A Recovering Physicist: In the Center
This is a service I presented at the First Parish Church of Groton, Unitarian Universalist, on August 20, 2006. — Keith Dawson
I light the chalice this morning for the mysteries of quantum, cosmos, mind, and spirit — for a Universe that is, in the suspicion of the biologist J. B. S. Haldane, “not only queerer than we suppose, but queerer than we can suppose.”
I have a few quotes to bring us into the spirit of the thing.
Niels Bohr, one of the fathers of quantum mechanics and explicator of the Copenhagen Interpretation of quantum reality: Those who are not shocked when they first come across quantum theory cannot possibly have understood it.
Richard Feynman, 20th-century physicist, winner of the Nobel Prize, and co-developer of quantum electrodynamics: I think it is safe to say that no one understands quantum mechanics. Do not keep saying to yourself, if you can possibly avoid it, “But how can it be like that?”… Nobody knows how it can be like that.
Freeman Dyson, 20th-century deep thinker in physics: In a certain sense… you won’t really understand quantum mechanics deeply unless you also understand the nature of mind.
John Lilly, mid-to-late 20th-century researcher on dolphins and fearless explorer of states of consciousness: In the province of the mind, what one believes to be true either is true or becomes true.
Meister Eckhart, 14th-century German theologian, philosopher and mystic: When the soul wishes to experience something she throws an image of the experience out before her and enters into her own image.
Samuel Taylor Coleridge, 19th-century poet: What if you slept? And what if in your sleep, you dreamed? And what if in your dream you went to heaven and there plucked a strange and beautiful flower? And what if, when you woke, you had the flower in your hand? Ah! What then?
The practice of science, and the study of physics in particular, intends to ask and answer the question: what is really going on here, where we live?
Over my life my own view has moved from 18th- / 19th-century radical materialism, through questions about the relationship of consciousness to quantum causation, and out the other side of science altogether.
The ontology of materialism rested upon the illusion that the kind of existence, the direct “actuality” of the world around us, can be extrapolated into the atomic range. This extrapolation is impossible, however. — Werner Heisenberg (one of the founders of the quantum theory)
I now assume that consciousness is primary and that matter arises from it — not the other way around. I believe that the world we co-create is holy. One way of saying this is captured by Coleman Barks, modern-day translator of the 13th-century mystical poet Rumi:
The Sufis say the great world is the inner world, and the outer world of stores and restaurants and nations and three hundred billion galaxies is the small world. The inner world is your awareness. The outer is a kind of language for your inner. [With] that reversal, you can’t shoot a weapon into a place where four hundred people are if you think the great world is the inner world and each of those people is housing a treasure of consciousness. — Coleman Barks
This view I have arrived at is one few working scientists would admit to sharing. On the Web, for example, it’s common to see scorn directed toward any scientist who is even loosely involved with research at the boundary between science and religion, such as that funded by the Templeton Foundation. It is refreshing — and rare — to see a scientist even talking about wonder, beauty, and meaning in man’s place in the cosmos. Holiness is right off the table.
Useful as it is under everyday circumstances to say that the world exists “out there” independent of us, that view can no longer be upheld. — John Archibald Wheeler (protean 20th-century physicist)
Today I’m going to be opening up for you a summary of modern scientific cosmology based on the book The View from the Center of the Universe by Joel R. Primack & Nancy Ellen Abrams. The subtitle is “Discovering our Extraordinary Place in the Cosmos.” In this book Primack & Abrahms develop a picture that they call the meaningful universe. Their overall interpretation of scientific cosmology and its implications for our outlook on life places mankind squarely in the center of the cosmos, in a number of senses, with a position and a role full of significance. “The meaningful universe” is the antithesis of strict Newtonian materialism, while still abiding somewhere in the vicinity of scientific respectability.
Here is how Primack & Abrams describe the worldview from which we are now emerging. Newtonian materialism is:
...an imagined universe, where space is simply emptiness, stars are scattered randomly, and common sense is a reliable guide. In this imagined universe, we humans have no special place and often feel insignificant. — Primack & Abrams
The chief problem with the Newtonian view is that it accurately explains only the motions of planets around a star, not the universe as a whole. Things on different size scales behave very differently than the Newtonian picture would predict.
Physical laws that apply at one scale do not cease to be true at other scales; they just cease to matter. — Primack & Abrams
Until the late 20th-century we had no clear picture of the universe as a whole. I’m going to try to convey such a picture to you today. When you leave here I want you to be able to imagine the vision the 14th-century hermitess Julian of Norwich described. In her vision, Christ took her on a tour of creation, and:
He showed me a little thing, the quantity of an hazlenut, in the palm of my hand; and it was as round as a ball. I looked thereupon with eye of my understanding and thought: What may this be? And it was answered generally thus: It is all that is made. — Julian of Norwich
Here are some of the ways in which we, humans on planet Earth, are absolutely central to All That Is.
- We are at the center of size.
- We are made of the rarest stuff there is.
- We are at the center of the physical universe.
:: We are at the center of size ::
The size of a thing matters. Its size determines what kind of a thing it can be and how it can behave. Remember Primack & Abrams’ rule about physical laws ceasing to matter at different scales. Quoting them:
The size of a human being is at the center of all possible sizes in the universe. This amazing assertion challenges not only the centuries-old philosophical assumption that humans are insignificantly small compared to the vastness of the universe but also the logical assumption that there is no such thing as a central size. Both assumptions are false. — Primack & Abrams
The smallest size is called the Planck length. It is about 10-33 cm and is the size where quantum mechanics and general relativity are both important. (These two theories, both demonstrably accurate within certain domains, are fundamentally incompatible; hence the decades-long quest for a “theory of everything” that you have probably heard about.) At or below the Planck length we currently have no chance of figuring out what things are like.
On the scale of the Planck length, spacetime itself becomes a foam (according to Wheeler) or a bubbling sea of virtual black holes (according to Hawking) or a bucket of dust (according to Wheeler again) or a weave of knots or tangles (according to Ashtekar, Rovelli, and Smolin). In short, it’s weird, but beyond that nobody really knows. — John Baez (professor of mathematical physics, UC Riverside)
The largest size in the universe is the farthest we can see, the distance to our “cosmic horizon.” It is about 14 billion light-years or 1028 cm. The difference in scale between the Planck length and the cosmic horizon is about 1060.
Primack & Abrams use an ancient symbol to represent the size scales of the universe and our place in it: the Uroboros, the figure of a serpent swallowing its own tail. They prefer venerable, multilayered symbols because, as they say, “Cosmologies that have been meaningful for people’s lives have been communicated with symbolic images and stories.” Primack & Abrams call their adaptation the “Cosmic Uroboros.” Let’s get oriented to it. (Click on the thumbnail to open a larger version of the Cosmic Uroboros in a new window.)
- Look at the bottom of the circle. Everything about our everyday world takes place between the size of an ant (say) and the size of a mountain. This is about 5:00 to 6:30 on the circle — pretty close to the center. This is the “reality” within which common sense works and normal human intuition is reliable.
- On the scale where humans operate, the most important forces are electromagnetism and gravity. The electromagnetic force controls such things as chemical bonding, friction, and air resistance. The size a mountain can be is dictated by the balance of electromagnetic forces — which are the same strength everywhere — and gravity, which gets stronger the bigger the object involved.
- To a mouse or anything smaller, gravity hardly matters. Drop a mouse down a 1000-foot mine shaft and, as long as the bottom is reasonably soft, the mouse will walk away unharmed. To a bacterium living in water, gravity is totally irrelevant.
- At the size of atomic nuclei, electromagnetism is overwhelmed by other factors — the strong and weak forces. Quantum effects come into play at this scale.
- Moving counterclockwise around the Cosmic Uroboros, we come to the realm of planets, stars, galaxies, galaxy clusters, and superclusters. In all this range, gravity rules. The superclusters are the largest structures there are. Remember how Newton believed that stars were scattered randomly throughout all space? He was wrong about stars but right at the level of superclusters.
- At still larger size scales, gravity again ceases to be dominant, overcome by the “dark energy” that fuels the expansion of the universe. (We’ll talk more about this later.)
- The reason the serpent is swallowing his tail is that the very smallest and the very largest may be made one, some day, by a “theory of everything,” or Grand Unified Theory as some call it. Remember we said that the tiny Planck length is a realm where both relativity and quantum effects matter? In one contender for a theory of everything, the research program (not yet a theory) called, somewhat misleadingly, “string theory,” the Planck scale is literally remapped to the largest scale.
:: We are made of the rarest stuff there is ::
Let’s get a handle on what the universe is made of, starting with ourselves.
- 10% of our body weight is hydrogen — and all of that hydrogen was made in the first second of the Big Bang. Almost all the rest of everything we see around us — our bodies, plants, rocks, the earth, other planets, the sun, other stars — is made of stardust.
We are stardust, we are golden. And we’ve got to get ourselves back to the garden. — Joni Mitchell
- 20% of us is carbon and nitrogen. This came from planetary nebulas blown off by stars a bit more massive than our sun.
- Oxygen, neon, and most of the other heavy elements came from massive stars which at the end of their lives exploded as supernovas.
- Iron and everything heavier than that came from white dwarf supernovas.
There are about 50 supernovas a second in the visible universe.
The stuff we are made of was born in thermonuclear furnaces and traveled probably millions of light years to get here so our solar system could be born.
The optimist says we are made of stardust. The pessimist says we are made of the nuclear waste of burned-out stars.” — Primack & Abrams
We live in an unusually dense part of the universe. The area of our galaxy where the Sun revolves is about a million times more dense than the average for the visible universe. Our solar system is a trillion times more dense than that. And on Earth, the densest planet in the solar system, the density is a trillion times higher still.
The solar system consists of the sun and change. Jupiter is 1/1000 the mass of the sun, and all the other planets together add up to 40% of Jupiter.
I’m going to talk about these two diagrams, from Primack & Abrahms, that show man’s place in the universe of matter and energy. Again they deliberately use an ancient symbol, the pyramid with an eye at the top. The founding fathers of this country chose this symbol for our currency, in part because some of them were Masons and knew this symbol well. (Click on either thumbnail to open a larger version of the Visible Matter Pyramid, or the All Matter and Energy Pyramid, in a new window.)
- All the matter that we can see in the universe — because it emits or reflects light or other electromagnetic radiation — adds up to about 1/2 of 1% of the stuff there is.
- Another 4% of the total is ordinary atoms out between the galaxies, invisible to us.
- Massing five times more than all this ordinary matter is the so-called “cold dark matter” that makes galaxies and clusters of galaxies run on cruise control. The existence of CDM is the best postulate scientists have come up with to explain why galaxies rotate as if all the luminous matter we can see were embedded in a large, invisible sphere of molasses. Cold dark matter does not interact with light or with ordinary matter, except by its gravitation. It is invisible even in theory.
- And rounding out the picture, fully 70% of the mass of the universe is not matter at all but “dark energy” (as Einstein taught us, matter and energy are equivalent) causing space to expand ever faster.
The tip of the pyramid is where all the complex, interesting stuff happens. Dark energy does nothing but make space repel space. Cold dark matter interacts only gravitationally, and so it hasn’t built up the complex structures that ordinary matter has. We may be at the far tip of the matter pyramid, but we represent a vastly disproportional amount of the complexity and interest that has so far evolved in the universe.
:: We are in the center of the physical universe ::
When the earth was flat and the sky wheeled above it — as the ancient Egyptians believed — we were in the center. When the earth was round and the sun and planets and stars revolved around us on crystal spheres — the common belief in the Middle Ages — we were at the center. We were temporarily deposed from the center by Copernicus, Galileo, and Newton. Einstein, Edwin Hubble, and (Arno) Penzias and (Robert) Wilson have put us back in the center.
You’ve heard about the Big Bang. You’ve heard it said that the universe is expanding.
We are in the center of the expansion. (But then, so is everybody else.)
What we see as we look out into space is identical to what any observer in this universe would see: nearby stars, galaxies, clusters of galaxies, superclusters. Looking farther into space is looking back into time, because it takes time for light to get here (as Einstein taught us). The farther out we look, the faster things are moving away from us — we are at the center of the expansion. (But then, so is everybody else.)
The usual analogy people use to explain the way space expands is to imagine dots printed on the surface of an expanding balloon. An analogy I like better is that of raisins in a loaf of bread dough set aside to rise. As the dough expands, the raisins move away from one another in three dimensions at a speed proportional to their separation — because it is the fabric in which they are embedded that is expanding.
At the farthest distances we can see, the earliest galaxies formed 14 billion years ago. Beyond that there is blackness and then — the radiation of the Big Bang itself.
Here are two questions that should help to bring us into the mystery of the Big Bang.
Q Where did the Big Bang happen? There are two
A Here. Everywhere.
Q How big is the universe? (How big is the
part we can see?)
A The most distant galaxy we can see, whose light left it 14 billion years ago, is “now” 46 billion light years from us.
Let’s look at another symbol introduced by Primack & Abrams, which they call the Cosmic Spheres of Time. It deliberately echoes the picture of the crystalline celestial spheres that in the Middle Ages, across a number of cultures, represented the concensus cosmology. (Click on the thumbnail to open a larger version of the Cosmic Spheres of Time in a new window.)
- Inner sphere: the sun formed 4.5 billion years ago.
- Next out: Big Galaxies Form, perhaps 10 billion years ago.
- Third sphere: Bright Galaxies Form, 13 billion years ago.
- Outer sphere: Cosmic Background Radiation, 14 billion years ago.
The Cosmic Spheres of Time represent the visible universe, or everything that we can see. This visible universe, everything that we can know about directly, is a small part of a “bubble” of space. The bubble within which our visible universe exists — that is, the totality of space — is at least 100 times larger than the 14 billion light years that we can see, Primack & Abrams tell us, and most theories assume it is many orders of magnitude larger. Millions, billions, trillions of times larger.
Now consider this entire bubble, let’s say a trillion times bigger than everything that we can know. Hold it in the palm of your hand. This bubble is made of space. It is not a bubble “in” space, it is made of space. Space is not the empty, boring void that the Newtonian picture describes: it is the most dynamic thing there is. Here’s how a leading theorist of relativity describes space:
Space tells matter and energy how to move, and matter and energy tell space how to curve. — John Archibald Wheeler
At the largest size scales, larger than the cluster of clusters of galaxies in which we live, space is repelling itself and expanding ever faster. At the smallest size scales, down below the proton, space is full of a constant ferment of particles popping out of the vacuum, in between moments of time, and recombining to self-annihilate in a flash of energy.
Before the Big Bang, the universe went through a brief period of exponential expansion. In every moment it blew up to twice the size it was before. This blink of expansion is called “cosmic inflation,” and it lasted for 10-32 sec. In this instant the universe inflated by 1020, 1030, or more times in size.
The infinitesimal chunk of nothing that inflated to become all that we see today — Primack & Abrams call it a “sparkpoint” — was perhaps 100 Planck lengths in size, 10-31 cm — a billion billion times smaller than a proton. And it inflated to the size of a soccer ball. This is as much expansion as has occurred in the 14 billion years since. The inflationary expansion occurred in less time than light would take to cross a proton; therefore of course it occurred much faster than light.
186,000 miles per second isn’t just a good idea. It’s the law. — (author unknown)
The speed of light is only the speed limit for objects moving in space. The expansion of space itself is not bound by it. In the region beyond the farthest point we can see, galaxies are being carried away from us faster than light.
The entire universe has zero energy. The energy of its expansion is balanced by the (negative) gravitational potential energy of its contents. The universe has been called by Alan Guth, inventor of the theory of cosmic inflation, “the ultimate free lunch.”
Why did the Big Bang happen? Here’s the not even ironic view of Edward P. Tryon:
In answer to the question of why it happened, I offer the modest proposal that our Universe is simply one of those things which happen from time to time. — Edward P. Tryon: (professor of physics, Hunter College)
Whatever it was that happened, we are at the center of it. (But then, so is everybody else.)
Notes and Links
- [2006-08-23] NASA has just announced research offering direct evidence for the existence of cold dark matter.
- Visit Primack & Abrams’ site devoted to their book, The View from the Center of the Universe. If you couldn’t tell, I am a fan of this book. I recommend it to anyone with the slightest curiosity about cosmology. The book contains not a single equation.
- Regarding the scientific concensus about the topics and theories discussed in View from the Center: I came across this guide, hand-drawn by two physicists attending a 1996 scientific meeting. It sketches out “the history of how strongly cosmologists have believed their theoretical ideas” from 1965 to 1996. (Note that this chart predates the discovery in 1998 that the expansion of the universe is accelerating.) (If the above link should eventually cease to work, here is a local copy.)
- The background for this page is a detail from the Hubble Ultra Deep Field image, and you can see it all here (116 KB). In this image only two of the visible objects are stars; all the rest are distant galaxies, most in an early stage of their evolution. You can explore or download the entire HUDF image at the Hubble Site.
Most recently updated 2018-08-11