Lisa Randall interview

Poised on the Edge: An interview with Lisa Randall


New Humanist March-April 2012 issue


‘There is no question that there is an unseen world,’ Woody Allen once said. ‘The problem is how far is it from mid-town and how late is it open’. The notion of parallel realities has been a staple of science fiction ever since 1923 when H.G. Wells wrote Men Like Gods, in which there exists an alternative world with ‘no parliament, no politics, no private wealth, no business competition, no police, no prison’. The Utopians who inhibit this world had shared our past until history inexplicably branched. Yet by the late 1950s science caught up when Hugh Everett III, a graduate student at Princeton, showed that theoretically one could treat each and every possible outcome of a quantum experiment, such as measuring the position of a particle like an electron, as actually existing in an alternative parallel reality. He believed that his theory was the simplest interpretation of quantum mechanics, but accepting it was ‘a matter of taste’. At the time no one took his idea seriously. But as physics moves on, tastes change. 

‘I think multiple universes probably exist, but it's very unlikely we'll know about most of them,’ says Lisa Randall as we chat over coffee during a visit to London to promote her latest book, Knocking on Heaven’s Door.  The 49 year-old Harvard professor of theoretical physics leaves the door open to the possibility that there might be others that we can somehow glimpse. ‘The exception,’ she says ‘would be universes that affect properties of our own’. 


It’s an idea that Randall expands upon in her book, as she tries to portray what is happening today in particle physics and cosmology in terms of both experiments and theory.  For particle physicists and even cosmologists this is the era of the Large Hadron Collider, the gigantic particle accelerator under the Franco-Swiss border near Geneva that is smashing together protons at unprecedented energies in an attempt to recreate the conditions of the very early universe to test our understanding of the nature of matter and forces. ‘I wanted to convey the excitement and implications of the research taking place there,’ says Randall, ‘so when discoveries are made, anyone interested can understand what was found and what it could mean.’ And what it could mean is nothing short of mind bending. 

Theoretical physics at the cutting-edge is an exotic discipline and not much is more exotic than the notion of extra spatial dimensions in addition to the three that we are all used to. These extra dimensions could be flat, like three dimensions of our everyday existence. ‘Or they could be warped,’ says Randall ‘like reflections in a fun-house mirror’. They might be unimaginably small or infinite in size. ‘An infinite extra dimension might sound incredible,’ concedes Randall ‘yet an unseen infinite dimension and parallel universes within it are some of the possibilities for what might exist in our cosmos’.

It was in the 1980s that superstring theory emerged as the leading candidate for the ‘theory of everything’. Superstring theory says what we detect in our experiments as particles are not really particles at all but manifestations of the ‘vibrations’ of one-dimensional objects called ‘strings’. Superstrings vibrate in ten dimensions but we don’t notice these extra dimensions because they are curled up into a space that is infinitesimally small. ‘Since we don’t see them,’ explains Randall, ‘these new dimensions of space must be hidden.’ We would not notice a curled-up dimension ‘just like a tight-rope walker would view his path as one-dimensional, but a tiny ant on the wire might experience two’.

Physicists had known for years that extra dimensions could be rolled up, but it was only in 1999 that Randall and her former student Raman Sundrum discovered another reason that extra dimensions might be hidden. ‘Einstein's theory of relativity tells us that energy and matter curve space and time. We found that spacetime with extra dimensions could be so warped that even an infinite extra dimension could exist but escape detection.’ The Randall-Sundrum theory mimicked three dimensions so uncannily that evidence that supports three dimensions of space can also be regarded as supporting the idea of such warped extra-dimensional universes.

Not long afterwards Randall and another colleague discovered an even more startling theoretical possibility - the universe can have three spatial dimensions in some regions but have more or less in others. If Randall is right then we might find ourselves living in an isolated region with three spatial dimensions inside a universe with many more. Randall’s two papers soon became among the most cited of recent times.

However theoretically sound and mind blowing the idea might be, the question remains: is there any compelling reason to take extra spatial dimensions seriously? Randall argues there is, for ‘they may help solve some outstanding problems that have no convincing solutions without them.’

Why, for example, is gravity is so weak compared to the other known fundamental forces? ‘Gravity might not appear to be all that weak when you're hiking up a mountain,’ says Randall ‘but bear in mind that the gravitational force of the entire Earth is acting on you.’ However, throw in an additional warped dimension and in this new five dimensional spacetime gravity is strong in one region of a fourth dimension of space but very weak everywhere else. In this universal architecture it’s natural for gravity to be weak in our vicinity.

Randall enjoyed maths at high school in New York but chose to study physics because ‘I wanted something that could connect to the real world.’ After getting her PhD from Harvard in 1987 she returned in 2001 as its first female tenured professor of theoretical physics. ‘I do what I do’, she replies with good grace when I ask if she’s a role model for other women contemplating a life in science. ‘One of the nice side benefits is that I can potentially inspire other women, and men, and defy stereotypes.’ It was an unfair question, but it’s one that Randall doesn’t often escape especially after comparisons to Jodie Foster’s character in the film Contact (there is, it must be said, a slight resemblance).

‘Often people don’t really understand what science is and what we can expect it to tell us,’ says Randall. The book was an attempt to correct some of the misconceptions and that ‘we shouldn’t be afraid to ask big questions or to consider grand concepts’. A few days before we meet Randall appeared on Radio 4’s Start the Week to discuss her book and found herself sharing a studio with Richard Dawkins and Chief Rabbi Jonathan Sacks. ‘Finding the word “atheist” odd’, Randall says she would categorize myself as a ‘nonbeliever’.

‘Religion puts things together to see what they mean, science takes them apart,’ said Sacks during the programme. I remind Randall that at one point in the discussion she had responded by saying that it wasn’t science versus religion, but the rational versus the irrational.  ‘It's odd how often scientists get asked about religion because they really are such different enterprises. I do think however that it helps to precisely pinpoint the differences so we can have sensible conversation.’

‘The answer,’ believes Randall, ‘has to do with understanding that contradictions arise when we treat religion as something other than a social or psychological enterprise. When we believe an entity or spirit literally affects the world, or our choices today, this goes against the material mechanist view of science. That is why when the Chief Rabbi said that God is a gardener, who sets everything in motion, I asked whether he thought God keeps gardening. We don't know what happens in the beginning. Scientists won't choose a deistic interpretation but we can't show a contradiction either. But in later times or today, that would run counter to what science shows, unless we believe God just acts according to the rules of science in which case the role is rather unclear.’

Not one to shy away from the big questions, one of the things Randall is currently attempting to explain the amount of dark matter in the universe. With the biggest and most exciting experiments in particle physics and cosmology under way, what they reveal could provide clues that may ultimately change our view of the fundamental constituents of matter, and even of space itself. ‘We are,’ Randall believes, ‘poised on the edge of discovery’. 

Solvay 1911

The Witches Sabbath 

Nature.com, 21 November 2011

The First Solvay Congress, Brussels, October 1911. Left-to right standing – Robert Goldschmidt, Max Planck, Heinrich Rubens, Arnold Sommerfeld, Frederick Lindemann, Maurice de Broglie, Martin Knudsen, Fritz Hasenöhrl, Georges Hostelet, Edouard Herzen, James Hopwood Jeans, Ernest Rutherford, Heike Kamerlingh Onnes, Albert Einstein, Paul Langevin. Seated – Walther Nernst, Marcel Brillouin, Ernest Solvay, Hendrik Lorentz, Emil Warburg, Jean-Baptiste Perrin (reading), Wilhelm Wien (upright), Marie Curie, Henri Poincaré.


In June 1911 Albert Einstein was a professor of physics in Prague when he received a letter and an invitation from a wealthy Belgium industrialist. Ernst Solvay, who had made a substantial fortune by revolutionizing the manufacture of sodium carbonate, offered to pay him one thousand francs if he agreed to attend a ‘Scientific Congress’ to be held in Brussels from 29 October to 4 November. He would be one of a select group of twenty-two physicists from Holland, France, England, Germany, Austria, and Denmark being convened to discuss ‘current questions concerning the molecular and kinetic theories’. Max Planck, Ernest Rutherford, Henri Poincare, Hendrik Lorentz and Marie Curie were among those invited. It was the first international meeting devoted to a specific agenda in contemporary physics: the quantum.

Planck and Einstein were among the eight asked to prepare reports on a particular topic. To be written in French, German, or English they were to be sent out to the participants before the meeting and serve as the starting point for discussion during the planned sessions. Planck would discuss his blackbody radiation theory, while Einstein had been assigned his quantum theory of specific heat. Accorded the honour of giving the final talk, there was no room on the proposed agenda for a discussion of his light-quanta – better known these days as photons.

‘I find the whole undertaking extremely attractive,’ Einstein wrote to Walter Nernst, ‘and there is little doubt in my mind that you are its heart and soul.’ Nernst with his love of motorcars was more flamboyant than the staid Planck, but was just as highly respected – in 1920 he was awarded the Nobel Prize for chemistry for what became known as the third law of thermodynamics. A decade earlier, in 1910 he was convinced that the time was ripe to launch a cooperative effort to try and get to grips with the quantum he saw as nothing more than a ‘rule with most curious, indeed grotesque properties’. Nernst put the idea to Planck who replied that such ‘a conference will be more successful if you wait until more factual material is available’. Planck argued that ‘a conscious need for reform, which would motivate’ scientists to attend the congress was shared by ‘hardly half of the participants’ envisaged by Nernst. Planck was sceptical that the ‘older’ generation would attend or would ‘ever be enthusiastic’. He advised: ‘Let one or even better two years pass by, and then it will be evident that the gap in theory which now starts to split open will widen more and more, and eventually those still remote will be sucked into it. I do not believe that one can hasten such processes significantly, the thing must and will take its course; and if you then initiate such a conference, a hundred times more eyes will be turned to it and, more importantly, it will take place, which I doubt for the present.’

Undeterred by Planck’s response, Nernst convinced Solvay to finance the conference. Interested in physics, and hoping to address the delegates about his own ideas on matter and energy, Solvay spared no expense as he booked the Hotel Metropole. In its luxurious surrounding, with all their needs catered for, Einstein and colleagues spent five days talking about the quantum and, as Lorentz said in his opening remarks, the reasons why the ‘old theories do not have the power to penetrate the darkness that surrounds us on all sides’. However, he continued, that the ‘beautiful hypothesis of the energy elements, which was first formulated by Planck and then extended to many domains by Einstein, Nernst, and others’ had opened unexpected perspectives, and ‘even those who regard it with a certain misgiving must recognize its importance and fruitfulness.’

‘We all agree that the so-called quantum theory of today, although a useful device, is not a theory in the usual sense of the word, in any case not a theory that can be developed coherently at present,’ said Einstein. ‘On the other hand, it has been shown that classical mechanics…cannot be considered a generally useful scheme for the theoretical representation of all physical phenomena.’ Whatever slim hopes he abhorred for progress at what he called ‘the Witches’ Sabbath’, Einstein returned to Prague disappointed at having learnt nothing new. ‘The h-disease looks ever more hopeless,’ he wrote to Lorentz after the conference.

Nevertheless, Einstein had enjoyed getting to know some of the other ‘witches’. Marie Curie, whom he found to be ‘unpretentious’, appreciated ‘the clearness of his mind, the shrewdness with which he marshalled his facts and the depth of his knowledge’. During the congress it was announced that she had been awarded the Nobel Prize for chemistry. She had become the first scientist to win two, having already won the Physics prize in 1903. It was a tremendous achievement that was overshadowed by the scandal that broke around her during the congress. The French press had learned that she was having an affair with a married French physicist. Paul Langevin was another delegate at the congress and the papers were full of stories that the pair had eloped. Einstein, who had seen no signs of a special relationship between the two, dismissed the newspaper reports as rubbish. Despite her ‘sparkling intelligence’, he thought Curie was ‘not attractive enough to represent a danger to anyone’.

The Solvay Congress was the end of the beginning for the quantum. It dawned on physicists that it was here to stay and they were still struggling to learn how to live with it. When the proceedings of the conference were published it brought to the attention of others, not yet aware or engaged in the struggle, what an immense challenge it was to successfully do so. The quantum would be the focus of attention at the fifth Solvay conference in 1927. What happened in the intervening years is, as they say, history.

Robin Ince: The Science of Comedy

You don’t have to leave your brain at the door when going to a gig. I met up with the comedian who is taking Brian Cox and other scientists on tour.

Daily Telegraph, 30 April 2011

The “free visitor destination for the incurably curious”, otherwise known as the Wellcome Collection, opposite London’s Euston station, seemed an apt place to meet Robin Ince, comedian and co-presenter of Radio 4’s science-meets-humour chat show The Infinite Monkey Cage.

“There are a lot of intelligent, well-read comedians out there who are interested in science and who want to share their passions,” says Ince, who has done more than anyone to help them do just that. He is the brains behind Nine Lessons and Carols for Godless People, a variety show that celebrates science while giving the audience a healthy dose of humour and music.

Each Christmas since 2008 the shows have played to packed houses of non-religious people grabbing the opportunity to laugh out loud at the likes of comedian and trained physicist Dara O’Brien and being entertained by bite-sized lectures from scientists like the evolutionary biologist Richard Dawkins. “If the Royal Variety Show was put in a matter transportation machine with the Royal Institution Christmas Lectures,” says Ince, “this is what you’d get.” It’s what he calls “reading-list comedy”, because it’s all about ideas that leave the audience wanting more – and a bibliography.



Ince is about to give them more with his new tour, Uncaged Monkeys: A Night of Science and Wonder, opening in Oxford tomorrow and ending with two nights at London’s Hammersmith Apollo on May 16 and 17.

Ince’s fellow “monkeys” will be Brian Cox, recently on our screens presenting Wonders of the Universe; Ben Goldacre, psychiatrist and slayer of bad science; and Simon Singh, the best-selling science writer and celebrated debunker of the claims of alternative medicine. With their guests the quartet will be tackling everything from the Big Bang to bonobo apes and anything else they can cram into two hours.

Once again the driving force, Ince describes himself as “the idiot who will guide the audience”. Though he loved science as a child, he explains that he lost interest in it around the age of 13, “when science seemed to become facts and dull experiments with apparently no link to the world”.There was, he regrets, “no sense that the periodic table is really the ingredients list of the universe so far”.

It was only in his mid twenties that the popular books of Nobel Prize-winning, bongo-drum-playing physicist Richard Feynman rekindled his curiosity for all things scientific. “Taking a tour about science to theatres that seat up to 3,000 people is a project I’ve wanted to do for a long time,” admits Ince. The fact that he can do so may in part be down to an English-born, Canadian journalist and writer living in New York, one Malcolm Gladwell.

In November 2008, Gladwell’s two performances at the Lyceum, one of the largest theatres in London’s West End, were quickly sold out. A staffer at the New Yorker magazine, Gladwell is often described as one of the most brilliant and influential writers of his generation. His bestselling books, such The Tipping Point and Blink, identify and explore social trends and behaviour in novel ways. After his gigs in London he returned to Britain the following year to play four dates at venues that you’d normally associate with hip indie bands. Gladwell, with his afro and charisma, made ideas sexy, very much as Brian Cox is doing today.

Ince and Cox’s fellow uncaged monkey Simon Singh identifies three distinct types of event that are taking place: listening to scientists (lectures), discussing with scientists and celebrating science. “People have always gone to science lectures,” he says, “but the discussion and celebration of science in pubs and theatres is new.” He recently introduced a lecture by American physicist Brian Green to an audience of 900 at the Southbank.He admits that big events at big venues, like the Uncaged Monkeys or a lecture by a world-famous scientist, might not be “everybody’s cup of tea”.

For those who prefer things on a smaller scale, there is an ever-growing number of events like The Bright Club, a monthly variety night founded in 2009 by comedy promoter Miriam Miller and Steve Cross, University College London’s head of public engagement, as an arena for the staff and students from UCL to break free from the desks and labs and perform routines based on their research.

“Physically going out to these events involves a different level of engagement, than, say, watching Horizon at home, because you form part of the evening as an audience member,” says Miller. “You can go with friends and discuss the issues raised in the break or on the bus home, and at some of these events you can even interact with the people presenting information to you.” She believes that we have all the information in the world at our fingertips but that we don’t necessarily spend time discussing it with other people. She also believes that this social aspect is an important one: people who are interested in intelligent things usually don’t get to enjoy them together.

“Traditionally they’d watch TV or read books, both of which are pretty solitary,” argues Cross. “Other than that there are public lectures, which can be great, but most people just aren’t used to being lectured at for an hour.”

It seems more of us are prepared to let loose our inner geek, even if it’s just for the odd night. And it’s something that excites Ince because, “when you go to a well-run science gig, you don’t just come out saying 'That was fun’, you leave with your mind reeling with ideas that haunt and intrigue you”. We are not yet a nation of science-loving geeks, but as Ince says: “People now aren’t afraid to admit they like science. How can someone wilting under a stack of celebrity swimsuit mags belittle someone looking up at the stars?”

The Meeting of Minds

The Meeting of Minds
Nature.com, 23 March 2011

I first saw the photograph of those gathered at the fifth Solvay conference, which was held in Brussels from 24 to 29 October 1927, in a biography of Albert Einstein. This was in 1979, when I was just 16. I wondered what brought these people together, and soon learned that the picture included most of the key players involved in the discovery of the quantum, and the subsequent development of quantum physics. With 17 of the 29 invited eventually earning a Nobel Prize, the conference was one of the most spectacular meetings of minds ever held.


When I was 18, I was given a print of the above photograph as a present. Many years later I began to think about it as a possible starting point for a book about the quantum. In the photograph there are nine seated in the front row. Eight men, and one woman; six have Nobel Prizes in either physics or chemistry. The woman has two, one for physics, awarded in 1903, and another for chemistry, awarded in 1911. It could only be Marie Curie. In the centre, the place of honour, sits Albert Einstein. Looking straight ahead, gripping the chair with his right hand, he seems ill at ease. Is it the winged collar and tie that are causing him discomfort, or is it what he has heard during the preceding week? At the end of the second row, on the right, is Niels Bohr, looking relaxed with a half-whimsical smile. It had been a good conference for him. Nevertheless, Bohr would be returning to Denmark disappointed that he had failed to convince Einstein to adopt his Copenhagen interpretation of what quantum mechanics revealed about the nature of reality.

Instead of yielding, Einstein had spent the week attempting to show that quantum mechanics was inconsistent, that Bohr's 'Copenhagen interpretation' was flawed. Einstein said years later that:

This theory reminds me a little of the system of delusions of an exceedingly intelligent paranoic, concocted of incoherent elements of thoughts.

It was Max Planck, sitting on Marie Curie's right, holding his hat and cigar, who discovered the quantum. In 1900 he was forced to accept that the energy of light, and all other forms of electromagnetic radiation, could only be emitted or absorbed by matter in bits, bundled up in various sizes. 'Quantum' was the name Planck gave to an individual packet of energy, with 'quanta' being the plural. The quantum of energy was a radical break with the long-established idea that energy was emitted or absorbed continuously, like water flowing from a tap. In the everyday world of the macroscopic, where the physics of Newton ruled supreme, water could drip from a tap, but energy was not exchanged in droplets of varying size. However, the atomic and subatomic level of reality was the domain of the quantum.

Bohr discovered that the energy of an electron inside an atom was 'quantised'; it could possess only certain amounts of energy and not others. The same was true of other physical properties, as the microscopic realm was found to be lumpy and discontinuous. Not some shrunken version of the large-scale world that we humans inhabit, where physical properties vary smoothly and continuously, where going from A to C means passing through B. Quantum physics, however, revealed that an electron in an atom can be in one place, and then, as if by magic, reappear in another without ever being anywhere in between, by emitting or absorbing a quantum of energy.

By the early 1920s, it had long been apparent that the advance of quantum physics on an ad hoc, piecemeal basis, had left it without solid foundations or a logical structure. Out of this state of confusion and crisis emerged a bold new theory; known as quantum mechanics, with Werner Heisenberg and Erwin Schrödinger, third and sixth from the right in the back row, leading the way. In 1927 Heisenberg made a discovery. It was so at odds with common sense that he initially struggled to grasp its significance. The uncertainty principle said that if you want to know the exact velocity of a particle, then you cannot know its exact location, and vice versa.

Bohr believed he knew how to interpret the equations of quantum mechanics; what the theory was saying about the nature of reality. Questions about cause and effect, or whether the moon exists when no one is looking at it, had been the preserve of philosophers since the time of Plato and Aristotle. However, after the emergence of quantum mechanics they were being discussed by the twentieth century's greatest physicists.

The debate that began between Einstein and Bohr at the Solvay conference in 1927, raised issues that continue to preoccupy many physicists and philosophers to this day; what is the nature of reality, and what kind of description of reality should be regarded as meaningful? 'No more profound intellectual debate has ever been conducted', claimed the scientist and novelist CP Snow. 'It is a pity that the debate, because of its nature, can't be common currency.'

When Einstein and Bohr first met in Berlin in 1920, each found an intellectual sparring partner who would, without bitterness or rancour, push and prod the other into refining and sharpening his thinking about the quantum. 'It was a heroic time,' recalled Robert Oppenheimer, who was a student in the 1920s. 'It was a period of patient work in the laboratory, of crucial experiments and daring action, of many false starts and many untenable conjectures. It was a time of earnest correspondence and hurried conferences, of debate, criticism and brilliant mathematical improvisation. For those who participated it was a time of creation.'

Planck, Einstein, Bohr, Heisenberg, Schrodinger, Born, Pauli, De Broglie, Dirac, the leading lights of the quantum revolution, are all there in that picture.

The man who went nuclear

The Man Who Went Nuclear: How Ernest Rutherford Ushered in the Atomic Age


Independent, 3 March 2011

Did the nuclear age begin in 1942, when Chicago Pile-1, a reactor built in a squash court, went "critical" by achieving a self-sustaining chain reaction? Or was it on 16 July 1945 in the Jemez mountains in New Mexico, when "The Gadget", the first atomic bomb, was successfully tested and Robert Oppenheimer quoted the Bhagavad Gita? Maybe it was June 1954, when the Russian Obninsk nuclear station first generated electricity for the grid.

In reality, it was during a meeting of the Manchester Literary and Philosophical Society that the nuclear age was announced, on Tuesday, 7 March 1911, by Professor Ernest Rutherford, the 39-year-old head of physics at Manchester University. Rutherford was born in 1871, in Spring Grove, New Zealand. Descended from Scottish emigrants, it was from this scattered rural community on the north coast of the South Island that Rutherford's aptitude for science and maths led in 1895 to a coveted place at Cambridge. There, under the direction of JJ Thomson, Rutherford established a reputation as a fine experimentalist with a study of X-rays.

Though surrounded at Cambridge by all the excitement generated by Thomson's discovery of the electron in 1897, Rutherford opted to investigate radioactivity and soon found that there were two distinct types of radiation emitted from uranium, which he called alpha and beta, before a third was discovered, called gamma rays.

Aged just 27, in 1898, he was appointed professor of physics at McGill University in Montreal, Canada. Among his successes over the next nine years the most important was the discovery, with his collaborator Frederick Soddy, that radioactivity was the transformation of one element into another due to the emission of an alpha or beta particle. Rutherford regarded "all science as either physics or stamp collecting" but saw the funny side when he received the 1908 Nobel prize for chemistry for this seminal work. By then he was in Manchester.

"Youthful, energetic, boisterous, he suggested anything but the scientist," was how Chaim Weizmann, then a chemist but later the first president of Israel, remembered Rutherford in Manchester. "He talked readily and vigorously on any subject under the sun, often without knowing anything about it. Going down to the refectory for lunch, I would hear the loud, friendly voice rolling up the corridor."

At the time Rutherford was busy using the alpha particle to probe and unlock the secrets of the atom. But what exactly is an alpha particle? It was a question that Rutherford and his German colleague Hans Geiger answered. It was a helium ion; that is, a helium atom that had been stripped of its two electrons. Rutherford had noticed, while still in Montreal, that some alpha particles passing through thin sheets of metal were slightly deflected, causing fuzziness on a photographic plate. It was something he asked Geiger to investigate.

As instructed by Rutherford he fired beams of alpha particles at some gold foil and by the tiny flashes of light when they struck a zinc sulphide screen discovered that a few "were deflected through quite an appreciable angle". Soon afterwards Rutherford assigned a research project to a promising undergraduate called Ernest Marsden: "Why not let him see if any alpha particles can be scattered through a large angle?" Marsden found some alpha particles bouncing straight back after hitting the gold foil and Rutherford was shocked: "It was almost as incredible as if you had fired a 15-inch shell at a piece of tissue paper and it came back and hit you."

Marsden and Geiger made comparative measurements using different metals and they discovered exactly they same large angle scattering. In June 1909 they published their extraordinary results, but with Rutherford unable to offer any kind of explanation they attracted little interest.

After decades of intense arguments, by 1910 the reality of atoms was established beyond reasonable doubt. The most widely-accepted atomic model was Thomson's so-called "plum pudding". Its ingredients consisted of a ball of diffuse "positive electricity" in which negatively charged electrons were embedded like plums in a pudding. But Rutherford knew that the atom of his old mentor couldn't explain alpha particle scattering. The probability that the accumulated effect of a number of tiny ricochets off electrons in Thomson's atom resulted in even one alpha particle being scattered backwards was almost zero. By December 1910, Rutherford believed that given the mass and energy of an alpha particle the large deflections must be the result of a single collision with an atom. It led him "to devise an atom superior to J.J's" he said at time.

Rutherford's atom consisted of a tiny central core containing virtually all the atomic mass, which he later called the nucleus, but it occupied only a minute volume "like a fly in a cathedral".Most alpha particles would pass straight through Rutherford's atom in any "collision", since they were too far from the tiny nucleus at its heart to suffer any deflection. But if an alpha particle approached the nucleus head-on, the repulsive force between the two would cause it to recoil straight back like a ball bouncing off a brick wall. Rutherford said that such direct hits were "like trying to shoot a gnat in the Albert Hall at night". Rutherford's model allowed him to make definite predictions using a simple formula he had derived about the fraction of scattered alpha particles to be found at any angle of deflection.

Experimental checks performed by Geiger and Marsden confirmed the predictions, but few physicists beyond Manchester gave any serious attention to the nuclear atom. Although Rutherford did not explicitly suggest a planetary model of the atom, there were those who knew that's exactly what it was. For most that settled the matter, Rutherford's atom was fatally flawed. A model of the atom with electrons moving around the nucleus, like planets orbiting the sun, would collapse. Any object moving in a circle undergoes acceleration, if it happens to be a charged particle, like an electron, as it accelerates it continuously losses energy in the form of radiation. An electron in orbit around the nucleus would spiral into it. Rutherford's atom was unstable and the existence of the material world was compelling evidence against it. Enter Niels Bohr.

Arriving in Manchester in March 1912 to learn about radioactivity, it wasn't before long the 27-year-old Dane began thinking about how to prevent Rutherford's nuclear atom from collapsing. His solution employed the quantum – the idea that energy comes in packets. Bohr argued that electrons inside an atom could only move in certain orbits in which they did not radiate energy and therefore couldn't spiral into the nucleus. Bohr said that each orbit had a certain energy associated with it, so all the allowed orbits were in effect a series of energy levels, like the rungs of a ladder. For an electron to move between levels, the famous quantum leap, required it to absorb or emit a quantum of energy that was equivalent to the difference in energy between the two levels.

"It is difficult to overestimate the scientific importance of the discovery of the nucleus," says Sean Freeman, professor of nuclear physics at Manchester University. "Rutherford's insight, imagination and attention to detail enabled him to make revolutionary discoveries using rather rudimentary technology by modern standards. He was a true pioneer."

One of his most important achievements was made in his spare time while Rutherford was developing methods for detecting submarines during the First World War – he split the atom. Arriving late for a committee meeting one day, Rutherford didn't apologise, but announced: "I have been engaged in experiments which suggest that the atom can be artificially disintegrated. If it is true, it is of far greater importance than a war!" It was 1919 before he published the results that showed the nucleus contained positively charged particles he called protons by knocking them out of nitrogen nuclei using alpha particles – thereby effectively splitting the nucleus and hence the atom. It was the last work he did at Manchester before moving to Cambridge to take over from Thomson as head of the Cavendish Laboratory.

It was there that in 1932 his colleagues James Cockcroft and Ernest Walton "split the atom" using the world's first particle accelerator. Also at the Cavendish, James Chadwick used Rutherford's suggestion that there was probably another constituent to heavier nuclei to discover the neutron. The particle plays the central role in establishing a nuclear chain reaction. The three men were among the 11 former students and colleagues of Rutherford who would win the Nobel prize.

Another of those 11 was Niels Bohr, who said that Rutherford never spoke more angrily to him than he did one evening at a Royal Society dinner. He had overheard Bohr refer to him by his title (Rutherford was awarded a peerage in 1931) and angrily asked the Dane loudly: "Do you Lord me?" Rutherford never cared for the honours and was indifferent to academic or social standing. What mattered most to him were the results of experiments. "I was brought up to look at the atom as a nice hard fellow, red or grey in colour, according to taste," he once said. It was a model he replaced with an atom that began the nuclear age.

Culture Under The Microscope

Culture Under The Microscope
The Visceral Exhibition @ The Science Gallery, Dublin.

Independent, 10 February 2011



What is Life? It's a question that the quantum physicist Erwin Schrödinger tackled in three famous lectures given at Trinity College, Dublin. The first, on 5 February 1943, was heard by an audience that included the entire Irish cabinet led by Éamon de Valera.

Schrödinger is remembered today for making vivid the weirdness of the quantum world with his famous cat-in-the-box thought experiment. Schrödinger's cat is neither dead nor alive but exists in a superposition of states until we open it and look. Yet when his Trinity College lectures were published they became influential in persuading many young physicists that Schrödinger's methods might solve some of the problems in the developing field of molecular biology. James Watson and Francis Crick cited the book as a key inspiration for the research that led them to the discovery of the double-helix structure of DNA.

"Schrödinger with his mythical 'semi-living' cat, could be described as a pioneer of BioArt," says Dr Michael John Gorman, the director of Dublin's Science Gallery, which is also located in Trinity College. His tongue is firmly in his cheek as he accompanies 40 people on the short walk from his gallery to the Schrödinger Theatre, to discuss what life is. This is one of the many activities surrounding the gallery's latest exhibition, Visceral: The Living Art Experiment.

"BioArt" was a term coined in 1997 as a number of artists abandoned paints and brush in favour of cells, fragments of DNA, proteins and living tissue. Visceral, a month-long exhibition uses new technologies, tissue and neural engineering to explore the question "what is life?" People may be put off by some of the 15 works, some of which use human tissue as book covers or retinal cells to project film. Gorman admits there is something a little queasy about creating artworks from living tissue. "The very idea of tissue-engineering becoming an art form makes us squirm," he says. However, Visceral is all about provoking the sort of instinctive gut reaction that Gorman hopes will gets visitors asking questions about the ethical implications of manipulating living material and what we mean by "living".

The exhibition's curator, Oron Catts, believes that the "logic that drives things like nanotechnology, synthetic biology and even things like neuroengineering needs to be scrutinised and explored by people other than just scientists and engineers". It was one of the reason that Catts helped to set up SymbioticA, an artistic lab dedicated to a hands-on engagement with the life sciences based at the University of Western Australia in Perth.

"Our interest is in life," says Catts, "not only art or science." Yet the exhibition demonstrates the depth of the potential of interactions between art and science. For Gorman, nothing illustrates this better than Silent Barrage, the largest work on show. The product of a collaboration between Neurotica, a group of five artists, and Dr Steve Potter of the Georgia Institute of Technology in Atlanta, its a cutting edge piece of neural engineering. It consists of an array of robotic poles hooked up to neurons from the brains of rats in Potter's lab.

The array responds to the way visitors move through it and sends signals back to the neurons. These neurons then fire, making the robotic poles shudder up and down. Depending on the amount of audience activity, the neurons can undergo what is called a "barrage" – when they start firing in a chaotic fashion. This is exactly what happens during an epileptic seizure. With epilepsy affecting over 450000 people in the UK alone, it is hoped by the scientists involved that the data collected might lead to a better understanding of the process by which cells are calmed and seizures mitigated. And its not the only exhibit that promises something scientifically tangible.

The battlefield of Kathy High's Blood Wars is a Petri dish with the combatants being the white blood cells drawn from two different people. After a few hours slugging it out, one set of platelets will have destroyed the other. The "winner" of each cellular battle goes on to fight another participant. The concept may sound sinister to some with concerns about eugenics, but it is in an ingenious attempt to engage in the age-old debates surrounding traits inherited through blood.

Catts says that cell lines create a form of immortality since they can live beyond the life of the donor. I'm reminded of the story told by Rebecca Skloot in her bestselling book, The Immortal Life of Henrietta Lacks. Known to scientists as HeLa, Lacks died in 1951 but her cancer cells were taken without her knowledge and became one of the most important tools in medicine. The Vision Splendid, a work by Alicia King consists of two sealed glass jars, connected by tubes that contain nutrients and cultured human tissue. The cells were those of an unknown African-American girl aged 13. You're left wondering who owns the stuff our bodies are made of. If that worries you, then Catts offers a way to ease your troubles.

The Semi-Living Worry Dolls by Catts and Ionat Zurr are a modern version of the famous Guatemalan worry dolls constructed out of degradable polymer on which cells are grown in micro-gravity conditions. You can whisper your troubles to them through a microphone as they eventually replace the polymer completely, transforming the piece from fabric to tissue.

With the Irish general election rescheduled for the closing date of Visceral on 25 February, there's a rumour going around that the Silent Barrage installation may be able to predict the outcome – if political candidates are willing to present themselves to the cultured rat neurons in person.

Did You See The Gorilla?

Tehelka, 6 November 2010
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