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.

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’.

The Quantum Universe

The Quantum Universe: Everything that can happen does happen by Brian Cox and Jeff Forshaw

Daily Telegraph, 22 October 2011

More than 10,000,000,000, 000,000,000 transistors are manufactured each year. For an idea of the magnitude of this number, it is roughly 100 times greater than all the grains of rice consumed annually by the people of planet Earth. This astonishing fact about the fundamental building block of all electronic devices is buried deep within The Quantum Universe, the latest book from Brian Cox and Jeff Forshaw.The very first transistor computer built in 1953 had just 92 transistors, but today more than 100,000 can be bought for the cost of a single grain of rice and there are around a billion of them in a mobile phone. It is easy to see why Cox and Forshaw believe the invention of this device was “the most important application of quantum theory”, while the theory itself is “the prime example of the infinitely esoteric becoming the profoundly useful”.

It is esoteric because the theory describes a reality in which a particle can be in several places at once and moves from one place to another by exploring the entire universe simultaneously. The American physicist Richard Feynman unveiled a piece on the quantum universe, but nevertheless cautioned: “I think I can safely say that nobody understands quantum mechanics. Do not keep asking yourself, if you can possibly avoid it, ‘But how can it be like that?’ Nobody knows how it can be like that.”

Heeding this advice and sticking to the maxim that “following the rules is far simpler than trying to visualise what they actually mean”, Cox and Forshaw set out to “demystify quantum theory”. If they do not entirely succeed, it says more about the size of the task they have set themselves than its execution. The word “quantum”, they warn at the outset, is at “once evocative, bewildering and fascinating”. Having written a narrative history myself with that one word as a title, I know exactly what they mean.

Peppered with diagrams and equations, The Quantum Universe is not an easy read. We encounter Planck's constant (nature’s own axe for chopping up energy and much else besides); the principle of least action; the wave function; the uncertainty principle; electron standing waves; the exclusion principle; semiconductors; Feynman diagrams; quantum electrodynamics; the Higgs boson and the standard model of particle physics. The reader is made to work along the way and for those prepared to do so there is much to learn. Why, for example, empty space isn’t empty but is a seething maelstrom of subatomic particles.

While they sidestep the question of its interpretation and the decades-long debate between Albert Einstein, Niels Bohr and others, for Cox and Forshaw there is no better demonstration of the power of the scientific method than quantum mechanics. Nobody could have come up with the theory without the aid of detailed experiments, and the physicists who came up with it were forced to suspend and then discard their previously held beliefs to explain the evidence that confronted them. In an attempt to convince any sceptical readers about the power of quantum mechanics, the authors turn to the death of stars and the Chandrasekhar limit as they champion curiosity-driven research.

The sun is a gaseous mix of protons, neutrons, electrons and photons with the volume of a million earths that is slowly collapsing under its own gravity. This compression heats the core to such temperatures that protons fuse together to form helium nuclei. The fusion process releases energy that increases the pressure on the outer layers of the star, thus balancing the inward pull of gravity. And so it will go on for the next five billion years until the sun runs out of material to fuse and ends up as a super dense ball of nuclear matter in a sea of electrons known as a white dwarf. It’s a fate that will befall more than 95 per cent of the stars in our galaxy. Though the highlight of the book is confined to the epilogue, Cox and Forshaw show how it’s possible to approximately calculate the largest possible mass of these stars.

The detailed and more complex calculation was originally published in 1931 by the Indian astrophysicist, and future Nobel laureate, Subrahmanyan Chandrasekhar. It led to two remarkable predictions: white dwarf stars exist and they cannot have a mass greater than 1.4 times that of the sun. Astronomers have catalogued some 10,000 white dwarves and the largest recorded mass is just under 1.4 solar masses. Depending on four of nature’s fundamental numbers – Planck’s constant, the speed of light, Newton’s gravitational constant and the mass of the proton – Chandrasekhar’s limit is a stunning triumph of the scientific method. “The eternal mystery of the world is its comprehensibility,” Einstein wrote. “The fact that it is comprehensible is a miracle.”

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?”

From Eternity to Here

From Eternity to Here: The Quest for the Ultimate Theory of Time by Sean Carroll

Daily Telegraph, 9 April 2011

‘What is time?” It’s the sort of question asked by philosophers, physicists and, sooner or later, children. While reading From Eternity to Here I was relieved that my eight-year-old was actually asking “What is the time?” That was a question I could answer. As for the other, most of us would side with St Augustine: “If no one asks me, I know. If I wish to explain it to one that asketh, I know not.”

St Augustine, having tackled original sin, contemplated the nature of time and concluded that “neither future nor past exists, and it is inexact language to speak of three times – past, present and future”. There, in a nutshell, is the problem that Sean Carroll, a theoretical physicist at the California Institute of Technology, explores in this fascinating book. Why is there a past, present and future? In other words, why is there an “arrow of time”?

Before Einstein, it had long been assumed that time and space were fixed and distinct, the stage on which the never-ending drama of the cosmos was played out. Einstein discovered space and time were not absolute and unchanging, that spatial distances and time intervals between events depended on the relative motion of observers. He found that space and time were woven together to form the fabric of the universe: space-time.

Yet there is one crucial difference between space and time. While it is possible to move in any direction in space, the ticks of a clock forever march time forward. This inexorable flight of time’s arrow from past to present to future is bound up with the second law of thermodynamics. Put simply, the amount of disorder, what physicists call entropy, increases with the passage of time.

Breaking eggs to make an omelette, stirring milk into coffee or spilling wine all exhibit, says Carroll, “the fundamental irreversibility that is the hallmark of the arrow of time”.It is the increase in entropy, in the disorderliness of the world, which makes these everyday events irreversible and separates the past from the future. Eggs can’t spontaneously unscramble or spilt wine jump back into the bottle because that would lead to a decrease in entropy. But why should entropy always increase?

“Understanding the arrow of time is a matter of understanding the origin of the universe,” Carroll argues. For him the reason we can’t unscramble an egg is due to the low entropy conditions in the early universe some 13 billion years ago. Attempting to explain how such a low entropy state was possible has led Carroll to become one of an increasing number of physicists who in recent years have begun to question whether the Big Bang was really the beginning of the universe. For him it is “simply a plausible hypothesis, not a result established beyond reasonable doubt” and it is conceivable that space and time extend beyond the moment that we identify as “the Big Bang”.

Traditionally, questions about what was there “before the Big Bang” have been dismissed as meaningless, since space and time were deemed to be created at the Big Bang there simply was no “before”. Instead of the universe, theorists now talk of the “multiverse” and “baby universes” that Carroll believes provide “a natural mechanism for creating more and more entropy in the universe”.

From Eternity to Here is not for the faint hearted, but it’s a rewarding read because there are no answers yet to some of science’s toughest questions.“There are ideas, and some ideas seem more promising than others, but all of them are somewhat vague, and we certainly haven’t yet put the final pieces together,” admits Carroll as he guides the reader through some of the most exotic parts of the landscape of modern theoretical physics and cosmology: from evaporating black holes to wormhole construction, from the many worlds interpretation to cosmic inflation.

But the question remains: “what is time?” The response of the American physicist John Wheeler is worth remembering: “Time is nature’s way of keeping everything from happening at once.”