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R E A LIT Y

EXISTENCE

GOD

CONSCIOUSNESS

LIFE

TI ME

SELF

SLEEP

DEATH

THE

BIGQUESTIONS

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The Big Questions | NewScientistThe Collectio

ONE of the most profound momentsin life is when, as a child, we first utterthat small but powerful word, why?

This is arguably what defines us a species.We are not so muchHomo sapiensasHomocuriosum. It is not hard to imagine our earliestancestor looking up at the stars, watching the

seasons change, or holding a newborn childand wondering: why?

Our curiosity knows no bounds and it hastaken us a long way, from the savannahs ofeast Africa to world domination and beyond.

Most of this progress has come in the past300 years thanks to the invention of asystematic way of asking questions andanswering them. That method is calledscience, and it has produced the greatestknowledge bounty ever.

But we still yearn to know why. There ismuch that we dont understand, and every

new discovery opens up new questions.This first issue ofNew Scientist: TheCollectionis dedicated to the wonders ofhuman curiosity. A compilation of classicarticles published inNew Scientist, it exploresthe profound questions we ask of ourselvesand the universe around us.

In Chapter 1 we ask perhaps the mostfundamental question of all: what is reality?Looking at the world around you, the answermight seem obvious until you dig deep, whenreality reveals itself to be a slippery customer.

Chapter 2 takes a more personal andreflective turn, asking what the discoveries of

modern science mean for our own existence,from the search for aliens to the bizarrepossibility that you are a hologram.

Chapter 3 casts a new perspective on one ofthe oldest answers in the book: thateverything can be explained by the existenceof an all-powerful supernatural being. We arenow largely dissatisfied with that answer, butGod continues to fascinate.

Chapter 4 returns to personal experiencespecifically the granite-hard problem of thenature of consciousness, how something soincredible can be produced by 1500 grams oso of brain tissue, and why you cannot be suthat everybody else is not a zombie.

Chapter 5 is dedicated to a phenomenon

that, as far as we know, is confined to a tinycorner of the universe: life itself. We know igot going on Earth almost as soon as theplanet was habitable but why did it take solong to give rise to complex creatures? Anddoes it have a future?

In Chapter 6, we probe one of theuniverses most puzzling dimensions: timeThe everyday ticking of a clock might seemthe most natural thing in the world, but itmasks a very peculiar phenomenon.

Chapter 7 focuses inwards again,dismantling the entity we call the self, whic

seems so solid and enduring to each of us anyet doesnt appear to actually exist.In Chapter 8 we explore the familiar yet

strange world of sleep and dreaming a plawe visit every night but which nonethelessremains eerie and elusive.

Finally, Chapter 9 faces up to the end.There is perhaps no older question abouthuman life than why it must one day cease.But viewed the right way, death can bothfascinate and inspire.

Graham Lawton, Editor

Big questions,bold answers

NEW SCIENTIST

THE COLLECTION

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EditorGraham Lawton

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PublisherJohn MacFarlane

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New Scientist The Collection is

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THE COLLECTION

THE BIGQUESTIONS


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CONTRIBUTORS

Sally Adee

is a feature editor atNew Scientist

Anil Ananthaswamyis a consultant for New Scientist

Justin L. Barrettis director of the Thrive Center for HumanDevelopment at Fuller Theological Seminaryin Pasadena, California

Stephen Battersbyis a consultant for New Scientist

Celeste Bieveris deputy news editor at New Scientist

Michael Bondis a consultant for New Scientist

Daniel Boris a cognitive neuroscientist at the SacklerCentre for Consciousness Science at theUniversity of Sussex in Brighton, UK

Michael Brooksis a consultant for New Scientist

Stephen Caveis a writer based in Berlin

Marcus Chown

is a consultant for New ScientistStuart Clarkis a consultant for New Scientist

Kate Douglasis a feature editor at New Scientist

Liam Drewis a neurobiologist at University College London

Liz Elseis an associate editor atNew Scientist

Richard Fisheris deputy editor of BBC Future

Jessa Gambleis a writer based in Yellowknife in CanadasNorthwest Territories

Linda Geddesis a feature editor at New Scientist

Amanda Gefteris a consultant for New Scientist

Mike Holdernessis a writer based in London

Valerie Jamiesonis chief features editor at New Scientist

Shelly Kaganis a professor of philosophy at Yale University

Nick Laneis a reader in evolutionary biochemistryat University College London

Graham Lawtonis deputy editor of New Scientist

Michael Le Pageis a feature editor at New Scientist

Robert N. McCauleyis director of the Center for Mind, Brain, andCulture at Emory University in Atlanta, Georgia

Ara Norenzayanis associate professor of psychology at theUniversity of British Columbia in Vancouver, Canada

David Robsonis a feature editor at New Scientist

Chris Sinhais a psychologist of language at LundUniversity in Sweden

Victor J. Stengeris emeritus professor of physics at the Universityof Hawaii and adjunct professor of philosophy at theUniversity of Colorado at Boulder

Dick Teresiis a writer based in Amherst, Massachusetts

Richard Webbis deputy features editor atNew Scientist

Jan Westerhoffis a philosopher at the University of Oxfordand the University of Londons School of Orientaland African Studies

Caroline Williamsis a science writer based in Surrey, UK

Clare Wilsonis a news reporter at New Scientist

Emma Youngis a writer based in Sheffield, UK

THE COLLECTION

2| NewScientist:The Collection|The Big Questions

2

3

Existence

1

God

Reality

THE BIGQUESTIONS

7 Defining reality

8 The bedrock of it all

9 Is matter real?

10 Is everything made of numbers?

13 If information then universe

15 Does consciousness create reality?

17 How do we know?

20 Why is there something rather than nothin22 Are we alone?

23 Am I a hologram?

24 Why is there a me?

26 Why is the universe just right?

28 How do I know I exist?

29 Is there more than one me?

31 Will we die out?

32 What happens when we become obsolete

33 Am I the same person I was yesterday?

34 How will it all end?

38 Born believers

42 The idea that launched a thousand civilisa

44 Natural religion, unnatural science

46 The god hypothesis

48 Religion without god

The articles in this collection were first

published in New Scientist between

April 2010 and May 2013. They have

been updated and revised.

OTT


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The Big Questions| NewScientist: The Collectio

63 Inevitable, fluke, or both?

68 The hot zone

72 After the fall

117 Animals, early humans and mortality

120 Plight of the living dead

122 The quest for immortality

124Earthly remains

126 Dont fear the reaper

7

9

Consciousness 8

Death

Sleep

Self

78 The origin of time79 Times arrow

81 Countdown to the theory of everything

82 The rhythms of life

85 The clock in your head

86 Personal time warps

87 A life without time

88 The dating game

89 Today twice

90 Time travel

91 The ultimate clock

92 The end of time

Time

5Life

6

52 This is your brain on consciousness

55 Higher levels

57 The silent partner

58 Why be conscious?

60 I, robot

107 In your dreams

110 The little sleep

114 Wonder of slumber

96 What are you?

99 When are you?

100Where are you?

103 Why are you?

4


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6| NewScientist: The Collection|The Big Questions

DARRENH

OPES


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R E A L I T YWHEN you woke up this morning, you found the world largely as youleft it. You were still you; the room in which you awoke was the same oneyou went to sleep in. The outside world had not been rearranged. Historywas unchanged and the future remained unknowable. In other words,you woke up to reality. But what is reality? Its surprisingly hard to say.Even dening it is difficult. Whatever reality is, it isnt what it seems...

DEFINING

REALITY

There are two definitions of reality that

are much more successful. The first equates

reality with a world without us, a world

untouched by human desires and intentions.

By this definition, a lot of things we usually

regard as real languages, wars, the financial

crisis are nothing of the sort. Still, it is the

most solid one so far because it removeshuman subjectivity from the picture.

The second equates reality with the most

fundamental things that everything else

depends on. In the material world, molecules

depend on their constituent atoms, atoms

on electrons and a nucleus, which in turn

depends on protons and neutrons, and so

on. In this hierarchy, every level depends on

the one below it, so we might define reality

as made up of whatever entities stand at

the bottom of the chain of dependence, and

thus depend on nothing else.

This definition is even more restrictive

than the world without us since things likeMount Everest would not count as part of

reality; reality is confined to the unknown

foundation on which the entire world

depends. Even so, when we investigate

whether something is real or not, these

final two definitions are what we should

have in mind.

believe in something does not make it real.

Another possible mark of reality we could

focus on is the resistance it puts up: as the

science fiction writer Philip K. Dick put it,

reality is that which, if you stop believing in

it, does not go away. Things we just make up

yield to our wishes and desires, but reality is

stubborn. Just because I believe there is ajam doughnut in front of me doesnt mean

there really is one. But again, this definition

is problematic. Things that we do not want

to regard as real can be stubborn too, as

anyone who has ever been trapped in a

nightmare knows. And some things that are

real, such as stock markets, are not covered

by this definition because if everyone

stopped believing in them, they would

cease to exist.

WHAT DO we actually mean by reality?

A straightforward answer is that it means

everything that appears to our five senses

everything that we can see, smell, touch

and so forth. Yet this answer ignores such

problematic entities as electrons, the

recession and the number 5, which we

cannot sense but which are very real. It also

ignores phantom limbs and illusory smells.

Both can appear vividly real, but we would

like to say that these are not part of reality.

We could tweak the definition by equatingreality with what appears to a sufficiently

large group of people, thereby ruling out

subjective hallucinations. Unfortunately

there are also hallucinations experienced by

large groups, such as a mass delusion

known as koro, mainly observed in South-

East Asia, which involves the belief that

ones genitals are shrinking back into ones

body. Just because sufficiently many people

ByJan Westerhoff

C H A P T E R O N E


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WZ

g

H0

FORCE CARRIERS

DARK

MATTER

DARK

ENERGY

GRAVITY

MASS GIVER

Electromagnetism

The basic ingredients of reality The 4% of the universe we know about...*

UP

DOWN

ELECTRON

ELECTRONNEUTRINO

Q

UARKS

BOSONS

LEPTONS

CHARM

STRANGE

MUON

MUONNEUTRINO

TOP

PHOTON

GLUON

Strong nuclear

Weak nuclear

HIGGS BOSON

BOTTOM

TAU

TAUNEUTRINO

u c t

d se

e

b

...an the %we ont

* for simplicity antiparticles are not shown

IS ANYTHING real? The question seems to

invite only one answer: of course it is. If in

doubt, try kicking a rock.

Leaving aside the question of whether

your senses can be trusted, what are you

actually kicking? When it boils down to it,

not a lot. Science needs remarkably few

ingredients to account for a rock: a handful

of different particles, the forces that govern

their interactions, plus some rules laid down

by quantum mechanics.

This seems like a solid take on reality, but it

quickly starts to feel insubstantial. If you take

a rock apart, youll find that its basic

constituent is atoms perhaps 1000 trillion

trillion of them, depending on the rocks size.

Atoms, of course, are composed of smallersubatomic particles, namely protons and

neutrons themselves built of quarks

and electrons. Otherwise, though, atoms

(and hence rocks) are mostly empty space.

If an atom were scaled up so that its nucleus

was the size of the Earth, the distance to its

closest electrons would be 2.5 times the

distance between the Earth and the sun. In

between is nothing at all. If so much of reality

is built on emptiness, then what gives rocks

and other objects their form and bulk?

Physics has no problem answering this

question: electrons. Quantum rules dictate

that no two electrons can occupy the same

quantum state. The upshot of this is that, no

matter how hard you try, you cannot cram

two atoms together into the same space.

Electrons do all the work when it comes to

the structure of matter we see all around us,

says physicist Sean Carroll at the California

Institute of Technology in Pasadena.Thats not to say the nucleus is

redundant. Most of the mass of an atom

comes from protons and neutrons and

the force binding them together, whichis carried by particles called gluons.

And that, essentially, is that. Electrons,

quarks (mostly of the up and down variety)

and gluons account for most of the ordinary

stuff around us.

But not all. Other basic constituents

of reality exist too 17 in total, which

together comprise the standard model of

particle physics (see illustration, below).

The model also accounts for the mirror

world of antimatter with a complementary

set of antiparticles.

Some pieces of the standard model

are commonplace, such as photons of light

and the various neutrinos streaming

through us from the sun and other sources.

Others, though, do not seem to be part of

everyday reality, including the top and

bottom quarks and the heavy, electron-like

tau particle. On the face of it, they dont

play a role, says Paul Davies of Arizona

State University in Tempe. Deep down,

though, they may all link up.

Thats because the standard model is

more than a roll call of particles. Its

foundations lie in symmetry and group

theory, one example of the mysteriousconnections between reality and

mathematics (see page 10).

The standard model is arguably even

stranger for what it doesnt include. It has

nothing to say about the invisible dark

matter than seems to make up most of the

matter in the universe. Nor does it account

for dark energy. These are serious

omissions when you consider that dark

matter and dark energy together comprise

about 96 per cent of the universe. It is also

totally unclear how the standard model

relates to phenomena that seem to be real,

such as time and gravity.So the standard model is at best a fuzzy

approximation, encompassing some, but

not all, of what seems to comprise physical

reality, plus bits and pieces that do not. Most

physicists would agree that the standard

model is in serious need of an overhaul. It

may be the best model we have of reality,

but it is far from the whole story.

THE BEDROCK

OFITALLOur basic understanding of matter and energy isimpressive, but falls well short of a complete theoryof reality, says Valerie Jamieson


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IS

MATTERREAL?

NOTHING seems more real than theworld of everyday objects, but things arenot as they seem. A set of relatively

simple experiments reveals enormousholes in our intuitive understanding ofphysical reality. Trying to explain whatgoes on leads to some very peculiar andoften highly surprising theories of theworld around us.

Here is a simple example. Take anordinary desk lamp, a few pieces of

Its relatively easy to demonstrate what physicalreality isnt. Understanding what it isis much harder,saysJan Westerhoff

IF IN DOUBTTHAT MATTERIS REAL, TRYKICKING A ROCK

CHRISTOPHEAGOU

cardboard with holes of decreasingsizes, and some sort of projection screensuch as a white wall. If you put a piece ofcardboard between the lamp and the

wall, you will see a bright patch wherethe light passes through the hole in thecardboard. If you now replace thecardboard with pieces containingsmaller and smaller holes, the patch toowill diminish in size. Once we get belowa certain size, however, the pattern onthe wall changes from a small dot to aseries of concentric dark and light rings,rather like an archery target. This is theAiry pattern a characteristic sign of awave being forced through a hole (seeabove left).

In itself, this is not very surprising.

After all, we know that light is a wave, soit should display wave-like behaviour.

But now consider what happens if wechange the set-up of the experiment abit. Instead of a lamp, we use a device


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WHEN Albert Einstein finally completed

his general theory of relativity in 1916,

he looked down at the equations and

discovered an unexpected message: the

universe is expanding.

Einstein didnt believe the physical

universe could shrink or grow, so he ignored

what the equations were telling him.

Thirteen years later, Edwin Hubble found

clear evidence of the universes expansion.

Einstein had missed the opportunity to

make the most dramatic scientific

prediction in history.How did Einsteins equations know

that the universe was expanding when

he did not? If mathematics is nothing more

than a language we use to describe the

world, an invention of the human brain, how

can it possibly churn out anything beyond

what we put in? It is difficult to avoid the

impression that a miracle confronts us here,

wrote physicist Eugene Wigner in his classic

1960 paper The unreasonable effectiveness

of mathematics in the natural sciences.

The prescience of mathematics seems

no less miraculous today. At the Large

Hadron Collider at CERN, near Geneva,Switzerland, physicists recently confirmed

the existence of a particle that was arguably

discovered 48 years ago lurking in the

equations of particle physics.

How is it possible that mathematics

knows about Higgs particles or any other

feature of physical reality? Maybe its

because math isreality, says physicist Brian

Greene of Columbia University in New York.

Perhaps if we dig deep enough, we would

find that physical objects like tables and

chairs are ultimately not made of particles

or strings, but of numbers.

These are very difficult issues, says

philosopher of science James Ladyman of the

University of Bristol, UK, but it might be less

misleading to say that the universe is made

of maths than to say it is made of matter.

Difficult indeed. What does it mean to saythat the universe is made of mathematics?

An obvious starting point is to ask what

mathematics is made of. The late physicistJohn Wheeler said that the basis of all

mathematics is 0 = 0. All mathematical

structures can be derived from something

called the empty set, the set that contains

no elements. Say this set corresponds to

zero; you can then define the number 1 as

the set that contains only the empty set, 2

as the set containing the sets corresponding

to 0 and 1, and so on. Keep nesting the

nothingness like invisible Russian dolls and

eventually all of mathematics appears.

Mathematician Ian Stewart of the University

of Warwick, UK, calls this the dreadful

secret of mathematics: its all based on

nothing. Reality may come down to

mathematics, but mathematics comes

down to nothing at all.

That may be the ultimate clue to

existence after all, a universe made of

nothing doesnt require an explanation.

Indeed, mathematical structures dont

seem to require a physical origin at all.

A dodecahedron was never created, says

The fact that the natural world can be described soprecisely by mathematics is telling us somethingprofound, says Amanda Gefter

IS

EVERYTHINGMADE OFNUMBERS?

DARRENH

OPES


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The Big Questions| NewScientist: The Collection

that shoots out electrons, like thatfound in old-fashioned TV sets; insteadof the wall, we use a plate of glass coatedwith a phosphor that lights up when anelectron strikes it. We can therefore usethis screen to track the places where theelectrons hit. The results are similar:with sufficiently small holes we get anAiry pattern.

This now seems peculiar: electronsare particles located at precise points

and cannot be split. Yet they arebehaving like waves that can smear outacross space, are divisible, and mergeinto one another when they meet.

Perhaps it is not that strange after all.Water consists of molecules, yet itbehaves like a wave. The Airy patternmay just emerge when enough particlescome together, whether they are watermolecules or electrons.

A simple variant of the experimentsshows, however, that this cannot beright. Suppose we reduce the output of

the electron gun to one particle eachminute. The Airy pattern is gone, and allwe see is a small flash every minute.Lets leave this set-up to run for a while,recording each small flash as it occurs.Afterwards, we map the locations of allthe thousands of flashes.

Surprisingly, we do not end up with arandom arrangement of dots, but withthe Airy pattern again. This result isextremely strange. No individualelectron can know where all the earlierand later electrons are going to hit, sothey cannot communicate with each

Max Tegmark of the Massachusetts

Institute of Technology. To be created,

something first has to not exist in space or

time and then exist. A dodecahedron

doesnt exist in space or time at all, he says

it exists independently of them. Space and

time themselves are contained within larger

mathematical structures, he adds. These

structures just exist; they cant be created

or destroyed.

That raises a big question: why is the

universe only made of some of the available

mathematics? Theres a lot of math out

there, Greene says. Today only a tiny sliver

of it has a realisation in the physical world.

Pull any math book off the shelf and most of

the equations in it dont correspond to any

physical object or physical process.

It is true that seemingly arcane and

unphysical mathematics does, sometimes,

turn out to correspond to the real world.

Imaginary numbers, for instance, were once

considered totally deserving of their name,

but are now used to describe the behaviourof elementary particles; non-Euclidean

geometry eventually showed up as gravity.

Even so, these phenomena represent a tiny

slice of all the mathematics out there.

Not so fast, says Tegmark. I believe thatphysical existence and mathematical

existence are the same, so any structure that

exists mathematically is also real, he says.

So what about the mathematics our

universe doesnt use? Other mathematical

structures correspond to other universes,

Tegmark says. He calls this the level 4

multiverse, and it is far stranger than the

multiverses that cosmologists often

discuss. Their common-or-garden

multiverses are governed by the same basic

mathematical rules as our universe, but

Tegmarks level 4 multiverse operates with

completely different mathematics.

All of this sounds bizarre, but the

hypothesis that physical reality is

fundamentally mathematical has passed

every test. If physics hits a roadblock at

which point it turns out that its impossible

to proceed, we might find that nature cant

be captured mathematically, Tegmark says.

But its really remarkable that that hasnt

happened. Galileo said that the book of

nature was written in the language of

mathematics and that was 400 years ago.

If reality isnt, at bottom, mathematics,

what is it? Maybe someday well encounteran alien civilisation and well show them

what weve discovered about the universe,

Greene says. Theyll say, Ah, math. We tried

that. It only takes you so far. Heres the real

thing. What would that be? Its hard to

imagine. Our understanding of fundamental

reality is at an early stage.


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DARRENHOPES

other to create the bullseye pattern.Rather, each electron must havetravelled like a wave through the hole toproduce the characteristic pattern, thenchanged back into a particle to producethe point on the screen. This, of course,is the famous wave-particle duality ofquantum mechanics.

This strange behaviour is shared byany sufficiently small piece of matter,

including electrons, neutrons, photonsand other elementary particles, but notjust by these. Similar effects have beenobserved for objects that are largeenough in principle to be seen undera microscope, such as buckyballs.

In order to explain the peculiarbehaviour of such objects, physicistsassociate a wave function with each ofthem. Despite the fact that these waveshave the usual properties of morefamiliar waves such as sound or waterwaves, including amplitude (how far

up or down it deviates from the reststate), phase (at what point in a cycle thewave is), and interference (so that upand down phases of waves meetingeach other cancel out), what they arewaves inis not at all transparent.Einstein aptly spoke of a phantomfield as their medium.

For a wave in an ordinary mediumsuch as water, we can calculate itsenergy at any one point by taking thesquare of its amplitude. Wave functions,however, carry no energy. Instead, thesquare of their amplitude at any given

point gives us the probability ofobserving the particle if a detectorsuch as the phosphor-coated screenis placed there.

Clearly, the point where an objectswitches from being a probability wave,with its potential existence smeared outacross space, and becomes an actual,spatially localised object is cruciallyimportant to understanding whethermatter is real. What exactly happenswhen the wave function collapses when among the countless possibilitieswhere the particle could be at any

moment, one is chosen, while all theothers are rejected?

First of all, we have to ask ourselveswhen this choice is made. In theexample described above, it seems tohappen just before the flash on the

phosphor screen. At this moment,a measurement of the electronsposition was made by a piece ofphosphor glowing as the particle struckit, so there must have been an electronthere, and not just a probability wave.

But assume we cannot be in the lab toobserve the experiment, so we point acamera at the phosphor screen and havethe result sent via a satellite link to acomputer on our desktop. In this case,the flash of light emitted from thephosphor screen has to travel to thecamera recording it, and the process is


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WHATEVER kind of reality you think

youre living in, youre probably wrong. The

universe is a computer, and everything that

goes on in it can be explained in terms of

information processing.

The connection between reality and

computing may not be immediately obvious,

but strip away the layers and that is exactly

what some researchers think we find. We

think of the world as made up of particles

held together by forces, for instance, but

quantum theory tells us that these are just

a mess of fields we can only properly

describe by invoking the mathematics of

quantum physics.

Thats where the computer comes in,at least if you think of it in conceptual terms

as something that processes information

rather than as a boxy machine on your desk.

Quantum physics is almost phrased in terms

of information processing, says Vlatko

Vedral of the University of Oxford. Its

suggestive that you will find information

processing at the root of everything.

Information certainly has a special place

in quantum theory. The famous uncertainty

principle which states that you cant

simultaneously know the momentum and

position of a particle comes down to

information. As does entanglement, wherequantum objects share properties and

exchange information irrespective of the

physical distance between them.

In fact, every process in the universe

can be reduced to interactions between

particles that produce binary answers: yes or

no, here or there, up or down. That means

nature, at its most fundamental level, is

simply the flipping of binary digits or bits, just

like a computer. The result of the myriad bit

flips is manifest in what we perceive as the

IFINFORMATIONTHENUNIVERSE

ongoing arrangement, rearrangement and

interaction of atoms in other words, reality.

According to Ed Fredkin of Carnegie

Mellon University and the Massachusetts

Institute of Technology, if we could dig into

this process we would find that the universe

follows just one law, a single information-

processing rule that is all you need to build a

cosmos. In Fredkins view, this would be

some form of if then procedure; the kind

of rule used in traditional computing to

manipulate the bits held by transistors on a

chip and operate the logic gates, but this

time applied to the bits of the universe.Vedral and others think its a little more

complex than that. Because we can reduce

everything in the universe to entities that

follow the laws of quantum physics, the

universe must be a quantum computer rather

than the classical type we are familiar with.

One of the attractions of this idea is that it

can supply an answer to the question why is

there something rather than nothing?. The

randomness inherent in quantum mechanics

means that quantum information and by

extension, a universe can spontaneously

come into being, Vedral says.

For all these theoretical ideas, proving

that the universe is a quantum computer is

a difficult task. Even so, there is one

observation that supports the idea that the

universe is fundamentally composed of

information. In 2008, the GEO600

gravitational wave detector in Hannover,

Germany, picked up an anomalous signal

suggesting that space-time is pixelated.

This is exactly what would be expected in a

holographic universe, where 3D reality is

actually a projection of information encoded

on the two-dimensional surface of the

boundary of the universe.

This bizarre idea arose from an argument

over black holes. One of the fundamental

tenets of physics is that information cannot

be destroyed, but a black hole appears to

violate this by swallowing things that

contain information, then gradually

evaporating away. What happens to that

information was the subject of a long

debate between Stephen Hawking and

several of his peers. In the end, Hawking

lost the debate, conceding that theinformation is imprinted on the event

horizon that defines the black holes

boundary and escapes as the black hole

evaporates. This led theoretical physicists

Leonard Susskind and Gerard t Hooft to

propose that the entire universe could also

hold information at its boundary with the

consequence that our reality could be the

projection of that information into the space

within the boundary (see page 23). If this

conjecture is true, reality is like the image of

Princess Leia projected by R2D2 inStar

Wars: a hologram.

THE UNIVERSE MUSTBE A QUANTUMCOMPUTER

Find the idea of a universe made of mathematicshard to swallow? Then try this on for size,

says Michael Brooks


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repeated: like the electrons, light alsotravels as a wave and arrives as aparticle. What reason is there to believethat the switch from probability waveto particle actually occurred on thephosphor screen, and not in thecamera?

At first, it seemed as if the phosphorscreen was the measuring instrument,

and the electron was the thing beingmeasured. But now the measuringdevice is the camera and the phosphorscreen is part of what is measured.Given that any physical objecttransmitting the measurement we canadd on to this sequence the camera,the computer, our eyes, our brain ismade up of particles with the sameproperties as the electron, how can wedetermine any particular step at whichto place the cut between what ismeasured and what is doing the

measuring?This ever-expanding chain is calledthe von Neumann chain, after thephysicist and mathematician John vonNeumann. One of his PrincetonUniversity colleagues, Eugene Wigner,made a suggestion as to where to makethe cut. As we follow the von Neumannchain upwards, the first entity weencounter that is not made up in anystraightforward fashion out of pieces ofmatter is the consciousness of theobserver. We might therefore want tosay that when consciousness enters the

picture, the wave function collapsesand the probability wave turns intoa particle.

The idea that consciousness bringseveryday reality into existence is, ofcourse, deeply strange; perhaps it islittle wonder that it is a minorityviewpoint.

There is another way of interpretingthe measurement problem that doesnot involve consciousness though ithas peculiar ramifications of its own.But for now lets explore Wigners ideain more depth.

If a conscious observer does notcollapse the wave function, curiousconsequences follow. As more and moreobjects get sucked into the vortex of von

Neumanns chain by changing frombeing a measuring instrument to beingpart of what is measured, the spread-out structure of the probability wavebecomes a property of these objects too.The superposed nature of theelectron its ability to be at variousplaces at once now also affects themeasuring instruments.

It has been verified experimentallythat not just the unobservably small,but objects large enough to be seenunder a microscope, such as a60-micrometre-long metal strip, can

exhibit such superposition behaviour.Of course, we cant look through amicroscope and see the metal stripbeing at two places at once, as thiswould immediately collapse the wavefunction. Yet it is clear that theindeterminacy we found at the atomiclevel can spread to the macro level.

Yet if we accept that the wave functionmust collapse as soon as consciousnessenters the measurement, theconsequences are even more curious. Ifwe decide to break off the chain at this

point, it follows that, according to one ofour definitions of reality, matter cannotbe regarded as real. If consciousness isrequired to turn ghostly probabilitywaves into things that are more or lesslike the objects we meet in everyday life,how can we say that matter is whatwould be there anyway, whether or nothuman minds were around?

But perhaps this is a bit too hasty.Even if we agree with the idea thatconsciousness is required to break thechain, all that follows is that thedynamic attributes of matter such as

position, momentum and spinorientation are mind-dependent. Itdoes not follow that its static attributes,including mass and charge, aredependent on in this. The staticattributes are there whether welook or not.

Nevertheless, we have to ask ourselveswhether redefining matter as a set ofstatic attributes preserves enough ofits content to allow us to regard matteras real. In a world without minds, therewould still be attributes such as massand charge, but things would not be at

any particular location or travel in anyparticular direction. Such a world hasvirtually nothing in common with theworld as it appears to us. Werner

Heisenberg observed that: theontology of materialism rested uponthe illusion that the kind of existence,the direct actuality of the world aroundus, can be extrapolated into the atomicrange. This extrapolation, however, isimpossible Atoms are not things.

It seems that the best we are going toget at this point is the claim that somethings are there independent ofwhether we, as human observers, arethere, even though they might havevery little to do with our ordinaryunderstanding of matter.

Does our understanding of the realityof matter change if we choose the otherstrong definition of reality not by whais there anyway, but by what providesthe foundation for everything else?

In order to answer this question, wehave to look at the key scientific notionof a reductive explanation. Much of thepower of scientific theories derives fromthe insight that we can use a theory thatapplies to a certain set of objects toexplain the behaviour of a quitedifferent set of objects. We therefore

dont need a separate set of laws andprinciples to explain the second set.A good example is the way in which

theories from physics and chemistry,dealing with inanimate matter, can beused to explain biological processes.There is no need to postulate a specialphysics or a special chemistry to explainan organisms metabolism, how itprocreates, how its genetic informationis passed on, or how it ages and dies. Thebehaviour of the cells that make up theorganism can be accounted for in termsof the nucleus, mitochondria and other

subcellular entities, which can in turn


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physical reality?

This is the central question in quantum

mechanics, and has spawned a plethora of

proposals, or interpretations. The most

popular is the Copenhagen interpretation,

which says nothing is real until it is observed,

or measured. Observing a wave function

causes the superposition to collapse.

However, Copenhagen says nothing about

what exactly constitutes an observation.

John von Neumann broke this silence and

suggested that observation is the action of a

conscious mind. Its an idea also put forwardby Max Planck, the founder of quantum

theory, who said in 1931, I regard

consciousness as fundamental. I regard

matter as derivative from consciousness.

DOESCONSCIOUSNESSCREATEREALITY? That argument relies on the view thatthere is something special about

consciousness, especially human

consciousness. Von Neumann argued that

everything in the universe that is subject to

the laws of quantum physics creates one

vast quantum superposition. But the

conscious mind is somehow different. It is

thus able to select out one of the quantum

possibilities on offer, making it real to that

mind, at least.

Henry Stapp of the Lawrence Berkeley

National Laboratory in California is one of

the few physicists that still subscribe to this

notion: we are participating observers

whose minds cause the collapse of

superpositions, he says. Before human

consciousness appeared, there existed a

multiverse of potential universes, Stapp

says. The emergence of a conscious mind in

one of these potential universes, ours, gives

it a special status: reality.

There are many objectors. One problem is

that many of the phenomena involved arepoorly understood. Theres a big question

in philosophy about whether consciousness

actually exists, says Matthew Donald, a

philosopher of physics at the University of

Cambridge. When you add on quantum

mechanics it all gets a bit confused.

Donald prefers an interpretation that is

arguably even more bizarre: many minds.

This idea related to the many worlds

interpretation of quantum theory, which has

each outcome of a quantum decision happen

in a different universe argues that an

individual observing a quantum system sees

all the many states, but each in a differentmind. These minds all arise from the physical

substance of the brain, and share a past and

a future, but cannot communicate with each

other about the present.

Though it sounds hard to swallow, this

and other approaches to understanding the

role of the mind in our perception of reality

are all worthy of attention, Donald reckons.

I take them very seriously, he says.

DESCARTES might have been on to

something with I think therefore I am, but

surely I think therefore you are is going a

bit far? Not for some of the brightest minds

of 20th-century physics as they wrestled

mightily with the strange implications of

the quantum world.

According to prevailing wisdom, a

quantum particle such as an electron or

photon can only be properly described as a

mathematical entity known as a wavefunction. Wave functions can exist as

superpositions of many states at once.

A photon, for instance, can circulate in two

different directions around an optical fibre;

or an electron can simultaneously spin

clockwise and anticlockwise or be in two

positions at once.

When any attempt is made to observe

these simultaneous existences, however,

something odd happens: we see only one.

How do many possibilities become oneERICHHARTMANN/MAGNUM

If a tree falls in the forest and theres nobody there,maybe there isnt even a forest, says Michael Brooks


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be explained in terms of chemicalreactions based on the behaviour ofmolecules and the atoms that composethem. For this reason, explanations ofbiological processes can be said to be

reducible to chemical and ultimately tophysical ones.

If we pursue a reductive explanationfor the phenomena around us, a firststep is to reduce statements about themedium-sized goods that surround us bricks, brains, bees, bills and bacteria to statements about fundamentalmaterial objects, such as molecules. Wethen realise everything about thesethings can be explained in terms oftheir constituents, namely their atoms.Atoms, of course, have parts as well, and

we are now well on our way through therealm of ever smaller subatomicparticles, perhaps (if string theory iscorrect) all the way down to vibratingstrings of pure energy. So far we have notreached the most fundamental objects.In fact, there is not even an agreementthat there are any such objects.

Yet this is no reason to stop ourreductionist explanation here, since wecan always understand the most basicphysical objects in terms of where theyare in space and time. Instead of talkingabout a certain particle that exists at

such-and-such a place for such-and-such a period of time, we can simplyreduce this to talk about a certain regionin space that is occupied between twodifferent times.

We can go even more fundamental.If we take an arbitrary fixed point inspace, and a stable unit of spatialdistance, we can specify any other pointin space by three coordinates. Thesesimply tell us to go so many units up ordown, so many units left or right, and somany units back or forth. We can do thesame with points in time. We now have

IT IS DIFFICULTTO REFUTE THE IDEATHAT CONSCIOUSNESSIS ALL THERE IS

TOSHIOKISHIYAMA


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a way of expressing points in space-time as sets of four numbers, x, y, z andt, where x, y, and z represent the threespatial dimensions and t the time

dimension. In this way, reality can beboiled down to numbers.

And this opens the door to somethingyet more fundamental. Mathematicianshave found a way of reducing numbersto something even more basic: sets. Todo this, they replace the number 0 withthe empty set, the number 1 with the setthat contains just the empty set, and soon (see page 10). All the properties ofnumbers also hold for all these ersatznumbers made from sets. It seems as ifwe have now reduced all of the materialworld around us to an array of sets.

For this reason, it is important toknow what these mathematical objectscalled sets really are. There are twoviews of mathematical objects that areimportant in this context. First, there isthe view of them as Platonic objects.This means that mathematical objectsare unlike all other objects we encounter.They are not made of matter, they donot exist in space or time, do notchange, cannot be created or destroyed,and could not have failed to exist.According to the Platonic understanding,

mathematical objects exist in a thirdrealm, distinct from the world ofmatter, on the one hand, and the worldof mental entities, such as perceptions,thoughts and feelings, on the other.

Second, we can understandmathematical objects as fundamentallymental in nature. They are of the samekind as the other things that passthrough our mind: thoughts and plans,concepts and ideas. They are not whollysubjective; other people can have the

WKN

holds no philosophical water. As Descartes

pointed out a century earlier, it is

impossible to know we are not dreaming.

Nor has anyone had much luck making

sense of dualism the idea that mind and

matter are distinct. One response is that

there is only matter, making the mind an

illusion that arises from neurons doing their

thing. The opposite position is

panpsychism, which attributes mental

properties to all matter. As the

astrophysicist Arthur Eddington expressed

it in 1928: the stuff of the world is

mind-stuff... not altogether foreign to thefeelings in our consciousness.

Quite separately, rigorous logicians such

as Harvards Willard Van Orman Quine

abandoned the search for a foundation of

reality and took coherentist positions. Let

go of the notion of a pyramid of knowledge,

they argued: think instead of a raft built out

of our beliefs, a seaweedy web of

statements about perceptions and

statements about statements, not

grounded in anything but hanging

together and solid enough to set sail upon.

Or even, possibly, tobea universe.

This idea is circular, and its cheating, saycritics of a more foundationist bent. It leads

back to the suspicion that there actually is

no reality independent of our observations.

But if there is how can we know?

PHILOSOPHERS are not being rude

when they describe the approach most of

us take as naive realism. After all, when they

cross the street on the way to work, they

tend to accept implicitly as we all do

that there is an external reality that exists

independently of our observations of it.

But at work, they have to ask: if there is,

how can we know?

In other words, the question what

exists? reduces, for what in philosophypasses for practical purposes, to questions

such as what do we mean by know?

Plato had a go at it 2400 years ago,

defining knowledge as justified true

belief. But testing the justification or the

truth of beliefs traces back to our

perceptions, and we know these can

deceive us.

Two millennia later, Ren Descartes

decided to work out what he was sure he

knew. Legend has it that he climbed into a

large stove to do so in warmth and solitude.

He emerged declaring that the only thing he

knew was that there was something thatwas doubting everything.

The logical conclusion of Descartess

doubt is solipsism, the conviction that ones

own consciousness is all there is. Its an idea

that is difficult to refute.

Samuel Johnsons notoriously bluff

riposte to the questioning of the reality of

objects I refute it thus!, kicking a stone

Of course, reality could all be an illusion, butproving it one way or the other is surprisinglydifficult, saysMike Holderness


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very same mathematical object in theirminds as we have in ours, so that whenwe both talk about the Pythagoreantheorem, we are talking about the samething. Still, they do not exist except in

the minds in which they occur.Either of these understandings leads

to a curious result. If the bottom level ofthe world consists of sets, and if sets arenot material but are instead somePlatonic entities, material objects havecompletely disappeared from view andcannot be real in the sense ofconstituting a fundamental basis of allexistence. If we follow scientificreductionism all the way down, we endup with stuff that certainly does notlook like tiny pebbles or billiard balls,

not even like strings vibrating in amultidimensional space, but more likewhat pure mathematics deals with.

Of course, the Platonistic view ofmathematical objects is hardlyuncontroversial, and many people findit hard to get any clear idea of howobjects could exist outside of space andtime. But if we take mathematicalobjects to be mental in nature, we endup with an even stranger scenario.

The scientific reductionist sets out toreduce the human mind to the activityof the brain, the brain to an assembly of

interacting cells, the cells to molecules,the molecules to atoms, the atoms tosubatomic particles, the subatomicparticles to collections of space-time

points, the collections of space-timepoints to sets of numbers, and the setsof numbers to pure sets. But at the veryend of this reduction, we now seem toloop right back to where we came from:to the mental entities.

We encounter a similar curious loopin the most influential way ofunderstanding quantum mechanics,the Copenhagen interpretation.Unlike Wigners consciousness-basedinterpretation, this does not assume thewave function collapses when aconscious mind observes the outcome

of some experiment. Instead, it happenswhen the system to be measured (theelectron) interacts with the measuringdevice (the phosphor screen). For thisreason, it has to be assumed that thephosphor screen will not itself exhibitthe peculiar quantum behaviour shownby the electron.

In the Copenhagen interpretation,then, things and processes describablein terms of familiar classical conceptsare the foundation of any physicalinterpretation. And this is where the

circularity comes in. We analyse theeveryday world of medium-sizedmaterial things in terms of smaller andsmaller constituents until we deal withparts that are so small that quantumeffects become relevant for describingthem. But when it comes to spelling outwhat is really going on when a wavefunction collapses into an electronhitting a phosphor screen, we dontground our explanation in some yetmore minute micro-level structures;we ground it in terms of readings madeby non-quantum material things.

What this means is that instead ofgoing further down, we instead jumpright back up to the level of concretephenomena of sensory perception,namely measuring devices such asphosphor screens and cameras. Oncemore, we are in a situation where wecannot say that the world of quantumobjects is fundamental. Nor can we saythat the world of measuring devices isfundamental since these devices arethemselves nothing but largeconglomerations of quantum objects.

We therefore have a circle of things

depending on each other, even though,unlike in the previous case, mentalobjects are no longer part of thiscircle. As a result, neither the phosphorscreen nor the minute electron can beregarded as real in any fundamentalsense, since neither constitutes a classof objects that everything depends on.What we thought we should take to bethe most fundamental turns out toinvolve essentially what we regardedas the least fundamental.

In our search for foundations, we

have gone round in a circle, from themind, via various components ofmatter, back to the mind or, in thecase of the Copenhagen interpretation,from the macroscopic to themicroscopic, and then back to themacroscopic. But this just means thatnothing is fundamental, in the sameway there is no first or last stop onLondon Undergrounds Circle Line. Themoral to draw from the reductionistscenario seems to be that either what isfundamental is not material, or thatnothing at all is fundamental.

MATERIAL OBJECTS

DISAPPEAR FROMVIEW AND CANNOTBE REAL


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JIRAYUKOO/AGENCYRUSH.C

OM

XTIts lucky youre here13.7 billion years ago, theuniverse was born in a cosmicreball. Roughly 10 billion years

later, the planet we call Earth gavebirth to life, which eventually ledto you. The probability of thatsequence of events is absolutelyminuscule, and yet it still happened.

Take a step back from theunlikeliness of your own personalexistence and things get even moremind-boggling. Why does theuniverse exist at all? Why is itne-tuned to human life? Why doesit seem to be telling us that thereare other universes out there,even other yous?

Confronting these mysteries ofexistence can lead to bizarreconclusions, from the possibility

that the universe is a hologramto the near-certainty that you area zombie. Enjoy the ride.

C H A P T E R T W O


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20| NewScientist:The Collection|The Big Questions

Why is theresomething rather

than nothing?

AS DOUGLAS ADAMS once wrote:The universe is big. Really big. And yetif our theory of the big bang is right, theuniverse was once a lot smaller. Indeed,at one point it was non-existent. Around13.7 billion years ago time and spacespontaneously sprang from the void.How did that happen?

Or to put it another way: why

does anything exist at all? Its a bigquestion, perhaps the biggest. Theidea that the universe simply appearedout of nothing is difficult enough;trying to conceive of nothingness isperhaps even harder.

It is also a very reasonable questionto ask from a scientific perspective.After all, some basic physics suggeststhat you and the rest of the universe areoverwhelmingly unlikely to exist. Thesecond law of thermodynamics, thatmost existentially resonant of physicallaws, says that disorder, or entropy,

always tends to increase. Entropymeasures the number of ways youcan rearrange a systems componewithout changing its overallappearance. The molecules in a hotgas, for example, can be arranged imany different ways to create the soverall temperature and pressure,making the gas a high-entropy syst

In contrast, you cant rearrange themolecules of a living thing very muwithout turning it into a non-livingthing, so you are a low-entropy sys

By the same logic, nothingness ihighest entropy state around youcan shuffle it around all you want ait still looks like nothing.

Given this law, it is hard to seehow nothing could ever be turnedinto something, let alone somethinas big as a universe. But entropy isonly part of the story. The otherconsideration is symmetry a qua

JIRAYUKOO/AGENCYRUSH.C

OM


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Perhapsthe big bangwas justnothingness

doing whatcomesnaturally

that appears to exert profoundinfluence on the physical universewherever it crops up. Nothingness isvery symmetrical indeed. Theresno telling one part from another, so ithas total symmetry, says physicistFrank Wilczek of the MassachusettsInstitute of Technology.

And as physicists have learned

over the past few decades, symmetriesare made to be broken. Wilczeksown speciality is quantumchromodynamics, the theory thatdescribes how quarks behave deepwithin atomic nuclei. It tells us thatnothingness is a precarious state ofaffairs. You can form a state that hasno quarks and antiquarks in it, and itstotally unstable, says Wilczek. Itspontaneously starts producing quark-antiquark pairs. The perfect symmetryof nothingness is broken. That leads toan unexpected conclusion, says Victor

coalesce and life to evolve into bipedwho ask how something came fromnothing, its total energy must beextraordinarily low.

That fits with the generally

accepted view of the universes earlymoments, which sees space-timeundergoing a brief burst of expansioimmediately after the big bang. Thisheady period, known as inflation,flooded the universe with energy. Buaccording to Einsteins general theorof relativity, more space-time alsomeans more gravity. Gravitysattractive pull represents negativeenergy that can cancel out inflationpositive energy essentiallyconstructing a cosmos for nothing.

I like to say that the universe is theultimate free lunch, says Alan Gutha cosmologist at MIT who came upwith the inflation theory in 1981.

Physicists used to worry thatcreating something from nothingwould violate all sorts of physicallaws such as the conservation ofenergy. But if there is zero overallenergy to conserve, the problemevaporates and a universe that simpopped out of nothing becomes notjust plausible, but probable. Maybea better way of saying it is that

something isnothing, says Guth.None of this really gets us off the

hook, however. Our understandingof creation relies on the validity ofthe laws of physics, particularlyquantum uncertainty. But thatimplies that the laws of physics weresomehow encoded into the fabric ofour universe before it existed. How cphysical laws exist outside of spaceand time and without a cause of theiown? Or, to put it another way, why ithere something rather than nothinAmanda Gefter

Stenger, a philosopher at the Universityof Colorado in Boulder: despiteentropy, something is the morenatural state than nothing.

According to quantum theory,

there is no state of emptiness, agreesFrank Close of the University of Oxford.Emptiness would have precisely zeroenergy, far too exacting a requirementfor the uncertain quantum world.Instead, a vacuum is actually filled witha roiling broth of particles that pop inand out of existence. In that sense thismagazine, you, me, the moon andeverything else in our universe are justexcitations of the quantum vacuum.

Before the big bang

Might something similar account forthe origin of the universe itself? Quiteplausibly, says Wilczek. There is nobarrier between nothing and a richuniverse full of matter, he says. Perhapsthe big bang was just nothingnessdoing what comes naturally.

This, of course, raises the questionof what came before the big bang, andhow long it lasted. Unfortunately atthis point basic ideas begin to fail us;the concept before becomesmeaningless. In the words of Stephen

Hawking, its like asking what is northof the north pole.

Even so, there is an even moremind-blowing consequence of theidea that something can come fromnothing: perhaps nothingness itselfcannot exist.

Heres why. Quantum uncertaintyallows a trade-off between time andenergy, so something that lasts a longtime must have little energy. To explainhow our universe has lasted for thebillions of years that it has takengalaxies to form, solar systems to


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22| NewScientist:The Collection| The Big Questions

Are we alone?HAVE you ever looked up at the night skyand wondered if somebody, or something,

is looking back? If perhaps somewhere out

there, the mysterious spark we call life has

flickered into existence?

Intuitively, it feels as if we cant be alone.

For every one of the 2000 stars you can see

with your naked eye, there are another

50 million in our galaxy, which is one of

100 billion galaxies. In other words, the star

we orbit is just one of 10,000 billion billion in

the cosmos. Surely there is another blue dot

out there a home to intelligent life like us?

The simple fact is, we dont know.

One way to estimate the number of

intelligent civilisations was devised by

astronomer Frank Drake. His equation takes

into account the rate of star formation, the

fraction of those stars with planets and

the likelihood that life, intelligent life, and

intelligent creatures capable of

communicating with us, will arise.

It is now possible to put numbers on

some of those factors. About 20 stars are

born in the Milky Way every year, and we

have spotted more than 1000 planets

around stars other than the sun. Estimates

suggest that there are 11 billion Earth-likeplanets orbiting sunlike stars in our galaxy.

But estimating the biological factors is

little more than guesswork. We know that

life is incredibly adaptable once it emerges,

but not how good it is at getting started in

the first place.

Unique planet

Some astronomers believe life is almost

inevitable on any habitable planet. Others

suspect simple life is common, but intelligent

life exceedingly rare. A few believe that our

planet is unique. Life may or may not formeasily, says physicist Paul Davies of Arizona

State University in Tempe. Were completely

in the dark.

So much for equations. What about

evidence? Finding life on Mars probably

wont help, as it would very likely share

its origin with Earthlings. Impacts have

undoubtedly conveyed microorganisms back

and forth, says Davies. Mars and Earth are

not independent ecosystems.

Discovering life on Titan would be more

revealing. Titan is the only other place in

the solar system with liquid on its surface

albeit lakes of ethane. We are starting tthink that if there is life on Titan it woul

have a separate origin, says Dirk Schulz

Makuch at Washington State University

in Pullman. If we can find a separate

origin we can say OK, theres a lot of life

in the universe.

Discovering alien microbes in our sola

system would be some sort of proof tha

we are not alone, but what we really wa

to know is whether there is another

intelligence out there. For more than

50 years astronomers have swept the s

with radio telescopes for any hint of a

message. So far, nothing.

But that doesnt mean ET isnt there.

just might not know were here. The on

evidence of our existence that reaches

beyond the solar system are radio signa

and light from our cities. Weve only be

broadcasting powerful radio signals sin

the second world war, says Seth Shost

of the SETI Institute in Mountain View,

California. So our calling card has leaked

70 light years into space, a drop in the o

If the Milky Way was the size of London

Earth was at the base of Nelsons Colum

our radio signals would still not have lefTrafalgar Square.

Its probably safe to say that even if

the local galaxy is choc-a-bloc with alien

none of them know that Homo sapiens

here, says Shostak. That also works in

reverse. Given the size of the universe a

the speed of light, most stars and plane

are simply out of range.

It is also possible that intelligent life i

separated from us by time. After all, hum

intelligence has only existed for a minu

fraction of Earths history and may just

fleeting phase. It may be too much of a

stretch to hope that a nearby planet noonly harbours intelligent life, but that it

so right now.

But lets say we did make contact wit

aliens. How would we react? NASA has

plans, and most religions claim they wo

be able to absorb the idea, but the bott

line is we wont know until it happens.

Most likely well never find out. Even

Earth is not the only planet with intellig

life, we appear destined to live out our e

existence as if it were but with a nagg

feeling that it cant be. Hows that for existe

uncertainty? Valerie Jamieson

HD 156668

HIP 12961

Gleise 179

Gleise 317

Gleise 581

Gleise 876

Epsilon Eridani

Proxima Centauri(nearest star;

no exoplanet)

Gleise 676

Alpha Arietis

HIP 79431

HD 114783

521 Pegasi

UpsilonAndromedae

Iota Horologii

Lambda2Fornacis

Fomalhaut

61 Virginis

The Wire(2002)

Big Brother(2000)

The X-Files(1993)

The Simpsons(1989)

Star Trek(1966)

Kennedy vs Nixonpresidential debate(1960)

End of secondworld war (1945)

First commercialcolour TV;

I Love Lucy(1951)

BBC s rstregular public TVbroadcasts in the

UK (1936)

First experimentalTV broadcasts (1925)

First publicly accessibleTV broadcast in US(1928)

The Beatles onThe Ed Sullivan Show (1964)

Challengerdisaster (1986)

Apollo 11moon landing

(1969)

MTV (1981)

BROADCASTING TO THE STARSTV signals from Earth are travelling outwards at light speed.If aliens are out there, here's what is premiering now

90

80

70

6

50

4

40

2

2

1

Star withexoplanet

TV broadcast

Number of light years away

OUR SOLARSYSTEM

MILKY WAY100,000 ly across

OUR TVFOOTPRINT

160 ly across


25/132


TAKE a look around you. The walls, the chair

youre sitting in, your own body they all

seem real and solid. Yet there is a possibilitythat everything we see in the universe

including you and me may be nothing

more than a hologram.

It sounds preposterous, yet there is

already some evidence that it may be true,

and we could know for sure within a couple

of years. If it does turn out to be the case, it

would turn our common-sense conception

of reality inside out.

The idea has a long history, stemming

from an apparent paradox posed by

Stephen Hawkings work in the 1970s. He

discovered that black holes slowly radiate

their mass away. This Hawking radiation

appears to carry no information, however,raising the question of what happens to

the information that described the original

star once the black hole evaporates. It is

a cornerstone of physics that information

cannot be destroyed.

In 1972 Jacob Bekenstein at the Hebrew

University of Jerusalem, Israel, showed

that the information content of a black hole

is proportional to the two-dimensional

surface area of its event horizon the point

of no return for in-falling light or matter.

Later, string theorists managed to show

how the original stars information could b

encoded in tiny lumps and bumps on the

event horizon, which would then imprint on the Hawking radiation departing the

black hole.

This solved the paradox, but theoretica

physicists Leonard Susskind and Gerard

t Hooft decided to take the idea a step

further: if a three-dimensional star could

be encoded on a black holes 2D event

horizon, maybe the same could be true

of the whole universe. The universe does

after all, have a horizon 42 billion light ye

away, beyond which point light would not

have had time to reach us since the big

The entire 3Duniverse weexperiencemay beencoded ina 2D surface

Am I a hologram?


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24| NewScientist:The Collection| The Big QuestionsJIRAYUK

OO

bang. Susskind and t Hooft suggested

that this 2D surface may encode the

entire 3D universe that we experience

much like the 3D hologram that is

projected from a credit card.It sounds crazy, but we have already

seen a sign that it may be true. Theoretical

physicists have long suspected that

space-time is pixelated, or grainy. Since

a 2D surface cannot store sufficient

information to render a 3D object

perfectly, these pixels would be bigger in

a hologram. Being in the [holographic]

universe is like being in a 3D movie, says

Craig Hogan of Fermilab in Batavia, Illinois.

On a large scale, it looks smooth and

three-dimensional, but if you get close

to the screen, you can tell that it is flat

and pixelated.

Quantum fluctuation

A few years ago Hogan looked at readings

from an exquisitely sensitive motion-

detector in Hannover, Germany, which

was built to detect gravitational waves

ripples in the fabric of space-time. The

GEO600 experiment has yet to find one,

but in 2008 an unexpected jitter left the

team scratching their heads, until Hogan

suggested that it might arise from

quantum fluctuations due to thegraininess of space-time. By rights, these

should be far too small to detect, so the

fact that they are big enough to show

up on GEO600s readings is tentative

supporting evidence that the universe

really is a hologram, he claimed.

Bekenstein is cautious: The

holographic idea is only a hypothesis,

supported by some special cases, he says.

Further evidence may come from a

recently completed instrument at

Fermilab called the Holometer, which will

make the first direct measure of the

graininess of space-time.A positive result would challenge

every assumption we have about the

world we live in. It would show that

everything is a projection of something

occurring on a flat surface billions of light

years away from where we perceive

ourselves to be. As yet we have no idea

what that something might be, or how it

could manifest itself in the world we

know. Maybe it would make no difference

to the way we live our lives, but that

seems unlikely. Marcus Chown

Why me?THINK for a moment about a time

before you were born. Where were

Now think ahead to a time after yo

death. Where will you be? The brut

answer is: nowhere. Your life is a br

foray on Earth that started one dayno reason and will inevitably end.

But what a foray. Like the whole

universe, your consciousness popp

into existence out of nothingness a

has evolved into a rich and complex

entity full of wonder and mystery.

Contemplating this leads to a ho

of mind-boggling questions. What

the odds of my consciousness exis

at all? How can such a thing emerg

from nothingness? Is there any

possibility of it surviving my death

And what is consciousness anyway


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Answering these questions isincredibly difficult. PhilosopherThomas Nagel once asked, What is itlike to be a bat? Your response mightbe to imagine flying around in the

dark, seeing the world in the echoesof high-frequency sounds. But thatisnt the answer Nagel was looking for.He wanted to emphasise that there isno way of knowing what it is like for abat to feel like a bat. That, in essence,is the conundrum of consciousness.

Neuroscientists and philosopherswho study consciousness fall into twobroad camps. One thinks thatconsciousness is an emergent propertyof the brain and that once we fullyunderstand the intricate workings ofneuronal activity, consciousness will be

active when we are conscious ofsomething and quiet when we are not.For example, Stanislas Dehaene of theFrench National Institute of Health andMedical Research in Gif sur Yvette and

colleagues have identified such regionsin our frontal and parietal lobes.

Consciousness explained

This is consistent with a theory ofconsciousness proposed by BernardBaars of the Neuroscience Institute inCalifornia. He posited that most non-conscious experiences are processed inspecialised local regions of the brainsuch as the visual cortex. We onlybecome conscious of this activity whenthe information is broadcast to a

network of neurons called the globalworkspace perhaps the regionspinpointed by Dehaene.

But others believe the theory is nottelling the whole story. Does globalworkspace theory really explainconsciousness, or just the ability toreport about consciousness? asks Seth.

Even so, the idea that consciousnessseems to be an emergent property ofthe brain can take us somewhere. Forexample, it makes the odds of yourown consciousness existing the same

as the odds of you being born at all,which is to say, very small. Just think ofthat next time you suffer angst aboutyour impending return to nothingness.

As for whether individualconsciousness can continue afterdeath, it is extremely unlikely thatthere would be any form of self-consciousness after the physical braindecays, says philosopher ThomasMetzinger of the Johannes GutenbergUniversity in Mainz, Germany.

Extremely unlikely, but notimpossible. Giuilio Tononi of the

University of Wisconsin-Madisonargues that consciousness is theoutcome of how complex matter,including the brain, integratesinformation. According to Tononistheory, if one could build a device ora system that integrated informationexactly the same way as a living brain,it would generate the same consciousexperiences, says Seth. Such a machinemight allow your consciousness tosurvive death. But it would stillnot know what it is like to be a bat.Anil Ananthaswamy

Once weunderstandthe intricateworkings ofthe brain,conscious

experiencewill be laid

bare

laid bare. The other doubts it willbe that simple. They agree thatconsciousness emerges from thebrain, but argue that Nagels questionwill always remain unanswered:

knowing every detail of a bats braincannot tell us what it is like to be a bat.This is often called the hard problemof consciousness, and seemsscientifically intractable for now.

Meanwhile, there are way toomany so-called easy problems toworry about, says Anil Seth of theUniversity of Sussex in Brighton, UK.

One is to look for signatures ofconsciousness in brain activity, inthe hope that this takes us closer tounderstanding what it is. Variousbrain areas have been found to be


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IT HAS been called the Goldilocksparadox. If the strong nuclear force

which glues atomic nuclei togetherwere only a few per cent stronger thanit is, stars like the sun would exhausttheir hydrogen fuel in less than a second.Our sun would have exploded long agoand there would be no life on Earth. Ifthe weak nuclear force were a few percent weaker, the heavy elements thatmake up most of our world wouldntbe here, and neither would you.

If gravity were a little weaker thanit is, it would never have been able tocrush the core of the sun sufficientlyto ignite the nuclear reactions that

create sunlight; a little stronger and,again, the sun would have burned all ofits fuel billions of years ago. Once again,we could never have arisen.

Such instances of the fine-tuningof the laws of physics seem to abound.Many of the essential parameters ofnature the strengths of fundamentalforces and the masses of fundamentalparticles seem fixed at values that arejust right for life to emerge. A whiskereither way and we would not be here.It is as if the universe was made for us.

What are we to make of this? One

laws suitable for life because, againhow could it be any other way?

The multiverse idea is not withotheoretical backing. String theory,our best attempt yet at a theoryof everything, predicts at least10500universes, each with differentlaws of physics. To put that numbeinto perspective, there are an estim1025grains of sand in the Sahara de

Fine-tuned fallacy

Another possibility is that there isnothing to explain. Some argue thathe whole idea of fine-tuning is wro

One vocal critic is Victor Stenger ofthe University of Colorado in Bouldauthor of The Fallacy of Fine-tuningHis exhibit A concerns one of thepre-eminent examples of fine-tunthe unlikeliness of the existence ofanything other than hydrogen, heland lithium.

All the heavy elements in your bincluding carbon, nitrogen, oxygenand iron, were forged inside distanstars. In 1952, cosmologist Fred Hoyargued that the existence of theseelements depends on a huge cosmi

possibility is that the universe wasfine-tuned by a supreme being God.

Although many people like thisexplanation, scientists see noevidence that a supernatural entity isorchestrating the cosmos (see page 46).The known laws of physics can explainthe existence of the universe that weobserve. To paraphrase astronomerPierre-Simon Laplace when asked byNapoleon why his bookMcaniqueClestedid not mention the creator:we have no need of that hypothesis.

Another possibility is that it simplycouldnt be any other way. We findourselves in a universe ruled by laws

compatible with life because, well,how could we not?

This could seem to imply that ourexistence is an incredible slice ofluck of all the universes that couldhave existed, we got one capable ofsupporting intelligent life. But mostphysicists dont see it that way.

The most likely explanation forfine-tuning is possibly even moremind-expanding: that our universeis merely one of a vast ensemble ofuniverses, each with different laws ofphysics. We find ourselves in one with

Why is theuniverse

just right?

The mostlikely

explanationof fine-tuningis that ouruniverse is

merely oneof many


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coincidence. One of the key steps totheir formation is the triple alphaprocess in which three helium nucleifuse together to form a carbon-12nucleus. For this reaction to occur,

Hoyle proposed that the energy of thecarbon-12 nucleus must be preciselyequal to the combined energy ofthree helium nuclei at the typicaltemperature inside a red giant star.And so it is.

However, Stenger points out that in1989 a team at the Technion-IsraelInstitute of Technology in Haifa showedthat, actually, the carbon-12 energylevel could have been significantlydifferent and still resulted in the heavyelements required for life.

There are other problems with the

fine-tuning argument. One is the factthat examples of fine-tuning are foundby taking a single parameter a forceof nature, say, or a subatomic particlemass and varying it while keepingeverything else constant. This seemsvery unrealistic. The theory ofeverything, which alas we do not yetpossess, is likely to show intimateconnections between physicalparameters. The effect of varying onemay very well be compensated for byvariations in another.

Then there is the fact that we onlyhave one example of life to go on, sohow can we be so sure that differentlaws could not give rise to some otherliving system capable of ponderingits own existence?

One example of fine-tuning,however, remains difficult to dismiss:the accelerating expansion of theuniverse by dark energy. Quantumtheory predicts that the strength of thismysterious force should be about 10120times larger than the value we observe.

This discrepancy seems

extraordinarily fortuitous. Accordingto Nobel prizewinner Steven Weinberg,if dark energy were not so tiny,galaxies could never have formed andwe would not be here. The explanationWeinberg grudgingly accepts is thatwe must live in a universe with ajust right value for dark energy.The dark energy is still the onlyquantity that appears to require amultiverse explanation, admitsWeinberg. I dont see much evidenceof fine-tuning of any other physicalconstants. Marcus Chown

The existenceof elementsother thanhydrogen,helium andlithiumdepends on acoincidence

A GOLDILOCKS UNIVERSE

The values of many fundamental constants appear to lie

within narrow boundaries that allow life to exist. In 2000,

the UKs Astronomer Royal Martin Rees boiled them downto six in his bookJust Six Numbers

NUMBER

N, the ratio of the strengths of two

fundamental forces, electromagnetism

and gravity

VALUE

about 1036

IN WHAT WAY IS IT FINETUNED?

Ndetermines the minimum size of sunlike

stars. It tells us how big an object must

be before its gravity can overcome the

repulsive electromagnetic forces that keep

atomic nuclei apart, igniting nuclear fusion.

A larger value would not matter very much,

but ifNwere lower, stars would be smaller

and burn through their fuel more quickly,

making the evolution of life unlikely.

NUMBER

, the proportion of the mass of a

hydrogen atom that is released as energy

when it is fused into helium inside a star

VALUE

0.007IN WHAT WAY IS IT FINETUNED?

The fusion of hydrogen into helium is

the first step in forming heavier elements

and thus makes complex chemistry, and

life, possible. Ifwere slightly smaller,

nuclear fusion would be impossible and

the universe would consist only of

hydrogen. If it were slightly larger, all the

universes hydrogen would have been

consumed during the big bang and stars

would not exist.

NUMBER

, the ratio of the actual density of matterin the universe to the theoretical critical

density which would cause the universe

to collapse eventually under its own gravity

VALUE

about 0.3


is one of the factors that determines

how fast the universe expands. If it were

higher, the universe would have collapsed

long ago; if it were lower, expansion

would have been too rapid to allow stars

and galaxies to form.

NUMBER

, the cosmological constant, or the

energy that arises from quantum

fluctuations of the vacuum

VALUE

about 0.7


is the leading contender for the

mysterious force that is accelerating the

expansion of the universe. A smaller valu

would not be a problem, but if it were mu

larger the universe would have expanded

so rapidly that stars or galaxies would no

have had time to form.

NUMBER

Q, the amount of energy it would take

to break up a galactic supercluster as a

proportion of the total energy stored in

all of its matter

VALUE

about 10-5

IN WHAT WAY IS IT FINETUNED?Qis a proxy measure of the size of the

tiny fluctuations in the early universe

that were eventually amplified into stars

and galaxies. If it were smaller the univer

would be inert and structureless; larger

and the universe would be dominated by

black holes by now. Neither case would

support life.

NUMBER

D, the number of spatial dimensions

VALUE

3

IN WHAT WAY IS IT FINETUNED?With four spatial dimensions the orbits of

planets would be unstable, while life wou

be impossible with just two.


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28| NewScientist: The Collection| The Big Questions

How do I

know I exist?IN A nutshell, you dont.

Philosopher Ren Descartes hitthe nail on the head when he wrotecogito ergo sum. The only evidenceyou

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New Scientist the Collection Issue 1 - 2014 UK