The Universe Within (22 page)

As I discussed in Chapter Three, one of string
theory
's features is that it requires the existence of extra dimensions of space. In addition to the familiar three dimensions of space — length, height, and breadth — the simplest string theories require six more space dimensions, and M-theory, which I also described, requires one more, bringing the number of extra dimensions to seven. The six extra dimensions of string theory can be curled up in a little ball, so small that we would not notice them in today's universe. And the seventh dimension of M-theory is even more interesting. It takes the form of a gap between two three-dimensional worlds. This picture was the basis for the cyclic model of cosmology that I explained in the previous chapter.

Although there were great expectations that string theory would solve the problem of the unification of forces, these hopes have also dimmed. The main problem is that, like grand unified theories, string theory is itself too arbitrary. For example, it turns out to be possible to curl up the six or seven extra dimensions in an almost infinite number of ways. Each one would lead to a three-dimensional world with a different pattern of particles and forces. Most of these models are hopelessly unrealistic. Still, many researchers hope that by scanning through this “landscape” of possible string theory universes, they may find the right one. Some even believe that every one of these landscapes of universes must be realized somewhere in the actual universe, although only one of them would be visible to us. This picture, called the “inflationary multiverse,” has to be one of the most extravagant proposals in the history of science.

From my own point of view, none of these string
theory
universes is yet remotely realistic, because string theory has so far proven incapable of describing the initial singularity, the problem I outlined in the previous chapter. The string theory landscape, so far as it is currently understood, consists of a set of empty universe models. But there are serious grounds for doubt as to whether these empty models can actually be used to describe expanding universes full of matter and radiation, like ours.

Rather than speculate about a “multiverse” of possible universes, I prefer to focus on the one we know exists, and try to understand the principles that might resolve its major puzzles: the singularity and the distant future. String theory is a powerful theoretical tool that has already provided completely new insights into quantum gravity. But there is some way to go before it is ready to convincingly describe our universe.

THE SITUATION IN WHICH
string theory finds itself is in many ways a reflection of how fundamental physics developed over the course of the twentieth century. In the early part of the century came the great ideas of quantum physics, spacetime, and general relativity. There was great philosophical richness in the debates over these matters, with much fewer publications and conferences than today, and a greater premium on originality. In the late 1920s, with the establishment of quantum theory and the quantum theory of fields, attention turned to more technical questions. Physicists focused on applications and became more like technicians. They extended the reach of physics to extremely small and large distances without having to add any revolutionary new ideas.

Physics became a fertile source of new technologies — everything from nuclear power to radar and lasers, to transistors,
LED
s, integrated circuits and other devices, to medical X-ray,
PET
, and
NMR
scans, and even superconducting trains. Particle accelerators probing very high energies made spectacular discoveries — of quarks, of the strong and electroweak forces, and most recently of the Higgs boson. Cosmology became a true observational science, and dedicated satellites mapped the whole universe with exquisite precision. Physics seemed to be steaming towards a final answer, towards a theory of everything.

From the 1980s on, waves of enthusiasm swept the field only to die out nearly as quickly as they arose. Publications and citations soared and conferences multiplied, but genuinely new ideas were few and far between. The mainstreaming of grand unification and string
theory
, and the sheer pressure it created to force a realistic model out of incomplete theoretical frameworks so far has been dissatisfying.

The development in physics is, I think, a kind of ultraviolet catastrophe, like the one Planck and Einstein discovered in classical physics at the start of the twentieth century. They are consequences of mechanical ways of thinking. I believe it is time for physics to step away from contrived models, whether artificial mathematical constructs or
ad hoc
fits to the data, and search for new unifying principles. We need to better appreciate the magic we have discovered, and all of its limitations, and find new ways to see into and beyond it.

Every term in our formula required a giant leap of the imagination — from Einstein's description of gravity, to Dirac's description of the electron and other particles, to Feynman's formulation of quantum mechanics as a sum over all possible histories. We need to foster opportunities for similar leaps to be made. We need to create a culture where the pursuit of deep questions is encouraged and enabled: where the philosophical richness and depth of an Einstein or Bohr combine with the technical brilliance of a Heisenberg or Dirac.

As I have emphasized, some of the greatest contributions to physics were made by people from very ordinary backgrounds who, more or less through chance, came to work on fundamental problems. What they had in common was the boldness to follow logical ideas to their conclusion, to see connections everyone else had missed, to explore unknown territories, and to play with entirely new ideas. And this boldness produced leaps of understanding way beyond everyday experience, way beyond our circumstances and our history, leaps which we can all share.

· · ·

WHEN CHILDREN GO TO
school, we teach them algebra and geometry, physics according to Newton's laws, and so on, but as far as I know, nobody says anything about the fact that physics has discovered a blueprint of the universe. Although the formula takes many years of study to fully understand and appreciate, I believe it is inspirational to realize how far we have come towards combining the fundamental laws that govern the universe.

In its harmonious and holistic nature, the formula is, I believe, a remarkable icon. All too often, our society today is driven by selfish behaviour and rigid agendas — on the one hand by people and groups pursuing their own short-term interests, and on the other by appeals to preconceived systems that are supposed to solve all our problems. But almost all of the traditional prescriptions have failed in the past, and they are all prone to being implemented in inhuman ways. It seems to me that as we enter a period of exploding human demand and increasingly limited resources, we need to look for more intelligent ways to behave.

The formula suggests principles that might be more useful. In finding the right path for society, perhaps we need to consider all paths. Just as quantum theory explores all options and makes choices according to some measure of the “benefit,” we need to run our societies more creatively and responsively, based on a greater awareness of the whole. The world is not a machine that we can set in some perfect state or system and then forget about. Nor can we rely on selfish or dogmatic agendas as the drivers of progress. Instead, we need to take an informed view of the available options and be far-sighted enough to choose the best among them.

It is all too easy to define ourselves by our language, nationality, religion, gender, politics, or culture. Certainly we should celebrate and draw strength from our diversity. But as our means of communications amplify, these differences can create confusion, misunderstanding, and tension. We need more sources of commonality, and our most basic understanding of the universe, the place we all share, serves as an example. It transcends all our differences and is by far the most reliable and cross-cultural description of the world we have. There is only one Dirac or Einstein or Maxwell equation, and each of these is so simple, accurate, and powerful that people from any and all backgrounds find it utterly compelling. Even the failures of our formula are something we can all agree about.

And that, I think, will be the key to future scientific breakthroughs. If you look at the people who made the most important contributions in the past, many were among the first members of their societies to get involved in serious science. Many faced discrimination and prejudice. In overcoming these obstacles they had a point to prove, which encouraged them to question traditional thinking. As we saw in Chapter Two, many of the most prominent twentieth-century physicists were Jewish, yet until the mid-nineteenth century Jews had been deliberately excluded from science and technical subjects at many universities across Europe. When they finally gained access, they were hugely motivated to disprove their doubters, to show that Jews could do every bit as well as anyone else. Einstein, Bohr, Born, and Noether were part of an influx of new talent that completely revolutionized physics in the early twentieth century.

Which brings me back to the question of unification, both of people across the planet and of our understanding of the world. The search for a superunified theory is an extremely ambitious goal.
A priori
, it would seem to be hopeless: we are tiny, feeble creatures dwarfed by the universe around us. Our only tools are our minds and our ingenuity. But these have enabled us to come amazingly far. If we think of the world today, with seven billion minds, many in emerging economies and societies, it is clear that there is a potential gold mine of talent. What is needed is to open avenues for gifted young people to enter and contribute to science, no matter what their background. If opportunities are opened, we can anticipate waves of motivated, original young people capable of transformative discoveries.

Who are we, in the end? As far as we know, we represent something very rare in the universe — the organization of matter and energy into living, conscious beings. We have learned a great deal about our origins — about how the universe emerged from the singularity filled with a hot plasma; how the chemical elements were created in the big bang and stars and supernovae; how gravity and dark matter clumped molecules and atoms together into galaxies, stars, and planets; how Earth cooled and allowed lakes and oceans to condense, creating a primordial soup within which the first life arose. We do not know exactly how life started, but once the first self-regulating, self-replicating organisms formed, containing the
DNA
-protein machinery of life, reproduction, competition, and natural selection drove the evolution of more and more complex living organisms. We humans stand now on the threshold of a new phase of evolution, in which technology will play as much of a role as biology.

Great mysteries remain. Why did the universe emerge from the big bang with a set of physical laws that gave rise to heavy elements and allowed complex chemistry? Why did these laws allow for planets to form around stars, with water, organic molecules, an atmosphere, and the other requirements for life? Why did the
DNA
-protein machinery, developed and selected for in the evolution of primitive single-cell organisms, turn out to be able to code for complex creatures, like ourselves? How and why did consciousness emerge?

At every stage in the history of the universe, there was the potential for vastly more than what had been required to reach that stage. Today, this is more true than ever. Our understanding of the universe has grown faster than anyone could have imagined a century ago, way beyond anything that could be explained in terms of past evolutionary advantage. We cannot know what new technologies we will create, but if the past is any guide, they will be extraordinary. Commercial space travel is about to become a reality. Quantum computers are on the horizon, and they may completely transform our experience of the world. Are all these capabilities simply accidental? Or are we actually the door-openers to the future? Might we be the means for the universe to gain a consciousness of itself?

FIVE

THE OPPORTUNITY OF ALL TIME

Whence things have their origin,
Thence also their destruction happens,
As is the order of things;
For they execute the sentence upon one another
— The condemnation for the crime —
In conformity with the ordinance of Time.
— Anaximander
81

ANAXIMANDER'S QUOTE MIGHT HAVE
been meant for today: our world is changing rapidly, with our future in the balance.

Our global population has grown to seven billion and continues to rise. We are eating away at our supplies of energy, water, fertile land, minerals. We are spoiling our environment and driving species extinct every day. We are caught up in financial and political crises entirely of our own creation. Sometimes it feels as if the technological progress on which we have built our lives and our societies is just leading us towards disaster. There is an overwhelming sense that we are running out of time.

Our personal capabilities have never been greater.Many of us can now communicate instantly with collaborators, friends, and family around the globe. This ability has powered new democratic movements, like those of the Arab Spring, and has allowed the assembly of great stores of collectively curated information, like Wikipedia. It is driving global scientific collaborations and opening online access to quality educational materials and lectures to people everywhere.

But the internet, with all of its attractions, is also profoundly dehumanizing. Increasingly we are glued to our computers and smartphones, building our social and professional lives around email, social media, blogs, or tweets. Overload of digital information turns us into automata, workaholics, passive consumers. Its harsh physical form stresses us and creates a mismatch between our own human nature and the manner in which we are being forced to communicate. Our analog nature is being compressed into a digital stream. Not so surprising then that, as the comedian Louis C. K. recently put it, “Everything is amazing right now and nobody's happy.”
82

Massive economic shifts are also taking place. Past political paradigms are becoming irrelevant, with Western governments intervening to shore up their financial systems, and China overseeing the world's greatest market-driven economic boom. Information is the new oil, and knowledge-based companies like Google, Amazon, and Facebook are replacing manufacturing industries in many developed Western countries. Instead of the old worker–owner division, Western society is developing new fractures: between an economically active elite and a marginalized remainder.

Short-term thinking is endemic, as is natural when things are moving fast. It is as if we are driving a speeding car through a fog, swerving to avoid potholes, roadblocks, or oncoming vehicles, anxiously anticipating the dangers with no power to predict them. Politicians tend to think no further than the next election, scientists no further than the next grant.

In this chapter, I want to talk about the future of this world of ours. The coming century will see our lives, and those of our children, transformed. What happens will depend on the decisions we take and on the discoveries we make. I won't make any forecasts. Nor will I try to outline a plan for our survival. That is a pragmatic task requiring the skills and dedication of many people.

Instead, I want to try to step back from all the anxieties and the immediate issues of today and address something more basic and long-term, namely our own human character: how our ideas regarding our place in the universe may develop, and how our very nature may change. Speaking about the future makes us nervous. Einstein said, “I never think of the future; it comes soon enough.” We do not really know who we are or what we are capable of. I feel like a diver standing on the edge of a tall cliff, looking over the precipice and peering through the fog below. Is there a beautiful, cool ocean waiting for me, or only jagged rocks? I don't know. Nevertheless, I will take the plunge.

As I will explain, scientific advances we can now envisage may bring us, as living, self-conscious beings, much closer to physical reality. The separation of our ideas from our nature, of science from society, of our intellect from our feelings, and of ourselves from the universe may diminish. Not only might we see the universe more clearly, but we may come to know it more deeply. And in time, that knowledge will change who we are. This is an extraordinary prospect, which I hope will encourage us to see a more inspirational future.

THINKING ABOUT THE UNIVERSE
might seem like escapism, or a luxury: how will it solve the problem of world hunger, or carbon emissions, or the national debt? But throughout history, from Anaximander and Pythagoras to Galileo and Newton, the universe has been an endless source of wonder, inspiring us to rise above our current circumstances and see what lies beyond. That basic urge continues today, driving the creation of the most powerful ever microscope — the Large Hadron Collider — and the most powerful ever telescope — the Planck satellite. It has resulted in a working mathematical model of all the forces and particles in nature, tested to precision from length scales well below the size of an atomic nucleus up to the entire visible universe. We understand the broad features of the evolution of the cosmos, from its first microseconds up to the spectacular present, where we see hundreds of billions of galaxies stretching across space. The Higgs particle — a manifestation of the mechanism through which matter particles and forces acquire their distinctive characters — has just been discovered, one of physics' crowning achievements.

Discoveries as basic as this one can take a long time for their full impact to be felt. But the more basic they are, the more profound the impact. Quantum physics was formulated in the 1920s, but it was not until the 1960s that its implications for the nature of our reality began to be more fully appreciated. We think of and discuss the world as if it were an arena filled with definite things, whose state changes from one moment to the next. This is the picture of the classical universe, as developed by Newton, Maxwell, and Einstein, evolving according to deterministic physical laws.

Quantum
theory
makes predictions that are inconsistent with this picture, and experiment shows them to be right. According to quantum theory, the world is constantly exploring all of its possible classical states all of the time, and is only appearing to us as any one of them with some probability. The conceptual machinery that underlies this view of quantum reality involves strange mathematical concepts like the square root of minus one, for which we have little intuition. And only now are the technological implications of these basic discoveries becoming apparent.

At the same time, fundamental research continues to identify new avenues for expanding the boundaries of our knowledge. As successful and far-reaching as our modern picture of the universe is, our description completely fails at the critical event — the big bang singularity — from which everything we now see around us emerged. Our current understanding likewise offers little explanation for the universe's strange future. The energy of empty space — the vacuum energy, which is itself controlled by quantum effects — has taken over as the dominant form of energy in the universe. In the coming tens of billions of years, its repulsive gravitational force will speed up the expansion of the universe and carry all the galaxies we now see out of our view. As Anaximander said, our world is transitory, and the physical forces that enabled its emergence are now in the process of taking it away.

The theories of the twentieth century are struggling to tackle these problems — of the emergence of the universe and of its ultimate fate. String theory is the leading contender for a “theory of everything,” possessing exciting mathematical properties that suggest it might include every known force and particle. But string theory comes along with tiny extra dimensions of space, so small they are invisible, whose form fixes the pattern of forces and particles we should see. Unfortunately, the theory does not make any definite prediction for the form of the extra dimensions, and with our present understanding, the number of possible configurations seems almost uncountable. For each one of these configurations, the universe consisting of the visible dimensions and the particles and forces within them would appear very different. String theory therefore seems to predict a “multiverse” rather than a universe. Instead of being a theory of everything, it is more like a theory of anything.

String theory's lack of a definite prediction for the vacuum energy, combined with the puzzling observation that the vacuum energy takes a tiny positive value, has encouraged many scientists to embrace what seems to many of us like an unscientific explanation: that every one of these universes is possible, but the one we find ourselves in is the only one that actually allows us to exist. Sadly, this idea is at best a rationalization. It is hard to imagine a less elegant or convincing explanation of our own beautiful world than to invent a near-infinite number of unobservable worlds and to say that, for some reason we cannot understand or quantify, ours was “chosen” to exist from among them.

Most string theorists have likewise avoided the problem of the big bang singularity, although every one of their hypothesized worlds possesses such a starting point. Typically, they are content to assume the universe sprang into existence in one of the plethora of allowed forms, just after the singularity, and to discuss its evolution from there. So indeed, from the most widely accepted viewpoints, the beginning and the end of the universe seem to be brick walls beyond which physics cannot go.

The puzzles of the beginning and the future of the universe are, in my view, the critical clues which may help us rise above current paradigms and find a better vantage point. As I discussed in Chapter Three, we do have ways of conceptually taking the universe into the quantum domain, and these now suggest a very different picture, in which we may traverse the big bang singularity to a universe before it and likewise pass beyond our vacuous future into the next big bang to come. If this suggestion is correct, the implication is that there was no beginning of time nor will there be an end: the universe is eternal, into the past and into the future.

· · ·

OUR SOCIETY HAS REACHED
a critical moment. Our capacity to access information has grown to the point where we are in danger of overwhelming our capabilities to process it. The exponential growth in the power of our computers and networks, while opening vast opportunities, is outpacing our human abilities and altering our forms of communication in ways that alienate us from each other. We are being deluged with information through electrical signals and radio waves, reduced to a digital, super-literal form that can be reproduced and redistributed at almost no cost. The technology makes no distinction between value and junk. The abundance and availability of free digital information is dazzling and distracting. It removes us from our own nature as complex, unpredictable, passionate people.

The “ultraviolet catastrophe” that physics encountered at the end of the nineteenth century serves as a metaphor for physics today, as I have already suggested, and also for our broader crisis. Maxwell's theory of electromagnetic radiation and light was a triumph, being the most beautiful and powerful application of mathematics to describing reality. Yet it implied that there were waves of all wavelengths, from zero to infinity. In any realistic context, where heat and electromagnetic energy are constantly being exchanged between objects, this feature of Maxwell's theory leads to a disaster. Any hot object, or any electron in orbit around an atom, can radiate electromagnetic waves at an unlimited rate, leading to a disastrous instability of the world.

Planck was forced to tackle this problem by taking a step back from a literal, classical world as envisaged by Newton, Maxwell, and Einstein. Ultimately, we had to give up the idea of a definite reality comprising a geometrical arena — spacetime — inhabited by entities in the form of particles and waves. We had to give up any notion of being able to picture things as they really are, or of being able (even in principle) to measure and predict everything there is to know. These ideas had to be replaced with a more abstract, all-encompassing
theory
, which reduced our capacity to “know” or “visualize” reality, while giving us a powerful new means of describing and predicting nature.

In the same way, I believe we now need to step back from the overwhelming nature of our “digital age.” One can already see a tendency among many people to “surf” across the ocean of information on the internet. This behaviour seems to replace a desire for a deeper or more rounded understanding of anything. Mastery seems unfeasible in a world awash with information. However, higher level thinking is needed now more than ever. We need to develop more refined skills of awareness and judgement to help us filter, select, and identify opportunities. Collaboration will increasingly be the name of the game as people around the world work, share ideas, write books, and even construct mathematical proofs together.

Viewed in this light, our modes of education at school and university seem terribly outmoded. Young people don't need to memorize known facts any more — they are all readily accessible on the internet. The skills they need most are to think for themselves, to choose what to learn, to develop ideas and share them with others. How to see the big picture, how to find just what they need in an ocean of knowledge, how to collaborate and how to dig deep in an entirely new direction.

It seems to me we need to create a modern version of the ancient Greek philosophers' fora or Scotland's educational system in the late eighteenth century, where the principles and foundations of knowledge were questioned and debated, and where creativity, originality, and humility before the truth were the most highly prized qualities in a student.