The universe has been putting on a striptease act for a long time. One by one it has shed the veils that cover up the truth about nature. At first the strip was boringly slow. The audience had to wait centuries before the first veil, which was the idea of a solid atom, came off. The atom is an ancient idea, dating back to Democritus and his followers. Those philosophers in ancient Greece couldn’t see an atom—neither can we, more than two thousand years later—but they reasoned that if you slice up an object, any object, eventually you’d arrive at a tiny piece that couldn’t be cut any smaller. The word atom comes from two Greek words that mean “not” and “cut.”
The striptease would have gone much faster if someone could have found a way to prove that atoms exist, but they couldn’t. Therefore, if you asked what the universe is made of, the answers you got back were all theory and no action. But it was certain that some kind of smallest unit must exist. Peeling away the veils moved incredibly fast starting in the eighteenth century, when experimenters actually began to experiment, and the behavior of chemical reactions gave the first clues that single, whole atoms were reacting with one another. Skip ahead to the twentieth century, when evidence was found for electrons, radiation, the nucleus, subatomic particles, and so on. One by one the building blocks of the atom were discovered. The universe could hide behind modesty no more.
So the audience was shocked when the last veil was dropped and behold, the dancer wasn’t there! If you keep slicing a loaf of bread into smaller and smaller units, the atom vanishes into the quantum vacuum. Something turns into nothing, as we’ve already seen. But there’s a subversive side to this striptease. Once the dancer vanishes, we are left with thinking about the universe rather than actually seeing it. Somehow we’re back at square one with the ancient Greeks, relying on logic and speculation instead of provable facts.
Right now, outside public view, there is a “battle for the heart and soul of physics” going on, to borrow a phrase from the prominent journal Nature. Two highly respected physicists, George Ellis and Joe Silk, wrote an article in 2014 that raises alarms over just this problem of pure thinking replacing data and facts. Can pure thinking be called science, which for five hundred years has pursued the truth through measurements and experiments? Once you get down to nothingness, the zero point of the universe, the possibility of doing experiments comes to an end. How bothered should we be?
Here’s an analogy from everyday life. See yourself about to cross the street at a busy city intersection. In front of you is the Walk/Don’t Walk sign. Cars are pulling up to the intersection constantly, and some are turning right on red. Your object is to cross the street without getting hit by a car. To make this a real challenge, you must wear blinders, the kind that horses wear when they pull carriages in Central Park, so you can only look straight ahead.
What is your strategy for not getting hit? Your line of vision is very narrow, and all you really have to work with are clues. This is much the same as a physicist trying to look into a black hole or before the big bang or inside the quantum vacuum. For you, the clues turn out to be quite useful. You can use your hearing to listen for cars. You can see when the Walk sign is on. There are other pedestrians on the corner; you can observe them and step off the curb when they do. This gives you a pretty good idea of when it’s safe to cross the street. But you don’t actually know. The probability is high that you won’t get hit by a car, and that’s the most you can say.
If you want to see the reality that lies inside a black hole, you can’t. You can only figure out the probabilities based on various clues. The same holds true for almost every mystery we are covering in this book. Science has gotten to the point where things are either too small, too big, too far away, or too inaccessible to the most powerful instruments in the world. If you take the tiniest subatomic particle that the largest accelerators, costing billions of dollars, can blast out of the quantum field, the very smallest particles—or whatever they turn out to be—are still 10 million billion times smaller than any accelerator can detect.
Which brings us to a fork in the road. One sign says, This way to more thinking, another sign says Dead end. Science hates dead ends, so physics keeps diving into deeper and deeper thinking. One camp keeps faith with the time-tested practice of doing experiments and campaigns to build ever bigger particle accelerators—even though, by some calculations, the energy needed for such a gigantic machine would equal all the electricity in all the power grids on Earth. Another camp abandons experiments and opts for pure thinking—the old Greek way—in the hopes that nature will one day offer new evidence that we can’t see right now.
Sherlock Holmes and Albert Einstein have one thing in common: they believed in logic. Einstein had total faith in the logic behind relativity. He once said, only half in jest, that if his theory had proved incorrect, “[t]hen I would have felt sorry for the dear Lord.” It’s strange to think that if you hold a loaf of bread in your hand and ask, “What is this made of?” the ultimate answer is “Nothing, but we have lots of good ideas about that.” Such is the present situation when pursuing the mystery of what the universe is made of. There has to be a better way.
GRASPING THE MYSTERY
When a problem arises where the evidence is kept out of sight, it’s known in science as a black box problem. For example, imagine that new cars roll off the assembly line with their hoods sealed shut. No one can see the car’s engine—it’s in a black box—but you can still tell a lot about how the car runs. One by one, facts can be amassed. When the car suddenly stops, for example, you will eventually discover that it needs gas. Because the dashboard lights up, you deduce that the engine involves electricity in some way.
Black boxes are fun and frustrating at the same time, and scientists tend to love them. But until you can open the hood, you will never know how a car engine actually works. It’s very disturbing, then, to realize that the universe itself is the ultimate black box. If a physicist sets out to understand what the universe is made of, everything seems to be on the table. The laws of nature are well understood, as are the properties of matter and energy. The standard model of quantum field theory can account for every fundamental force except gravity. Even though gravity is a stubborn holdout, tiny increments of progress continue to be made (at the moment the two leading rivals are known as loop quantum gravity and superstring quantum gravity, both highly esoteric), and everyone keeps murmuring that slow and steady wins the race.
Unless it’s all reached a dead end. The infant universe was cooked up where no one can go, or even name the raw materials that were used. As Ruth Kastner, an accomplished philosopher of science, has commented, the material universe is like the Cheshire Cat in Alice’s Adventures in Wonderland. Its body has faded away, leaving only a faint grin hanging in the air. Physics studies the grin in an attempt to describe the cat. Is this a futile enterprise?The Cheshire Cat metaphor originated with the work of far-seeing physicist John Archibald Wheeler to describe the collapse of matter into a black hole. Einstein had a witty way of putting it: “Before my theory, people thought that if you removed all the matter from the universe, you would be left with empty space. My theory says that if you remove all the matter, space disappears, too!” When you consider that a black hole devours literally the entire structure of physical reality, it’s easy to look upon even a huge cluster of whirling galaxies as nothing more than the cat’s grin.
Physics wants to find a single explanation of reality. But there’s no getting past the fork in the road. One way leads to a universe where matter is substantial, reliable, and well understood. Quantum physics more or less abolished this as a viable route to reality, even though large numbers of working scientists still choose this path. They have their reasons, which we’ll examine. The other way leads to a total rethinking of the universe, based on the fact that material existence is an illusion. The dilemma is like Robert Frost’s famous poem that begins, “Two roads diverged in a yellow wood, / And sorry I could not travel both…”
Most of the unsettled arguments in quantum theory turn on which road you decide to take. Pure thinking or new data? As in Frost’s poem, the most frustrating aspect is that you’ll never know what happens on the road not taken.
PRYING OPEN THE BLACK BOX
Cosmologists accept that the visible universe constitutes only a fraction of the matter and energy unleashed by the big bang. The vast bulk of creation almost instantly disappeared, but this didn’t remove dark matter and energy from the equation. For example, empty space isn’t empty but contains huge amounts of untapped energy at the quantum level. The exact amount of energy has been calculated, but it turns out, on the evidence of how fast the universe is expanding, the numbers are way, way off. As subatomic particles “foam” up from the vacuum, the forces involved require enormous amounts of energy. The density of energy in a cubic centimeter of empty space is expressed as a number called the cosmological constant.
Unfortunately, this number turns out to be off by 120 orders of magnitude (10 followed by 120 zeros). Empty space is far emptier than quantum theory would have it. Somehow, it is supposed, all the forces that should be roiling inside the vacuum state cancel each other out. More than one physicist has called this perfect cancellation “magical.” At best, what’s happening is due to dark energy and its effects on the galaxies, but dark energy is high on the list of things that so far at least can’t be experimented on.
If it turns out that the hidden side of creation is actually in control of the expanding universe, we confront possibilities that defy the accepted view of the laws of nature (the standard model). In a nutshell, when solid, reliable matter vanished, so did the concept of “matter.” This will turn out to be tremendously important if all the things we take for granted about physical objects—the heaviness of rock, the sweetness of sugar, the brightness of a diamond—are created in the human mind. This would imply that the whole universe is created in the human mind—but we’re not there yet.
To give an idea of the gap, no one really knows why the physical universe exists in the first place. During the big bang, energy was wildly active, producing a “shakeup” of space-time. The calculations of physics can’t tell us why such violent agitation didn’t doom matter to be torn apart. If primordial matter was shaken as much as the equations say it was, either the infant cosmos would have collapsed in on itself by the tremendous force of condensed gravity (as in a black hole) or the surviving universe would have been pure energy. Yet it’s obvious that matter did come into existence; therefore, the equations must be tinkered with until they fit how things are. This tinkering can look a lot like fudging the numbers.
Reality is obviously more than physical, and trying to squeeze quantum “stuff” into a physical box isn’t what reality is telling us to do. Yet a belief in physicality remains part of most scientists’ DNA. They point to the success of the standard model and promise that all the remaining gaps will soon get filled in. “We’re almost there” fuels optimism. Nonphysical explanations for the universe would go back to the starting point, based on accepting that “matter” is a worn-out concept. Given a choice between “We’re almost there” and “We haven’t even started,” most scientists pick the former without question.
WHAT WE SEE
Before radically challenging the physicalist position, credit must be given to the knowledge it accumulated. It’s an impressive achievement, all of it based on the maxim “Seeing is believing.” There’s certainly a lot to see. Within 14 billion light-years or so (the actual universe may be much larger), there are probably 80 billion galaxies, which astronomers classify as large and small, spiral, elliptical, or irregular in shape, “normal” (showing no major activity in their centers), or “active” (exploding with vast amounts of energy and matter coming out of their centers).
Within a typical galaxy like our own Milky Way, a large spiral type, there are as many as 200 to 400 billion stars. Most of these are called red dwarves; are small, faint, and red in color; and last for tens of billions of years. The stars we see in the night sky are much brighter, and they have whitish or bluish colors. These bright stars can be seen from much farther away, but what we see doesn’t reflect their true distribution. A high percentage of stars other than red dwarves are like our own sun, and many are now shown to be surrounded by planets. As we saw, if a percentage of these planets harbor the right conditions for life, then the camp that believes in randomness has an advantage over the anthropic camp, with its belief that life on Earth is special.*
In total, the universe contains as many stars as 1 followed by 23 zeros, or 100 sextillion. A staggering number, but by no means the most staggering. A vast amount of luminous matter, in the form of stars, lights up the galaxies. Even though there are more stars than grains of sand on Earth, they only make up 10 percent of the total mass in the observable universe. Calculating the total number of protons and electrons making up regular atomic matter, one comes up with 1 followed by 80 zeros, or 100 thousand trillion sextillion sextillion sextillion atoms! This is equivalent to 25 million sextillion Earths.
Here the visible trail dwindles away, because all this luminous matter accounts for approximately 4 percent of the “stuff” in the universe. Most of it, 96 percent or so, is “dark” and therefore unseen and unknown. But at least we have a credible inventory of the cosmos, as produced by NASA’s Wilkinson Microwave Probe (WMAP): 4.6 percent regular matter, 24 percent dark matter, and 71.4 percent dark energy. Most of the universe is at the very least quite exotic. Quite a black box indeed.
As things stand, dark matter and energy are surmises formulated by painstaking, elaborate lines of reasoning—their actual existence is several steps removed from “seeing is believing.” Some skeptics warn that physics is flirting with fantasy. Imagine that you are looking around the animal kingdom and see horses galloping through the open plains. Turning your gaze, you also see a one-horned sea mammal called the narwhal. Do these visible facts allow you to reason that unicorns are real, with the body of a horse and the horn of the narwhal? Our modern answer is no, but in the Middle Ages there wasn’t such a strict divide between the real and the mythical. Cosmology is currently saddled with a full menagerie of mythical creatures, from quarks and superstrings to the multiverse, created through mathematical inference alone.
Dark matter is a prime example of real-by-inference. First, dark matter is inferred from the speeded-up rotation of the stars in a typical galaxy. The stars are being pulled around by the gravitational force of some outside mass faster than physics can account for. (NASA uses gravity in the same way when it steers a space probe close to a huge planet like Jupiter or Saturn so that the planet’s gravity can serve as a slingshot, speeding up the probe as it whips past.) As normally measured, the typical galaxy doesn’t contain enough mass to explain the observed rotation, nor does the known universe.
Second, most galaxies are found in clusters of various sizes. Some are small, containing only a few galaxies, while others are massive, containing tens of thousands of galaxies and emitting vast amounts of X-rays. These giant clusters also seem to contain more mass than is counted up, either in stars or the gaseous material inside the cluster, which is only observed through X-rays. By inference, more matter must be contained somewhere inside the cluster. Finally, when distant background galaxies are observed as their light passes through a nearer cluster of galaxies (such as the Bullet Cluster), the bending of its light due to the gravitational field inside the near cluster—acting as a gravitational lens—indicates that a lot more dark matter resides inside the cluster. These three pieces of evidence are in agreement, based on the same variable, gravity. They result in precise numerical predictions that have been confirmed. The inferences being drawn aren’t weak, but they aren’t sufficient either.
To illustrate, imagine that you are in a windowless room that’s rotating like a star. You can feel the centrifugal force as you are bounced against the walls, and you infer that something is pulling on the room from the outside. That’s a strong inference, but you can see its limitations—to describe where the external force is coming from (a tornado, an angry elephant, a giant playing with his toys?), nothing can be said realistically with only an inference to go on, despite the finest calculations from inside the room telling you how strong the force is.
WHEN DARKNESS RULES
Since darkness appears to be the rule in creation, solving the mystery of what the universe is made of must begin there—and almost immediately gets stymied. Most cosmologists currently believe that dark matter is “cold,” meaning that within a year after the big bang, its particles were moving slowly in relation to the speed of light. (As you’ve come to expect, these particles are just a matter of conjecture at this point.) It’s also been proposed that dark matter may come in three types: hot, warm, and cold. For example, subatomic particles known as neutrinos have been nominated to form hot dark matter, bringing it closest to the realm of ordinary matter. Warm dark matter is thought to exist as “brown dwarfs,” objects that are too small to light up via thermonuclear reactions the way ordinary stars do.
On a more solid footing, the consensus today holds that cold dark matter is composed of weakly interacting massive particles (WIMPS), which are heavy and slow-moving. The aptly named WIMPS interact via gravitation and the weak force alone. They would be completely hidden were it not for their distribution over the whole universe and the large proportion of total matter they constitute, exerting a powerful gravitational force.
Dark energy is considerably more exotic and seems to be vastly more present. Whereas dark matter, although unseen, still influences the visible universe via its gravitational pull, dark energy acts as antigravity, pulling the universe apart at large scales (e.g., beyond the scale of galaxies and clusters of galaxies). How this actually takes place, and providing a theoretical explanation, is no small mystery. Even for it to exist requires precise measurements of how fast the galaxies are accelerating away from one another. According to how many stars you take into account—the key ones are very distant supernovas—the value for dark energy shifts considerably. Some skeptics challenge whether the galaxies are accelerating at all, which would undercut dark energy completely. But cold dark matter with dark energy is currently taken to be the standard model of cosmology. We supposedly inhabit a flat universe, dominated by dark energy, with smaller amounts of dark mass and even smaller amounts of luminous, or ordinary, matter.
From another viewpoint entirely, darkness could be a case of how we observe the universe rather than what it really is. The giant particle accelerators that blast subatomic particles into view operate on the tiniest scale, mere billionths of a meter and billionths of a second. Is that kind of observation compatible with the effect of dark matter, which operates on the largest scale, billions of light-years in size? Before anyone can answer yes or no, one has to challenge if what we see today is the same as what existed long ago. Almost certainly it isn’t. The acceleration that is making the galaxies fly apart faster and faster began very late in the game, roughly 6 billion years ago. Before then, cosmologists believe that the expansion was actually decelerating. That’s because dark matter and dark energy evolve differently in an expanding universe. When the early universe doubled in volume, dark matter density was halved, but dark energy density remained (and remains) constant. When the balance tipped in favor of dark energy, deceleration turned to acceleration.
The “We haven’t even started yet” camp is bolstered by gaps in the standard model. What would it take for totally new thinking to take hold? The journey begins with the psychological aspect of reality, which von Neumann called essential. Seconding him are an array of eminent physicists from the beginning discoveries the quantum era. Max Planck was adamant that reality at bottom involves consciousness. As he put it, “All matter originates and exists only by virtue of a force. We must assume behind this force the existence of a conscious and intelligent mind. This mind is the matrix of all matter.”
This means that lumps of matter are no longer floating “out there” like snowflakes that fall from the sky and collect on your coat collar, but rather, matter is embraced in the same matrix that holds thoughts and dreams. Planck’s belief that mind is even more basic than matter is expressed with total clarity here: “I regard consciousness as fundamental. I regard matter as derivative from consciousness….Everything that we talk about, everything that we regard as existing, postulates consciousness.”
If you’re looking for totally new thinking, it’s been around awhile. What was lacking was acceptance, so let’s build some.
REALITY IS A MIND GAME
Pioneers are bold almost by definition. But what made Planck join Schrödinger in his staunch belief that the universe is mind-like? It goes back to a fact almost too basic to need stating, namely, that everything we experience is an experience. Does this actually tell us anything? Burning your tongue on hot coffee is obviously an experience, and so is building the New Horizons space probe, launching it with a huge missile so that it travels at 36,000 miles per hour through space (boosted to 47,000 mph as it receives a boost swinging around Jupiter), waiting nine years for it to journey almost 6 billion miles to Pluto, and then sending up a cheer, as astronomers did on July 14, 2015, when New Horizons sent back the first close-up photos of the last major body in the solar system.
Burning your tongue and photographing Pluto stand on equal footing as experiences; and doing any kind of science is also an experience. So Planck was asserting that this fact counts—all the time and very deeply. If you can level things as different as the smell of a rose, the blast of a volcanic explosion, a Shakespeare sonnet, and a space probe, then the “matrix” of reality is no longer physical. This offers a tremendous advantage when you reach the dead end that physical “stuff” has reached. The simplicity of turning to a totally new paradigm is that darkness no longer has to be considered alien. The matrix has no trouble including it, because all the stuff in the universe has become mind-stuff.
Here the physicalists shove their oar in. Making solid objects vanish is child’s play compared with bringing them back again. How does mind-stuff, which has no mass or energy, manage to create mass and energy? The matrix that Planck calls consciousness is nothing more, the physicalists might claim, than the universe with all its mysteries unsolved. Sticking on the tag “consciousness” doesn’t really produce any answers. (This skeptical attitude has been paraphrased as “What is matter? Never mind. What is mind? Doesn’t matter.”) In the spirit of fairness, the two camps face equal but opposite difficulties. One must show how the material universe developed the phenomenon of mind, while the other must show how the cosmic mind manufactured matter. At first blush, we’re back in the big muddy of theology, which failed to answer how God did either one.
THE OBSERVER PROBLEM POKES ITS HEAD UP
John von Neumann, having included a psychological component in his version of quantum mechanics, seems to have a foot in both camps. But it’s a shaky place to stand. Let’s say that he was right and reality cannot be separated from personal experience. This doesn’t explain how an experience dips into the quantum level. There’s no doubt that subjectivity is a powerful force for altering reality. As humorist Garrison Keillor says on his popular radio show, Prairie Home Companion, “Well, that’s the news from Lake Wobegon, where all the women are strong, all the men are good-looking, and all the children are above average.” That’s subjectivity overriding reality. But it’s another thing to hold that subjectivity creates reality.
The problem becomes easier if we stop seeing subjectivity as the opposite of objectivity. They are actually merged into each other. The reason we know this is because the subjective side of experience can’t be isolated or subtracted. In other words, when everything is an experience—and everything is—subjectivity must always be present.
Naturally, the physicalist camp resists this claim quite strongly. For a century this great bone of contention has been known as the observer problem. Before it can measure something, science must first observe it. In the classical world, there was no problem observing whatever lay before us: tadpoles, the rings of Saturn, or light being refracted through a prism. One experimenter could leave the room, and no matter who took his place, the observation would remain the same.
The observer is only a problem if the very act of looking creates a change in the thing you are looking at. In the human world we encounter this all the time. If someone gazes at you with love in their eyes, you are very likely to change, and you will change again if the look becomes indifferent or hostile instead. This change can extend very deep, to physical reactions in your body. If you blush or your heart beats faster, the chemistry of your physiology is reacting to a mere look. What makes the observer problem unique in quantum physics is that the act of observation can be enough to bring particles into existence in time and space. This is technically known as the collapse of the wave function, meaning that a probability wave, which is invisible and extends infinitely in all directions, changes state, and suddenly a particle is visible.
One of the basics in quantum mechanics is that a quantum (for instance, a photon or electron) can behave either like a wave or a particle—no one disputes this. What is disputed is whether the simple act of observation causes the wave function to collapse. On the physicalist side, things are things, period, and claiming that an observer causes a particle to emerge from the quantum field is mysticism, not physics. But the most widely accepted version of quantum mechanics, the Copenhagen interpretation (so named after the work done at the Copenhagen Institute by Danish physicist Niels Bohr), places the observer at the crossroads between wave and particle.
This still leaves open the mechanism that allows the act of looking to affect physical matter. Something must be going on under the table, as it were. Observer A looks at Object B with the intention of measuring something about it, such as its mass, position, momentum, and so on. The instant this intention is specified, the object complies—that’s the under-the-table part. No one has an accepted explanation for it. Heisenberg described this in the most definite terms: “What we observe is not nature itself, but nature exposed to our method of questioning.” The observer cannot be separated from the observed, because nature gives us what we want to look for. The whole universe, it seems, is like Lake Wobegon.
Now let’s extend the observer problem, which in the Copenhagen interpretation becomes the observer effect, to the mystery of what the universe is made of. If, as Heisenberg said, “atoms or elementary particles are themselves not real,” then asking what the universe is made of turns out to be the wrong question. We are trying to squeeze juice out of an illusion, and it won’t work. The universe is made of what we want it to show us. Physicalists roll their eyes when they hear such an idea, but certain facts are undeniable. No one has ever seen the wave function collapse—it’s not an observable event—whereas calculating the behavior of matter in terms of uncertainty and probabilities has proved spectacularly successful. Quantum objects defy commonsense rules of cause and effect.
Put these facts together, and the picture that emerges isn’t a cosmos full of “stuff” but a cosmos full of possibilities mysteriously turning into “stuff”—the transformation is more real than the physical appearance we take for granted. To date there is no better answer to “What is the universe made of?” Even a grumbling physicalist has to concede that the collapse of the wave function is a transformation. Pulling a rabbit out of a hat is an illusion; pulling a photon out of the field is real.
Unfortunately for the Copenhagen interpretation (and all of modern physics, no matter which interpretation one favors), the road stops here. An observer in the laboratory may affect the behavior of a photon, but this is miles away from everyday life. Can looking at the whole universe, its stars and galaxies, or looking at trees, clouds, and mountains actually transform them? The notion sounds preposterous at this point, but in fact, this is the basic claim of the human universe. We aren’t there yet. To get around the roadblock, we’ll have to prove that mind isn’t just one factor in the cosmos but the factor that underlies how everything in creation behaves. That challenge is looming ever closer, one mystery at a time.