our scheme is closer in spirit to the original fictional concept,” adds his colleague Dr Simon Haine.
Researchers at the Australian National University, in Canberra, plan to test the idea over the coming years. Though full-on teleportation of people is still a lifetime away.
The first time machine might already be with us…
Ronald Mallett was 10 years old when his father died of a massive heart attack, aged just 33. He was devastated. A year later he read The Time Machine by HG Wells, and resolved, there and then, to build a time travel device so he could go back and prevent his father’s premature death.
That was over 50 years ago. Mallett is now Professor of Physics at the University of Connecticut, but his childhood ambition to travel into the past burns as bright as ever.
“Early on, I didn’t tell people what I was doing because I didn’t want it to affect my career – so I studied black holes as a cover story,” he says. “But, on the side, I was always trying to understand more about time and how you might go about building a time machine.”
Over the years, Mallett has perfected what he now believes is a valid design for his device. It works using circulating beams of light to drag space and time around into closed loops, like coffee stirred around in a mug. The idea is that as time spins in a closed loop, some of it has to whirl into the past.
Mallett is now working with an experimental physicist – Professor Chandra Roychoudhuri, also at the University of Connecticut – to test the design. They plan to use an elaborate set-up of lasers to create circulating loops of light, which they hope will be powerful enough to send subatomic particles briefly back through time. They propose to measure the effect by using particles that decay naturally over a well-defined timespan. For example, pion particles have a lifetime of just 26 billionths of a second. If these particles are made to travel back through time then their observed decay lifetime should get shorter. The researchers are now seeking funds for the work, which Mallet estimates will take around 10 years to complete.
Subatomic particles are one thing, but what about sending people back? “That would require international cooperation,” he says. “But I think if we were given unlimited funds we could see this machine in action within this century.”
Mallett’s story is currently being adapted for the screen by Spike Lee.
Fluent in over six million forms of communication… well, not quite
How soon will it be before machines can think on our level?
In 1950, British computing pioneer Alan Turing set out a way of gauging a machine’s intelligence by literally having a chat with it. The idea is that you hold a conversation with both the machine and a real person. You aren’t told which is which, and if you can’t figure it out from the conversation then the machine is considered to have demonstrated human intelligence. This has since become known as the ‘Turing test’.
In 1990, the annual Loebner Prize began, where computer scientists come together to apply the Turing test to their conversational software creations. Each year, the best of these ‘chatterbots’ receives a small cash prize, with $100,000 set aside for the first machine that is able to fool at least four of the contest’s 12 judges.
To date, nobody has scooped the big money yet. However, the 2008 winner, Elbot (www.elbot.com), developed by Hamburg-based programmer Fred Roberts, convinced three of the judges – just one shy of the main prize.
“I believe that the Turing test will be passed regularly by 2015,” says British programmer Rollo Carpenter, whose chatterbots won the Loebner Prize in 2005 and 2006. “We will genuinely be talking to machines, and think they understand.”
Will these machines really be intelligent? Probably not. “They will be imitating thought,” says Carpenter. “But can we really say where imitation ends and intelligence begins?”
Now you see it, but soon you won’t
It’s the ultimate in camouflage technology – an invisibility cloak that makes anything placed under it literally vanish from view. And it was recently demonstrated by researchers at the University of California, Berkeley.
The cloak, developed by UC Berkeley’s Professor Xiang Zhang and colleagues, consists of a piece of silicon that’s been engineered on tiny scales to give it some unusual optical properties. By perforating the silicon with a carefully designed pattern of holes – each just 110 nanometres in diameter, about one 10,000th of a millimetre – the team were able to reflect light in just the right way to conceal the bulge created by objects beneath it. The cloak can still be seen, but shining a beam of light on it produces a reflection identical to the reflection you would see from a flat surface.
For the time being Prof Zhang’s cloak only works in two dimensions, meaning that it can conceal objects placed on flat surfaces, but not something floating mid-air. “In this experiment, we have demonstrated a proof for the concept of optical cloaking that works well in two dimensions,” says Zhang. “Our next goal is to realise a cloak that works in all three dimensions.”
This will require developing a new cloak that can deflect light around a three dimensional object – rather like water flowing around a rock in a stream. Zhang’s colleague Dr Jensen Li, also at UC Berkeley, thinks this could happen very soon. “We expect invisibility to be demonstrated by coating a small object with a bulk, three-dimensional metamaterial, hopefully within a few years,” he says.
One day soon, we’ll all have voices in our heads
Imagine being able to communicate with anyone, simply by the power of thought. This is the promise of telepathy. But while many entertainers and self-proclaimed psychics claim telepathic abilities, there’s little evidence to support them. Now though, some technologists believe humans could become telepathic using artificial brain implants.
Dr Robert Freitas, Senior Research Fellow at the Institute of Molecular Manufacturing in California, imagines a swarm of microscopic nanorobots that could sit inside the human brain, monitoring neural activity. “10 billion two-micron-wide nanorobots – one to monitor each neuron – would add just 200mg to the brain’s overall weight, and add two Watts to its heat output,” says Dr Freitas. That’s small beer compared to the 1.4kg weight of an unmodified brain and the body’s 90W nominal rate of heat loss.
The nanobots then transmit their data as ultrasound to a hub, also within the skull, where any signals intended for transmission are converted to radio and beamed out. The reverse process allows signals to be received. Users would have to train themselves to use the technology, much like paraplegic patients who successfully use brain interface technology to control a computer.
Telepathy would then play out like a Skype call that exists only in your head. You’d select somebody to ‘call’ from a mental address book, and the technology would interpret your desire to speak with them. “As the nanorobots manipulate cochlear nerves directly, the recipient would experience a ‘voice inside their head’ that nobody else could hear,” says Dr Freitas. “Or a video signal could be retinally displayed in their field of view, like a heads-up display.”
He estimates that with suitable funding, so-called synthetic telepathy could be a reality within 40 years.
The idea of an invisible shield to protect a spacecraft from the dangers of life on the final frontier is a dream that’s been immortalised in science fiction. Now a team of scientists at the Rutherford Appleton Laboratory in Oxfordshire have figured out how it could be done.
Team leader Dr Ruth Bamford proposes to surround a spacecraft with a magnetic field that can bat away electrically charged proton particles from the Sun. These particles spew from the solar surface in outbursts that can occur as often as twice a day when the Sun is at its most active. And they pose a deadly threat to astronauts.
“If a solar proton storm were to pass through a spacecraft the astronauts would be unlikely to survive it with current technology,” she says. This is a real problem if, ultimately, we want to send humans to Mars and beyond – where the journey time is months or even years.
Dr Bamford’s deflector shield works by wrapping the spacecraft in a protective magnetic bubble, much like the magnetosphere that surrounds the Earth. This isn’t a new idea, but it was always believed to be impractical. “It was thought that the magnetic bubble surrounding a spacecraft had to be around 20km across, making the magnet on the spacecraft massive and requiring megawatts of power,” says Dr Bamford. “What we have now found, in theory, computer simulation and lab experiment, is that a magnetic bubble just 100m across would be sufficient to protect the spacecraft.” And the magnet required is small enough to fit inside an astronaut’s hand luggage.
All of the technology required to build Dr Bamford’s deflector shield exists today. “There is still much to be done before we’d risk a human life on it,” she says. “But we have the start of a solution.”
Are we about to make the jump to light-speed?
May 1994 saw Trekkies celebrating. Why? Because a young physicist called Dr Miguel Alcubierre at the University of Cardiff had published a serious outline for a warp drive – a spacecraft engine that could, in principle, be faster than light.
The idea centred on Einstein’s general theory of relativity, in which the structure of space can be manipulated according to the matter and energy it contains. Alcubierre showed that by surrounding a spacecraft with the right kind of matter it’s possible to shrink the space in front of it and expand the space behind it – sweeping the vessel along to its destination.
But the celebrations were short-lived. Alcubierre knew that his warp engine relied on a strange kind of matter with negative mass. And subsequent calculations suggested the amount needed was greater than the mass of the entire Universe.
Now, the Trekkies could be due another celebration. Two US researchers think this negative-mass material could be mined from hidden dimensions of space. The cosmos is already known to be filled with negative mass ‘dark energy’, which astronomical studies have shown is causing the expansion of the Universe to accelerate. Gerald Cleaver and Richard Obousy at Baylor University, Texas, say that dimensions beyond the three we know about could be huge stores of dark energy, which we can tap into.
They say that by altering the energy density in the three dimensions we can see, it’s possible to change the size of the higher dimensions. “By adjusting the size of the higher dimensions you could locally adjust the dark energy density and gain control over the expansion and contraction of space,” says Dr Obousy. He adds that the idea could be tested in large particle accelerators, such as the Large Hadron Collider at CERN.
Meet the nanobots that will leave the Energizer bunny standing.
Building a device that can conjure energy from thin air is a problem that’s taxed the great thinkers for centuries. But now a physicist in Germany has come up with a free-energy machine that actually works.
Dr Thorsten Emig’s idea is based on the so-called Casimir effect. Here, two parallel metal plates a tiny distance apart experience a force that pulls them together. That’s because empty space isn’t really empty; it’s a seething mass of subatomic particles zipping in and out of existence.
We can also think of these particles as waves. Outside the plates, waves of all wavelengths can exist. However, inside there can only be waves that fit between the plates (think of the waves on a string – you can’t have any with a half-wavelength longer than the string). Converting back to particle language, this means there are more particles jiggling about outside than inside, creating a net force that pushes the plates together.
Emig has designed a ‘Casimir ratchet’ that can extract useable motion from this effect. Substituting smooth plates for corrugated ones introduces a lateral force that makes the Casimir plates slip past one another. And by making the corrugations asymmetric, Dr Emig keeps this slipping motion in one direction so that it generates a turning force that can be harnessed. “A lateral Casimir force between a corrugated plate and a sphere has been measured already by a team at the University of California, Riverside,” says Emig.
He believes his Casimir ratchet could be used to power tiny nanorobots, which have a host of applications in medicine. Sadly, the same technology can’t yet be scaled up to power cars, factories or cities.
Live forever, but possibly in another universe…
Scientists have long sought the secret of living forever. Now, some believe they may have found it. And it’s got nothing to do with diet, exercise or miracle drugs. The key to eternal life may instead be buried deep in the laws of fundamental physics – quantum theory, to be precise.
In the quantum world of subatomic particles, nothing is certain. Everything happens at random, according to the probabilities that quantum theory predicts. Philosophers are still arguing about what these quantum probabilities really mean. But one increasingly popular school of thought is the so-called ‘many worlds interpretation’. This suggests the existence of a huge number of parallel universes. When quantum physics predicts that, say, an atom will decay with a probability of 50 per cent, it means that in half the universes the atom decays, while in the other half it remains intact. Probability no longer governs whether the atom decays or not (it does both, just in different universes). Instead, probability determines which universe you find yourself in.
Physicist Max Tegmark, of MIT, has devised an experiment that takes advantage of this. Tegmark imagines a rifle with an automatic mechanism to pull the trigger every second. The mechanism is linked to a quantum randomisation device that determines whether it will either fire a live round or click harmlessly with 50/50 probability.
“You start off just observing the rifle and you find it goes off randomly – click-click-bang-click-bang-bang, and so on,” he says. “After you’ve watched for a while you put your head in front of the barrel, and it just keeps going click-click-click-click…”
Amazingly, you never find yourself in a universe where you die. The reason is that all parallel universes are equally real. Copies of you exist in all of them – and, after the trigger is pulled, half of these copies are left alive. The other half simply cease to exist. Since there is no way for you to experience the copies of you that are dead, Tegmark says you must end up in one of the universes where you remain alive.
He envisages a number of twists on the idea. For example, you can imagine future technology that monitors the state of every DNA molecule in your body, and is then rigged to kill you the moment it detects a cancer-causing mutation. Because the mutation of a molecule is a quantum event, you’d therefore always find yourself in a universe where you never got cancer.
For the time being, Tegmark’s idea is just a mind-melting thought experiment – no-one’s actually tried it. Even Tegmark himself has no immediate plans to give it a go. “Though maybe if I found out when I’m 102 that I have a terminal illness then it might be interesting,” he says.
Dr Paul Parsons is a science writer and analyst based in Aylesbury, England. He is a lapsed cosmologist, a former managing editor of BBC Sky at Night magazine, and once spent a summer working in a toilet roll factory. His books include 'The Beginning and the End of Everything', 'The Science of Doctor Who' and, most recently, '10 Short Lessons in Space Travel'.