Tuesday, 17 April 2012

The Atheist's Guide to Reality

The Atheist's Guide to Reality: Enjoying Life Without Illusions by Alex Rosenberg

Independent, 18 April 2012

There are plenty of books that make the case for atheism, but Alex Rosenberg's The Atheist's Guide to Reality isn't one of them. The American philosopher maintains that religious belief is immune to rational objection. There's little point, argues Rosenberg, in preaching to the unconverted. His aim is to enlighten the converted by arguing for what an atheist should believe, since there's more to atheism than simply "there is no God". He begins by rebranding atheism as "scientism" so as to better describe what atheists "do believe". First, an atheist has to understand the science, then accept its "irrefutably correct answers to the persistent questions". What is the nature of reality? What physics says it is. What is the purpose of the universe? There is none. What is the meaning of life? Ditto.

Rosenberg's scientism is built on accepting well-established laws of physics as the basic description of reality. He argues that the physics tells us just about everything we need to know about how the universe works. We can extend this to chemistry and biology, and then, with an appeal to Darwinian processes, everything else. For Rosenberg, almost everything we think of as having inherent value or meaning, from morality to the idea of a self, does not. He wants us to let go of our many illusions, such as the concept of free will. Being "scientistic" means treating science as the "exclusive guide to reality" and accepting that it "enables atheism to answer life's universal and relentless questions".

Rosenberg argues that atheists are assailed on all sides by attempts to sow doubt about the completeness and credibility of science. Worse still, some of those questioning the reach of science are people with impeccable scientific qualifications. Rosenberg wants to clarify "what our attachment to science... really commits us to".
There's much that Rosenberg writes one can agree with; as for the rest, it's at least thought-provoking. If you can't swallow science's answers as interpreted by Rosenberg, he has one last piece of advice: "Take a Prozac or your favourite serotonin reuptake inhibitor, and keep taking them till they kick in."

Tuesday, 27 March 2012

How It Began

How It Began: A Time-Traveller's Guide to the Universe by Chris Impey

Wall Street Journal, 28 March 2012

'The theory is beautiful beyond comparison" is how Albert Einstein modestly described his theory of gravity, known as general relativity. He believed that "scarcely anyone who fully understands this theory can escape its magic." In the years since 1916, when he published a paper setting out the theory, few have disagreed, yet buried within his greatest achievement was also what Einstein considered "my greatest blunder."

The equations of general relativity can be solved in a number of different ways, with each solution representing a model of a possible universe. Like everyone else at the time, Einstein believed that the universe was eternal and unchanging, so he incorporated a mathematical term, the "cosmological constant," to ensure that that was exactly how it remained. This fixing of the equations was Einstein's great blunder, for he failed to grasp the full magic of his theory. It was left to others to take seriously the solutions that pointed to a universe that was not static but expanding.

In his previous book, "How it Ends" (2010), Chris Impey, a professor of astronomy at the University of Arizona in Tucson, outlined the ultimate fate of our expanding universe. It was a somber scenario in which galaxies sail apart at an ever-increasing rate as the stars within them fade to dark embers, with the structure of the universe eventually unraveling.

In his latest book he tackles the more difficult question of how the universe began. In clear, enthusiastic and occasionally lyrical prose, Mr. Impey takes the reader on a mind-blowing tour back through eons, stopping along the way to explain the formation of the solar system, the birth and death of stars, white dwarfs, supernovas, spiral galaxies, cosmic inflation, string theory, black holes and M-theory—an extension of string theory featuring 11 space-time dimensions that can be curled up into the four we're familiar with in 10500 (1 followed by 500 zeros) ways. Each such solution leads to another potential universe, but ours is the one that interests Mr. Impey.

 Georges Lemaître

It was the Russian mathematician Alexander Friedmann who, in 1922, first showed that general relativity predicted an expanding universe. But Mr. Impey rightly chooses to highlight the work of Georges Lemaître, a Belgian priest who was also a physicist. In 1927 Lemaître realized that "running the clock backwards" on an expanding universe led to one that was smaller, denser and hotter in the past. "The fireworks are over and just the smoke is left," he said of the quest to imagine the initial state of the universe. "Cosmology must try to picture the splendor of the fireworks." Lemaître eventually arrived at a model that he called the "primeval atom" and that we call the Big Bang.

When Lemaître discussed the idea with Einstein, he was unimpressed. "Your math is correct, but your physics is abominable," he told Lemaître. Yet six years later, in 1933, Einstein heard Lemaître lecture and afterward admitted it was "the most beautiful and satisfactory explanation of creation I've ever heard."

The reason Einstein changed his mind was that by the late 1920s the American astronomer Edwin Hubble had discovered two remarkable facts. The first was that what we had long assumed to be the universe was only our host galaxy, the Milky Way, which in turn was just one of many such "island universes." Second, Hubble found that light from these distant galaxies was stretched toward the red end of the visible spectrum. This so-called redshift is evidence that these galaxies are moving away from our own and that the universe, therefore, is expanding. This supported Lemaître's theory that if the expansion could be rewound, the universe would steadily contract and eventually reach what he called "a day without yesterday."

According to the Big Bang model that has grown from Lemaître's insight, the moment of instantaneous creation was 13.75 billion years ago and began with a singularity, a point of infinite mass and density where our present understanding of physics simply breaks down. Yet "the Big Bang is all around us," Mr. Impey notes, in the form of cosmic microwave background radiation, which suffuses the entire universe. Soon after it was discovered in 1964, scientists recognized this radiation as the echo of the Big Bang, an afterglow from the era when the universe was hotter and denser. "There are tens of thousands of microwaves from creation in every breath you take," Mr. Impey delights in revealing.

It had long been assumed that gravity would act as a brake on cosmic expansion, but astronomers were horrified to discover in the 1990s that the expansion is speeding up. "Dark energy" is the mysterious culprit, but the name is more of a sign of ignorance than a physical description of something that makes up approximately 73% of the mass-energy of the universe. If that wasn't surprising enough, an analysis of the motion of galaxies reveals that approximately 23% of the universe is made up of something dubbed "dark matter." This means we know nothing about roughly 96% of our universe.

The Big Bang model also says nothing about what banged, why it banged or what happened before it banged. So in the 1990s cosmologists began to take seriously the idea that our universe is but part of a "multiverse" of different universes, each with its own laws of physics. It's a step too far for Mr. Impey, who suggests that "with the multiverse we seem to have taken leave of our senses and entered into wild speculation." There are some excellent books on this new multiverse cosmology, such as John Barrow's "The Book of Universes" and Brian Greene's "Hidden Reality," but "How It Began" deserves to be a well-thumbed guidebook for—and in—this universe.

Monday, 26 March 2012

Turing's Cathedral

Turing's Cathedral:The origins of the Digital Universe by George Dyson
Daily Telegraph, 24 March 2012
"Princeton is a madhouse,” wrote Robert Oppenheimer in January 1935. Twelve years later, after directing the building of the atom bomb, he would return to the Institute for Advanced Study (IAS) to take charge of this “madhouse”.

One of the permanent residents was Einstein. Another of Oppenheimer’s new charges was a former colleague from the Manhattan Project who was now “thinking about something much more important than bombs”.

The Hungarian-born polymath John von Neumann would make seminal contributions to everything from quantum mechanics to game theory, and had turned his prodigious talent to “thinking about computers”.

On November 12 1945, he gathered together six people and started the IAS’s Electronic Computer Project to design and construct a programmable electronic digital computer. After five years the Mathematical and Numerical Integrator and Computer (Maniac) was fully functioning but it had only five kilobytes of storage, less memory than is used to display a single icon on your computer screen.

The rest may be history but it’s one George Dyson is uniquely qualified to capture in Turing’s Cathedral. The son of the distinguished physicist Freeman Dyson, he grew up in the environs of the IAS where his father has been a member since 1948. Dyson used his privileged position to gain access to people and to explore archives untouched for decades. The years of research and writing have enabled him to bring to life a myriad cast of extraordinary characters each of whom contributed to ushering in today’s digital age.

While our universe may have popped out of nothing due to what physicists describe as a quantum fluctuation, the origins of the digital universe of 0s and 1s required the US military’s desire to be armed with a hydrogen bomb at the beginning of the Cold War and it “had to be squeezed into existence” between simulations of nuclear explosions. Two real-world explosions in 1952 and 1954 confirmed the correctness of those calculations and the indispensable nature of a computer that could be reprogrammed to carry out different tasks, the theory behind which had first been worked out by the British mathematician Alan Turing.

Alan Turing
Despite its title, Turing doesn’t make his much anticipated entrance in Dyson’s book until chapter 13, when as a 24-year-old he boards a transatlantic liner bound for New York in September 1936. Turing was to spend the next two years in Princeton working on his PhD, but before leaving Britain he had already finished his seminal paper “On computable numbers”. It would, as Dyson points out, “lead the way from logic to machines” as Von Neumann’s team turned Turing’s theoretical ideas into Maniac. 

Turing may have been the intellectual visionary, but Dyson’s book is about Von Neumann, the chief architect who oversaw the construction of the hardware and software architecture that allowed sequences of code to be stored, recalled and executed. Yet Dyson acknowledges that Maniac was not the first operational stored-programme computer. That was the Small Scale Experimental Machine, developed in June 1948 at Manchester University where Turing was by then based having helped break the German navy’s Enigma code during the war as a leading member of Bletchley Park.

Turing and Von Neumann were chalk and cheese in everything except their shared interest in computers. Von Neumann always dressed in a suit and spoke with precision; Turing was unkempt and hesitated as if words could not keep up with his thoughts. Von Neumann had an eye for women; Turing’s homosexuality would lead to a conviction for gross indecency. Forced to undergo “therapy” with oestrogen injections, he committed suicide in 1954.

Faced with the tricky task of balancing technical details with keeping the narrative accessible for the non-computer buff, Dyson ends up probably not giving enough detail to satisfy the aficionado but too much for the lay reader. “Evolution in the digital universe now drives evolution in our universe,” he says, “rather than the other way around.”

Turing, Von Neumann and their colleagues may have let the genie out of the bottle, but Dyson has done the difficult job of reminding us of how much we owe them and how far we have come in such a short time.

Saturday, 17 March 2012

About Time

About Time: From Sun Dials to Quantum Clocks, how the Cosmos Shapes Our Lives by Adam Frank

Daily Telegraph, 17 March 2012

St Augustine, the fifth century theologian and Church father, famously discussed the nature of time in Book XI of his Confessions: ‘What is by now evident and clear is that neither future nor past exists, and it is inexact language to speak of three times – past, present, and future. Perhaps it would be exact to say: there are three times, a present of things past, a present of things present, a present of things to come.’ For centuries it was a description as good as any.

Today there are many books on the nature of time as we experience it and even more on cosmic time as revealed by science. Yet few attempt to recount the entwined narratives of cosmic history and human time as a unified whole. Adam Frank’s About Time does just that. An astrophysicist at the University of Rochester, he and many of his colleagues believe that ‘the Big Bang is all but dead’. 

Frank and the others do not doubt the scientific narrative of cosmic evolution over the last 13.7 billion years, only the ‘bang’ in Big Bang. The moment of creation with no before is being questioned because of the very precision of the science that gave the notion ‘a measure of reality in the first place’. ‘The roots of cosmology cannot be reworked without a new conception of time, including its origins and its physical nature,’ argues Frank in this excellent book.

Cultures have always needed a cosmology to understand their place in the framework of creation. Frank shows how, as our ideas about cosmology and cosmic time have changed, human time has also changed. Acknowledging that the broad sweep of history, science and time which follows focuses primarily on the cultural development associated with the West, for Frank the most potent and obvious example of the binding of human and cosmic time is the industrial revolution with its roots in the scientific discoveries of Newton and its radical reformation of everyday life.

The first intimation of the modern structured day was born in the medieval monasteries. From sunrise to sunrise, the monks followed the horae canonicae, the rounds of worship beginning from sunrise (matins) through midday (sext) and sunset (compline) and through the night to matins again. 

Yet the division of the day into 24 hours was an invented by Babylonian astronomers, but it did not gain widespread acceptance until the advent of mechanical clocks in the 14th century. No one knows who invented the clock and in particular its key component – the escapement, the notched metal rings that allow gravitational energy stored in a hanging weight to be regulated and regularly released.

Prague's famous town clock
By the end of the 15th century, the town clock was a matter of civic need and pride. Soon the ancients’ Earth-centre universe gave way to Copernicus’s sun-centred cosmos and then to Newton’s clockwork universe, with space and time as absolute, unchanging and eternal. 

Throughout 18th century the new universal laws of physics reworked human conceptions of the heavens and before long led to machines that paved the way to industrialisation. And today we describe times in digital format – for example, 1.17 p.m. ‘It’s a new time that we have created in our hyperdigital, telepresent, instant-messaged society,’ says Frank. 

After 50 years of trying, physicists still lack a theory of quantum gravity – ‘a theory of space and time on scales so small entire universes could be bound in an atom’. Consequently cosmology, and our understanding of time, remains incomplete and full of speculation. Is the universe one in a long line? Could there be many bangs going off all the time, creating simultaneously existing universes – a multiverse? These ideas might sound like science fiction but they are being seriously pursued by some theorists while others, reports Frank, hope for ‘something else, something better, something not yet imagined’.

Monday, 12 March 2012

A Universe From Nothing

A Universe from Nothing: Why There is Something Rather than Nothing, by Lawrence M. Krauss.

Financial Times, 10-11 March 2012

Why is there something rather than nothing? “While this is usually framed as a philosophical or religious question,” writes Lawrence Krauss in A Universe from Nothing, “it is first and foremost a question about the natural world, and so the appropriate place to try and resolve it, first and foremost, is with science.”

A leading physicist at Arizona State University, Krauss begins his entertaining and engaging introduction to cosmology by pointing out that when scientists ask “why?” they usually mean “how?” So for “Why is the Earth 93m miles from the Sun?” read “How is the Earth 93m miles from the Sun?” What we need to understand are the physical processes that led to the Earth ending up in its present position.

“Nothing expands the mind like the expanding universe,” says Richard Dawkins in an afterword to this book. It was the American astronomer Edwin Hubble who, in the 1920s, discovered the first evidence that we lived in an expanding universe. As Krauss makes clear, the weight of the accumulated observational data since points to a Big Bang some 13.75bn years ago.

There have been a number of fine cosmology books published recently, but few have gone so far, and none so eloquently, in exploring why it is unnecessary to invoke God to light the blue touchpaper and set the universe in motion.

An instant after the Big Bang, the cosmos was smaller than an atom. It is here that the best theory physicists have for understanding the science at this atomic level comes into play: quantum mechanics. Often counter-intuitively, this describes an atomic reality where “virtual” particles can pop in and out of existence in a time so short they cannot be seen but only inferred from circumstantial evidence.

Lawrence Krauss
“At the heart of quantum mechanics is a rule that sometimes governs politicians or CEOs – as long as no one is watching, anything goes,” explains Krauss. Given the size of the baby universe after the Big Bang, quantum mechanics suggests it is possible that space and time, like virtual particles, just pop out of nothing because “nothing” is an unstable state. This is a concept of “nothing” far removed from the ordinary usage of the word: in quantum physics it is full of potential and possibilities, always poised on the verge of something.

So why does the universe exist? “Ultimately,” Krauss admits, “this question may be no more significant or profound than asking why some flowers are red and some are blue.” Nevertheless, I am glad that there are scientists like him who will tackle it all the same. 

Wednesday, 7 March 2012

Higgs Force

Higgs Force: The Symmetry-Breaking Force that Makes the World an Interesting Place by Nicholas Mee

Literary Review, March 2012

Last December, with the Internet having been awash with rumours for weeks, saw the official announcement of the latest results in the search for the Higgs particle from the fellowship of the ring – the physicists working at CERN’s 27km circular Large Hadron Collider (LHC). The Higgs is the missing piece of the theory that describes the behaviour of fundamental particles and the forces that act between them. It plays a special role in giving all the other particles mass.

The teams running the two giant detectors at the LHC independently put the mass of the Higgs, which is measured in what physicists call gigaelectron volts (GeV), somewhere between 116–130 and 115–127 GeV respectively. Although the scope of the search for the Higgs has now been narrowed, particle physicists demand an extraordinary degree of precision in their measurements. As the CERN press release made clear, even a 98 per cent chance of being correct is ‘not yet strong enough to claim a discovery’.

Particle collisions at CERN
If all the data generated by the LHC were stored on CDs it would fill more than a million every second. This is one of the more astonishing facts that Nicholas Mee reports in his book Higgs Force. To overcome this problem detectors are designed to be highly selective about the data passed on for storage. When the LHC smashes beams of particles together there are a billion or so collisions per second within the ATLAS detector alone, yet only the data from a couple of hundred collision events that have the telltale signs of interesting and possibly new physics are recorded.

The system that performs the selection process and determines which information is discarded and which is stored for analysis is called the trigger. Nicholas Mee acts as the trigger as he selects the tales to tell of those whose work has helped reveal the structure of matter and the laws of nature, culminating in the present hunt for the Higgs particle. The result is an intellectual journey that ends at the LHC near Geneva but begins with the Big Bang 13.75 billion years ago.

When the universe was born there was only a single force, which Mee calls the Higgs force. Moments after its birth the temperature began to fall as the universe expanded and the original force was shattered into four disparate pieces. The strong force would hold the quarks together in the atomic nucleus, while the weak force would transmute matter and make the different elements. The electromagnetic force would bind atoms and control their chemical reactions, and then there was gravity. Mee focuses on the three forces that matter when it comes to particle physics – electromagnetism, weak and strong – and attempts the difficult task of trying to explain how physicists have discerned that although ‘the universe began in a perfectly symmetrical state, the Higgs broke this symmetry and enabled the matter that formed within the universe to evolve into complex and diverse structures’. Without the Higgs particle the universe would have remained in a state that was ‘homogeneous, lifeless and uninteresting’.

Most people have an intuitive feel for what symmetry means. They recognise symmetrical patterns when they see them. However, physicists understand symmetry in terms of transformation, such as a reflection in a mirror, a rotation around an axis or a translation through space. An object or a pattern possesses a symmetry if it does not change when it is transformed in some way. For instance, if a snowflake is rotated around its centre by sixty degrees (one sixth of a complete revolution), it will appear exactly the same after the rotation as it did before. In fact all rotations through multiples of sixty degrees are symmetries of a snowflake.

Symmetry has become fundamental to the way that physicists view the universe, and an increased understanding of the symmetries of nature has been one of the major themes in the development of physics. When a quantity remains unchanged throughout a physical encounter it helps physicists to disentangle the details of what might be an extremely complicated event. This is true of the collisions that take place at the LHC. Mee does an admirable job of explaining all this before tackling ‘spontaneous symmetry breaking’, which lies at the heart of the Higgs story.

Peter Higgs
This book is far broader and more accessible than its title may suggest. For instance, we learn that the scientific investigation of magnetism dates back to William Gilbert, the personal physician of Elizabeth I. He was one of the first to try to understand the workings of nature through experimentation rather than philosophical argument. He concluded from his many experiments that the Earth is a magnet, explaining why a compass needle points north. Among others that we meet is a physicist who compared his power to transmute the elements to the mythical alchemist Hermes Trismegistus; an astronomer who was captivated by the beauty of a falling snowflake; the British physicist whose work predicted the existence of antimatter; the theorist who transformed particle physics with his eightfold way; and Peter Higgs, whose long wait for the discovery of the particle that bears his name may soon be over.

Friday, 24 February 2012

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’. 

How the Hippies Saved Physics

How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival by David Kaiser 

Financial Times, 14-15 January 2012

Quantum teleportation may sound like science fiction, but in 1997 a team led by Austrian physicist Anton Zeilinger turned it into a scientific fact. A single particle was transported, not physically but through transferring its quantum properties to a second particle, thereby effectively teleporting it from one place to another. Although not as dramatic as Captain Kirk being “beamed up”, it was nonetheless a stunning demonstration of a process deemed impossible just a decade earlier.

Even more remarkable is the fact that quantum teleportation and – for example – the ideas that underpin quantum-encrypted bank transfers have their origins in the hazy, drug-fuelled excesses of the 1970s New Age movement. As David Kaiser, a physicist at the Massachusetts Institute of Technology, explains in How the Hippies Saved Physics, many of the concepts at the heart of today’s science of quantum information can be traced back to a freewheeling circle of young physicists involved in an informal discussion group founded in May 1975 at the Lawrence Berkeley National Laboratory in California.

Calling themselves the “Fundamental Fysiks Group” (FFG), they met weekly for nearly four years as they sought to recapture the excitement and mystery that had attracted them to physics in the first place. Members came and went as the group organised workshops and conferences on everythingfrom LSD to extrasensory perception, clairvoyance, psychokinesis and eastern mysticism with a heavy dose of quantum physics – the science of the atomic and sub-atomic levels of reality where mind-bending, counterintuitive ideas are the norm. This heady cocktail was already being sipped in the very first meeting, as Fritjof Capra spoke about his then new book The Tao of Physics, in which he argued that parallels existed between quantum theory and eastern mysticism.

Kaiser, too, sees an interconnection between the FFG, quantum pioneers such as Albert Einstein and Niels Bohr, and the debate over what quantum physics reveals about the nature of reality. Einstein admitted to having spent a hundred times longer thinking about quantum physics than his theory of relativity and believed there was “a real world existing independently of perception”. Bohr, meanwhile, maintained that there was no objective reality but only an “abstract quantum description”.

By the time Capra and FFG members began studying physics in the 1960s and 1970s, the cold war imperative to find practical applications meant that such philosophical engagement had fallen out of fashion in favour of a “shut up and calculate” approach.

John Bell
What fascinates Kaiser is the mismatch between the FFG scientists’ “soaring intellectual aspirations and their modest professional platform” as they rescued Bell’s theorem – one of the great achievements of 20th-century physics – from a decade of obscurity. In 1964 John Bell managed to discover what had eluded both Einstein and Bohr: a mathematical theorem that offered a way of deciding between their opposing world views. Bell’s theorem stipulated that quantum objects that had once interacted with each other would retain a strange connection. Nudge a particle here and its partner would instantaneously dance over there – they remained “entangled” regardless of whether they were nanometres or light years apart.

Entanglement, for the likes of Capra, was akin to the eastern mystics’ emphasis on holism. Not everyone may have followed him there, but as the FFG grappled with Bell’s theorem it forced more conventionally minded physicists to pay attention. Today only the provenance of its successes would raise an eyebrow. Like so many of their peers, the hippies who “saved” physics have been absorbed by the mainstream. 

How To Build A Time Machine

How To Build A Time Machine: The Real Science of Time Travel by Brian Clegg 

New Scientist, 10 December 2011

At 10pm on Saturday May 7 2005, some 400 people waited at the Massachusetts Institute of Technology for some very special guests to arrive. Time travellers from any and every point in the future had been invited to join the party in Cambridge. “The idea was a simple one that might at first seem trivial but was, in fact rather clever,” Brian Clegg explains in How to Build a Time Machine. “If time travel is possible, why not flag up a certain place and time in history and invite time travellers to attend?” 
The organisers had tried to ensure that the relevant information seeped into the future, and hoped a combination of the internet, print media and TV coverage would do the job. How could any curious, party-loving time traveller resist?

The no-show raises a simple question about the possibility of travelling back in time: We may not yet have the technology to move freely through the ages, but if time machines are going to be built at some point in the future, why hasn't anyone come back to visit us? According to the theory of special relativity, as one moves faster and faster and approaches the speed of light, time slows down. At the speed of light, time stands still. If one could go faster than light, then in principle it is possible to travel back in time. So, Clegg asks, “Where are the time travellers?”

Accelerating beyond light speed to go back to the future requires an infinite of energy, so is practically ruled out (though a huge question mark hangs over faster-than-light neutrinos). However, general relativity does permit the construction of a time machine if space-time is twisted to create a loop, allowing a traveler heading into the future to circle back to an event in his or her own past. This is possible in curved space-time because it’s like a rollercoaster with a loop-the-loop: the cars always go forward but the track circles back to a previous point. 

If a time machine is constructed in the year 2100, for example, it means the loop in space-time starts then: the time machine can be used to go back to 2100 but not to a time before. This feature of time machines has been suggested by physicists J. Richard Gott and Kip Thorne - the former using cosmic strings and the latter, wormholes. Time travel is possible machine when strings cross or wormhole mouths are moved.

Despite its impracticality, Clegg believes it’s never too soon to consider the potential social and ethical impact of a functioning time machine. He devotes a chapter to the classic “grandfather paradox” - travelling back in time to kill your grandfather before he ever meets your grandmother, rubbing yourself out of existence. It was to handle such conundrums that Stephen Hawking suggested the chronology protection conjecture - the laws of physics conspire to prevent time travel to the past on a macroscopic scale.

H G Wells
Though 116 years have passed since H.G. Wells published his novella, The Time Machine, it is only in recent decades that time travel has leapt from the pages of science fiction to those of physics journals.  While Clegg offers an introduction to time travel, unlike the preceding How to Build a Time Machine by Paul Davies or Gott’s Time Travel in Einstein’s Universe, he doesn't offers much new understanding. In surveying the basics he does conclude – somewhat reassuringly – that,  “time travel technology is not something an amateur can cobble together in the garage”, and that when it does happen it will be down to sophisticated science, “subject to checks and safeguards”. In the end, I suppose, only time will tell.

Thursday, 29 December 2011

The Infinity Puzzle

The Infinity Puzzle: How the quest to understand quantum field theory led to extraordinary science, high politics, and the world's most expensive experiment by Frank Close

Literary Review, December 2011

‘A desk or table, a chair, paper and pencils,’ was what Einstein asked for in 1933 when he arrived at the Institute for Advanced Study in Princeton. Then he remembered one last item: ‘Oh yes, and a large wastebasket, so I can throw away all my mistakes.’ In the next two decades before his death in 1955 there were plenty of them, but Einstein had earned the right to make those mistakes in search of his holy grail – a unified field theory.

In 1864 the Scottish physicist James Clerk Maxwell showed that electricity and
magnetism were different manifestations of the same underlying phenomenon – electromagnetism. His great achievement was to encapsulate the disparate behaviour of electricity and magnetism into a set of four elegant mathematical equations that were to be the crowning glory of nineteenth-century physics.

Einstein sought a single, all-encompassing theoretical structure that would unify electromagnetism with his theory of gravity, the general theory of relativity. Such a unification was the logical next step for Einstein, but few were convinced, for in the twentieth century two new forces were discovered and given names that alluded to their strengths relative to the electromagnetic: the so-called strong and weak forces.

The strong force is the binding force that holds atomic nuclei together; conversely the weak force destabilises nuclei, causing a form of radioactivity that plays an essential role in the way that the sun produces its energy. As the years passed the belief grew that these four forces – electromagnetism, gravity, and the strong and weak forces – would be reunited in a Theory of Everything.

With the exception of general relativity, physicists have been able to ‘quantize’ the other three forces, since quantum mechanics deals with the atomic and sub-atomic domain. In effect they managed to get three trains running on the same size track. The quantum gravity train is still stuck at the station. In The Infinity Puzzle Oxford particle physicist Frank Close tells the tale of quantum field theory – the attempts to understand and then unite electromagnetism and the strong and weak forces.

In the 1930s the union of Maxwell’s theory of electromagnetism, Einstein’s theory of special relativity, and quantum mechanics gave birth to a theory of the electromagnetic force known as quantum electrodynamics, or QED. However, in the bowels of the theory lurked a monster – infinity. The equations of QED kept predicting that the chance of some things occurring was ‘infinite’. When infinity pops up in physics it spells disaster since, as Close explains, it is ‘proof that you are trying to apply a theory beyond its realm of applicability’. In the case of QED, if you can’t calculate something as basic as a photon – a particle of light – interacting with an electron without getting infinity, you haven’t got a theory.

It was the late 1940s before a way was found to solve the infinity puzzle in QED by a process called renormalisation. The calculations of many properties of atoms and their constituent particles, including those for the mass and charge of an electron, gave infinity as the answer. However, these two quantities of the electron had already been measured to a high degree of precision using other methods and the results were sufficient to provide benchmarks for anything else physicists wished to compute in QED. Instead of infinity, many of the answers now turned out to be finite and correct. Some physical quantities that have been calculated using renormalisation agree with earlier experiments to an accuracy of one part in a trillion, which is an order of magnitude akin to the diameter of a hair when compared to the width of the Atlantic.

Renormalisation may have been inelegant but its ‘recipe for extracting sensible answers for QED worked’. Those who cooked it up independently of each other – Richard Feynman, Julian Schwinger and Sin-Itiro Tomonaga – won a share of the 1965 Nobel Prize in Physics.

Gerard 't Hooft
When it came to the weak force, infinity was not so easy to banish, even with the efforts of the world’s leading physicists over a quarter of a century. It was the brilliant Dutch postgraduate student Gerard ’t Hooft who finally found a solution. The nature of the problem, how it was solved, and the inevitable jostling for Nobel Prizes are major themes of Close’s gripping and extensively researched narrative history of particle physics over the last sixty years.

It may be a collective enterprise but, as Close’s book reveals, science is full of wrong turns, partial answers, missed opportunities and misunderstandings. How could it be otherwise, since the dispassionate, logic-driven stereotype of the scientist is a fiction? The physicists in The Infinity Puzzle ‘experience the same emotions, pressures and temptations as any other group of people, and respond in as many ways’.

A timeline of who did what when, together with a glossary, could be added to the paperback, to help readers as they grapple with gauge invariance, parity violation, spontaneous symmetry breaking, gluons, colour, the Higgs boson and SU(2)xU(1). Yet Close has succeeded in humanising a dramatic era of physics in what is my science book of the year. Some sections of his narrative are difficult because of the inherent nature of the ideas he’s trying to explain. But then, it took exceedingly clever people to devise them.

‘Hold Infinity in the palm of your hand,’ William Blake wrote in the ‘Auguries of Innocence’. Frank Close does a fabulous job of reconstructing how physicists like Feynman and ’t Hooft managed to do exactly that.