The View From the Centre of the Universe - Nancy Ellen Abrams & Joel R. Primack

8/14/2019 The View From the Centre of the Universe - Nancy Ellen Abrams & Joel R. Primack

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THE VIEW FROM THE CENTRE OF THE UNIVERSE

Nancy Ellen Abrams & Joel R. Primack

After thousands of years of abstract theorizing, cosmology isinally coming close to a testable theory to explain the naturef the universe. Abrams and Primack argue we need the

modern equivalent of a creation myth to help fix the new

osmological ideas in our minds.

Those of us who are alive today have an extraordinarypportunity the opportunity to see everything afresh throughnew understanding of the universe itself. We are witnessingfull-blown scientific revolution in cosmology, the branchf astronomy and astrophysics that studies the origin andature of the universe. The unrestricted, dataless fantasizingf theorists has been replaced by reliable theory tested againsthe entire visible universe. What is emerging is humanitysirst picture of the universe as a whole that might actually berue. We are the first humans privileged to see a face of theniverse no earlier culture ever imagined. It is possible for theirst time not only to understand the universe intellectually buto start developing imagery that we can all use to grasp thisew reality more fully and to open our minds to what it may

mean for our lives and the lives of our descendants. As we do

his, we will discover our extraordinary place in the cosmos.We dare not undervalue this immense privilege, even though


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t is happening at the same time as some of the most barbaricnd self-defeating behaviour our species has ever exhibited.

This is all the more reason we need it.The last time Western culture shared a coherent

nderstanding of the universe was in the Middle Ages. For ahousand years, Christians, Jews, and Muslims believed thathe earth was the immovable centre of the universe and all theplanets and stars revolved on crystal spheres around it. Theierarchy continued on earth: God had created a place for very person, animal, and thing in a great chain of being. This

picture of reality made sense of the rigid social hierarchy of hat time. The medieval picture was destroyed by earlycientists like Galileo. The cosmic hierarchy lost itsredibility as the organizing principle of the universe and waseplaced with the Newtonian picture: a universe of endlessmptiness randomly scattered with stars, and our solar systemn no special place. This picture was not based on evidencebut was an extrapolation from Newtonian physics, whichccurately explains the motions of the solar system but by no

means the entire universe. The modern world has so deeplybsorbed this bleak picture that it seems like reality itself.

Until the late twentieth century, there was virtually no reliablenformation about the universe as a whole. That has changed.

Astronomers can now observe every bright galaxy in thevisible universe and because looking out into space isooking back in time can even see back to the cosmic Dark

Ages before galaxies formed and study in detail the heat

adiation of the Big Bang. The great movie of the evolution of he universe is coming into clearer focus: we now know that


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hroughout expanding space, as the universe evolved, vastlouds of invisible, mysterious non-atomic particles calleddark matter collapsed under the force of their own gravity.n the process they pulled ordinary matter together to formalaxies. In these galaxies generations of stars arose, whosexplosive deaths spread complex atoms from which planets

would form around new stars, providing a home for life suchs ours to evolve. Clusters, long filaments, and huge sheet-ike superclusters whose building blocks are galaxies haveormed along wrinkles in spacetime, which were apparently

enerated at the earliest moments of the Big Bang and etchednto our universe forever. Every culture has had a story of therigin of the universe, but this is the first one that notoryteller made up we are all witnesses on the edges of our eats.

The possession of this new picture is a gift so extraordinaryhat most of us dont know what to do with it. We have beeniving for centuries in a black and white film. There were nobvious gaps in the scenes before us, so we didnt notice thatnything was missing. Becoming aware of the universe is likeuddenly seeing in colour, and that changes not just whats far way but whats right here. The universe is here, and its

more coherent and potentially meaningful for our lives thannyone imagined.

Most of us have grown up thinking that there is no basis for eeling central or even important to the physical cosmos. But

with the new evidence it turns out that this perspective is

othing but a prejudice. There is no geographic centre to anxpanding universe, but we intelligent creatures are central or


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pecial in multiple ways that derive directly from physics andosmology, and this article discusses two of them: we are

made of the rarest material stardust and we are at theentre of all possible sizes in the universe. In our new book,

The View from the Centre of the Universe we also explainhat we are at the centre of the habitable zone of both the solar ystem and the Milky Way and at the centre of our visibleniverse, and we are living at the midpoint of time for theniverse, for Earth, and for the human species. Each form of entrality has been a scientific discovery, not an

nthropocentric way of reading the data. Pre-scientific peoplelways saw themselves at the centre of the world, however hey imagined their world. They were wrong on the details,but they were right on a deep level: the human instinct toxperience ourselves as central reflects something real abouthe universe, something independent of our viewpoint.

The Rarest MaterialExcept for hydrogen, which makes up about a tenth of your weight, the rest of your body is made of stardust. Hydrogennd helium, the two lightest kinds of atoms, came straight outf the Big Bang, while a little bit more helium and essentiallyll other atoms were created later by stars. The iron atoms inur blood carrying oxygen at this moment to our cells cameargely from exploding white dwarf stars, while the oxygentself came mainly from exploding supernovas that ended theives of massive stars. Most of the carbon in the carbonioxide we exhale on every breath came from planetary

ebulas, the death clouds of middle-size stars a little bigger han the sun. We are made of material created and ejected into


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he Galaxy by the violence of earlier stars. To understand howhis happened to appreciate the millions or billions of yearst takes a star to produce a comparatively tiny number of eavy atoms, and the tremendous space journeys of thosearticles of stardust that have now come together to incarnates is a first step toward finding our place in the cosmos.

All the stars, planets, gas, comets, dust, and galaxies that weee all forms of visible matter make up only about half aercent of whats out there. Most of the matter in the universes neither atomic nor visible. It is not even made of the

protons, neutrons, and electrons that compose atoms. Its antterly strange substance called cold dark matter, and itsxistence was only established late in the 20th century. But itccounts for about 25% of the universe. Dark matter neither mits, reflects nor absorbs light or any other kind of radiation,ut its immense gravity holds the spinning galaxies together.

But 70% of the density of the universe is not even matter ts dark energy. Dark energy causes space to repel space.

The more space there is and increasing amounts of space arenevitable in an expanding universe the more repulsion. The

more repulsion, the faster space expands, and this can lead ton exponentially increasing expansion possibly forever. The

Double Dark theory explains how dark matter and dark nergy interact over time to create the universe we observe.

Dark energy is in the nature of space itself. The Double Dark heorys history of the universe is basically this: in the earlyniverse there was relatively little dark energy because there

was relatively little space the universe hadnt had time toxpand very much, but there was the same amount of dark


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matter then as now. For about nine billion years, theravitational attraction of the dark matter slowed the rate of xpansion. The dark matter thinned out as the universexpanded, but since dark energy is a characteristic of space, itever thins out; instead its relative importance hasremendously increased with the amount of space. Now theepulsive effect of the dark energy has surpassed theravitational attraction of dark matter as the dominant effectn large scales in the universe, and expansion is no longer lowing down but accelerating. The turning point was about

our and a half billion years ago coincidentally just whenur solar system was forming.


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All earlier cosmologies have been shared through symbolicmages and stories. We too need to visualize our universe ot just random fragments of it, which is all that even the

most stunning NASA astronomical photos give us, but thewhole so that we can see where we fit. Since 99% of the

niverse is invisible, the only way to visualize the whole isymbolically.


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The Pyramid of All Visible Matter borrows an imageveryone in the United States possesses: the pyramid toppedy the all-seeing eye, which appears on the back of the dollar

bill. The pyramids capstone is separated and floating abovet, blazing with light, and dominated by an eye. This symbolan represent all the visible matter in theniverse all the matter that people until the late twentiethentury thought existed. The volume of each section of the

pyramid is proportional to the density of that particular ngredient in the universe. The large bottom part of the

yramid represents the lightest atoms: hydrogen and helium,which are so plentiful that they far outweigh all the heavytoms the stardust that makes up not only living things but

Earth and all rocky planets in the universe. Within theapstone, the fraction of stardust associated just with livinghings or the remains of living things is very tiny. Within that

very tiny fraction, the matter associated specifically withntelligent life is vanishingly small yet it is only that whichooks at and grasps this pyramid. The very human-lookingye at the centre of the capstone represents the trace bit of tardust associated with intelligent life. The eye is the onlyart not drawn to scale. Think of it as being like an enlargedetail of a city centre, inset on the corner of a large-scale map.

The inset is way out of proportion to the size of thingsurrounding it, but everyone knows that an inset on a map is aoom-in visualizing something important on a different sizecale. Here, in the same way, the eye on the capstone is a

oom-in to the presence of intelligent life. Without a zoom-inwe could not even see the matter associated with intelligence


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n the pyramid, since it is so rare. Intelligence bursts out onlyrom tiny bits of stardust

The Pyramid of all Visible Matter stands on the solid groundf Earth with a few plants for emphasis. But now we knowhat there is a hidden base extending deep underground. Thiss shown in the second figure, which we call the Cosmic

Density Pyramid.


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When astronomers look into space, they see only thelluminated half a percent of whats out there. It is as though


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reat fleets of ghost ships made of dark matter sail throughhe cosmic ocean of dark energy, but in the blackness all weumans see are a few beacons lit at the tips of the tallest

masts. Ordinary matter interacts with itself: particles interacto form atoms, atoms interact to form molecules, and under ateast some circumstances molecules can form living cells andventually evolve into higher life forms. But dark matter doesone of this. When viewed in computer simulations that makeark matter visible, the stuff behaves like nothing anyone hasver seen before. Gravity swings clumps of it around in the

resence of other clumps, but they can pass right through eachther. Dark matter has some of the properties people imaginef ghosts: it goes through things, yet it has power over therdinary world. Our kind of matter does not take up muchpace or contribute much to the total density of the universe,ut it contributes out of all proportion to the richness of theniverse.


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The centre of all possible sizes

n mathematics numbers go on infinitely in both directions,but in physics there are a largest and a smallest size. Thenterplay of relativity and quantum mechanics sets themallest size: general relativity tells us that there cant be

more than a certain amount of mass squeezed into a region of ny given size. If more mass is packed in than the region canold, gravity there becomes so intense that the region itself he space collapses to no size at all: a black hole. Any object

ompressed enough will hit this limit and suddenly become ablack hole. Meanwhile, quantum mechanics also sets aminimum size limit but in a very peculiar way. The size of

particle is actually the size of theegion in which you can confidently locate it. The smaller theegion in which the particle is confined, the more energy itakes, and more energy is equivalent to larger mass. Thereurns out to be a unique, very small size where the maximum

mass that relativity allows to be crammed in without theegion collapsing into a black hole is alsohe minimum mass that quantum mechanics allows to beonfined in so tiny a region. That size, about 10-33 cm, isalled the Planck length. We have no way to talk or evenhink about anything smaller in our current understanding of physics. The largest size we can see is that of the visibleniverse; the distance to the cosmic horizon is about 1028 cm.

From the Planck length to the cosmic horizon is a difference

f about 60 orders of magnitude. The number 1060 isxtremely big, but its not infinite. Its comprehensible. With


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t, we have something to compare our size to. Adapting andea of Sheldon Glashow, a 1979 Nobel laureate in physics,

we borrow the ancient symbol of the uroboros a serpentwallowing its tail and reinterpret it as the Cosmic

Uroboros.

The Cosmic Uroboros represents the universe as a continuity

f vastly different size scales. The tip of the serpents tailorresponds to the Planck length, and its head to the visible


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niverse. Travelling clockwise around the serpent from heado tail, the icons represent the size of the cosmic horizon1028 cm), the size of a supercluster of galaxies (1025), aingle galaxy, the distance from Earth to the Great Nebula in

Orion, the solar system, the sun, the earth, a mountain,umans, an ant, a single-celled creature such as the E. coliacterium, a strand of DNA, an atom, a nucleus, the scale of he weak interactions (carried by the W and Z particles), andpproaching the tail the extremely small size scales on which

physicists hope to find massive dark matter (DM) particles,

nd on even smaller scales a Grand Unified Theory (GUT) .

The size of a human being is near the centre of all possibleizes. And conscious beings like us couldnt be anywherelse. Much smaller creatures would not have enough atoms toe sufficiently complex, while much larger ones would suffer rom slow internal communication (limited by the speed of ight) which would mean that they would effectively beommunities rather than individuals, like groups of ommunicating people, or supercomputers made up of manymaller processors.

On different size scales, different physical laws controlvents. For example, gravity is all-powerful on the scale of

planets, stars, and galaxies, but on the sub-atomic scale,ravity is utterly irrelevant, and the weak and strong forcesontrol. On neither of these size scales is electromagnetismmportant, yet on the human scale its what makes chemistry

work and our bodies function. Size matters. The jurisdictionf physical laws is limited to a range of size scales, and this is


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he reason we cant extrapolate from what is true on earth towhats true in the universe nor can we extrapolate safely inny context when the numbers or sizes were dealing withiffer by many orders of magnitude. This was a fatal flaw of he Newtonian picture.

The island of size scales surrounding human beings is thereality in which common sense works and normal physicalntuition is reliable. Most of us are rarely conscious of nything smaller than an insect or larger than the sun. Theseizes define humanitys native region of the universe, our true

omeland. Its not a geographical location: its a point of view a setting of the intellectual zoom lens. We have named thisentral range of size scales Midgard because in the Old

Norse mythological cosmos, Midgard was the human world.t was an island representing stability and civilized society inhe middle of the world-sea, the Norse universe. The world-ea was large, and there was room not only for Midgard butor the land of the giants and the land of the gods. This is anxcellent description metaphorically, of course of

Midgard as the centre of the expanding universe. Our Midgard is the island of size scales that are familiar andomprehensible to human beings. But beyond the shores of

Midgard in one direction outward into the expandingworld-sea is the land of incomprehensibly giant beings, likeblack holes a million times the mass of the sun and galaxiesmade of hundreds of billions of stars. In the other directionrom Midgard inward, toward the small lies a living

ellular world, and beyond that the quantum world, and thesemicrolands are the evolutionary and physical sources of


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verything we are. That may not make them gods, butompared to us they are more prolific, more ancient,niversal, and omnipresent. Like the Norse Midgard, our

Midgard is not isolated from these other lands in the world-ea.


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The bridge is the Cosmic Uroboros.Midgard spans about fourteen orders of magnitude, from 10-2m to 1012 cm, holding everything for which people haventuition. The figure also shows the approximate decade andechnology by which scientists discovered the rest of the

Cosmic Uroboros. The concept of Midgard has implications.People disagree on just about everything that has to do withpirituality, but the one thing they do tend to agree on is that


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Transcendence should not be thought of as an imaginaryeap to some place outside the universe. Transcendence is

what happens many times within this universe, every fewpowers of ten. For example, on the atomic and subatomiccales, human means nothing. There is no humanness to our toms. Whether atoms are inside us, inside a rock, or driftinghrough space, is all the same to them. On the atomic scale,herefore, even inside our own bodies we do not exist. Were something that transcends atoms. In the same way theniverse as a whole transcends familiar Midgard. Amazingly,

n this interpretation the difference between spiritual andphysical becomes in an approximate way quantifiablewith powers of ten. Things larger than about 1012 cm, or maller than about 10-2 cm, can only be known throughcience and only experienced, if at all, spiritually. Thisncludes most of the universe. The Cosmic Uroboros is aontext for those exotic size scales of the universe that no onever had a connection with before. Seeing and living on

multiple levels at once is what cosmic connection is allbout. It is not mystical; it is as practical and essential ashe visualizations that athletes do before a competition, or oncert pianists before they go out on stage. It situates us ineality at our best.

As a culture we now have the scientific ability to see so muchmore deeply into the universe than ancient people, yet mosteople experience the universe so much less and connect witht almost not at all. Widespread cultural indifference to the

niverse is a staggering reality of our time and possibly our iggest mental handicap in solving global problems. We have


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ibraries full of creation stories, and a culture of scepticism.Without a believable story that explains the world we actuallyive in, people have no idea how to think about the bigicture. And without a big picture, we are very small people.

A human without a cosmology is like a pebble lying near theop of a great mountain, in contact with its little indentation inhe dirt and the pebbles immediately surrounding it, butblivious to its stupendous view.

Religious stories can still arouse in many people a sense of ontact with something greater than we are but that

something is nothing like what is really out there. We dontave to pretend to live in some traditional picture of theniverse just to reap the benefit of the mythic language

popularly associated with that traditional picture. Peopleround the world should be able to portray our universe withll the power and majesty that earlier peoples evoked inxpressing their own cosmologies. Mythic language is not the

possession of any specific religion but is a human tool, andwe need it today to talk about the meaning of our universe.Big changes are happening on our planet, and shepherdingurselves through them successfully is going to requireremendous creativity. An essential ingredient may be aosmic perspective, and such a perspective is just becomingvailable.

Nancy Ellen Abrams and Joel R Primack's The View from the Centre of theU i i bli h d b F th E t t

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The View From the Centre of the Universe - Nancy Ellen Abrams & Joel R. Primack