The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality

by Richard Panek

An exciting look at the next big thing in cosmology--the search for dark matter and dark energy--and the making of an entirely new physics.

  • Format: Paperback
  • ISBN-13/ EAN: 9780547577579
  • ISBN-10: 0547577575
  • Pages: 320
  • Publication Date: 10/18/2011
  • Carton Quantity: 24

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About the Book
About the Author
  • About the Book

    “Fascinating . . . One of the most important stories in the history of science.”— Washington Post

    In recent years, a handful of scientists has been racing to explain a disturbing aspect of our universe: only 4 percent of it consists of the matter that makes up you, me, and every star and planet. The rest is completely unknown.
    Richard Panek tells the dramatic story of how scientists reached this cosmos-shattering conclusion. In vivid detail, he narrates the quest to find the “dark” matter and an even more bizarre substance called dark energy that make up 96 percent of the universe. This is perhaps the greatest mystery in all of science, and solving it will bring fame, funding, and certainly a Nobel Prize. Based on hundreds of interviews and in-depth, on-site reporting, the book offers an intimate portrait of the bitter rivalries and fruitful collaborations, the eureka moments and blind alleys, that have redefined science and reinvented the universe.

    “A lively new account of twentieth-century (plus a little twenty-first-century) cosmology . . . The book is as much about how the science got done as about the science itself.”—Salon

  • About the Author
  • Excerpts


    The time had come to look inside the box. On November 5, 2009, scientists at sixteen institutions around the world took their seats before their computer screens and waited for the show to begin: two software programs being run by two graduate students — one at the University of Minnesota, the other at the California Institute of Technology — simultaneously. For fifteen minutes the two scripts would sort through data that had been collecting far underground in a long-abandoned iron mine in northern Minnesota. Over the past year, thirty ultrasensitive detectors — deep-freeze cavities the size of refrigerators, shielded from stray cosmic rays by half a mile of bedrock and snug blankets of lead, their interiors cooled almost to absolute zero, each interior harboring a heart of germanium atoms — had been looking for a particular piece of the universe. The data from that search had sped from the detectors to offsite computers, where, following the protocol of a blind analysis, it remained in a “box,” out of sight. Just after 9 a.m. Central Time, the “unblinding party” began.
     Jodi Cooley watched on the screen in her office at Southern Methodist University. As the coordinator of data analysis for the experiment, she had made sure that researchers wrote the two scripts separately using two independent approaches, so as to further ensure against bias. She had also arranged for all the collaborators on the project — physicists at Stanford, Berkeley, Brown; in Florida, Texas, Ohio, Switzerland — to be sitting at their computers at the same time. Together they would watch the evidence as it popped up on their screens, one plot per detector, two versions of each plot.
     After a few moments, plots began appearing. Nothing. Nothing. Nothing.
     Then, three or four minutes into the run, a detection appeared — on the same plots in both programs. A dot on a graph. A dot within a narrow, desirable band. A band where all the other dots weren’t falling.
     A few minutes later another pair of dots on another pair of plots appeared within the same narrow band.
     And a few minutes later the programs had run their course. That was it, then. Two detections.
     “Wow,” Cooley thought.
     Wow, as in: They had actually seen something, when they had expected to get the same result as the previous peek inside a “box” of different data nearly two years earlier — nothing.
     Wow, as in: If you’re going to get detections, two is a frustrating number — statistically tantalizing but not sufficient to claim a discovery.
     But mostly Wow, as in: They might have gotten the first glimpse of dark matter — a piece of our universe that until recently we hadn’t even known to look for, because until recently we hadn’t realized that our universe was almost entirely missing.

    It wouldn’t be the first time that the vast majority of the universe turned out to be hidden to us. In 1610 Galileo announced to the world that by observing the heavens through a new instrument — what we would call a telescope — he had discovered that the universe consists of more than meets the eye. The five hundred copies of the pamphlet announcing his results sold out immediately; when a package containing a copy arrived in Florence, a crowd quickly gathered around the recipient and demanded to hear every word. For as long as members of our species had been lying on our backs, looking up at the night sky, we had assumed that what we saw was all there was. But then Galileo found mountains on the Moon, satellites of Jupiter, hundreds of stars. Suddenly we had a new universe to explore, one to which astronomers would add, over the next four centuries, new moons around other planets, new planets around our Sun, hundreds of planets around other stars, a hundred billion stars in our galaxy, hundreds of billions of galaxies beyond our own.
     By the first decade of the twenty-first century, however, astronomers had concluded that even this extravagant census of the universe might be as out-of- date as the five-planet cosmos that Galileo inherited from the ancients. The new universe consists of only a minuscule fraction of what we had always assumed it did — the material that makes up you and me and my laptop and all those moons and planets and stars and galaxies. The rest — the overwhelming majority of the universe — is . . . who knows?
     “Dark,” cosmologists call it, in what could go down in history as the ultimate semantic surrender. This is not “dark” as in distant or invisible. This is not “dark” as in black holes or deep space. This is “dark” as in unknown for now, and possibly forever: 23 percent something mysterious that they call dark matter, 73 percent something even more mysterious that they call dark energy. Which leaves only 4 percent the stuff of us. As one theorist likes to say at public lectures, “We’re just a bit of pollution.” Get rid of us and of everything else we’ve ever thought of as the universe, and very little would change. “We’re completely irrelevant,” he adds, cheerfully.
     All well and good. Astronomy is full of homo sapiens–humbling insights. But these lessons in insignificance had always been at least somewhat ameliorated by a deeper understanding of the universe. The more we could observe, the more we would know. But what about the less we could observe? What happens to our understanding of the universe then? What currently unimaginable repercussions would this limitation, and our ability to overcome it or not, have for our laws of physics and our philosophy — our twin frames of reference for our relationship to the universe?
     Astronomers are finding out. The “ultimate Copernican revolution,” as they often call it, is taking place right now. It’s happening in underground mines, where ultrasensitive detectors wait for the ping of a hypothetical particle that might already have arrived or might never come, and it’s happening in ivory towers, where coffee-break conversations conjure multiverses out of espresso steam. It’s happening at the South Pole, where telescopes monitor the relic radiation from the Big Bang; in Stockholm, where Nobelists have already begun to receive recognition for their encounters with the dark side; on the laptops of postdocs around the world, as they observe the real-time self-annihilations of stars, billions of light-years distant, from the comfort of a living room couch. It’s happening in healthy collaborations and, the universe being the intrinsically Darwinian place it is, in career-threatening competitions.
     The astronomers who have found themselves leading this revolution didn’t set out to do so. Like Galileo, they had no reason to expect that they would discover new phenomena. They weren’t looking for dark matter. They weren’t looking for dark energy. And when they found the evidence for dark matter and dark energy, they didn’t believe it. But as more and better evidence accumulated, they and their peers reached a consensus that the universe we thought we knew, for as long as civilization had been looking at the night sky, is only a shadow of what’s out there. That we have been blind to the actual universe because it consists of less than meets the eye. And that that universe is our universe — one we are only beginning to explore.
     It’s 1610 all over again.

  • Reviews
    "The centerpiece of The 4% Universe is a compelling narrative of science at its best… serve[s] handsomely as an illuminating guide to the dark mysteries lying at the heart of the intersection of astronomy and fundamental physics."
    The Wall Street Journal

    "Impeccably researched and highly readable."
    New Scientist

    "A remarkable book and a model for all would-be popular-science writers."
    Physics World

    "Panek's passion for the mysteries of dark matter and dark energy wins the day. He succeeds because he recognizes that he's writing not just about red shifts and supernovae, but about people...the success of The 4 Percent Universe also stems from Panek's wisdom about how science works."
    The Washington Post

    "The balance between lively characters and provocative ideas keeps the book moving as quickly as any high stakes thriller, but the pay-off here is an answer of truly cosmic significance...the universe is keeping secrets from us--big secrets. Dark secrets. Panek's joyful journey through the wilds of modern cosmology gives us good reason to care about those secrets, and their sure-to-be surprising answers."
    Ad Astra, Magazine of National Space Society

    "A superior account of how astronomers discovered that they knew almost nothing about 96 percent of the universe. Science writer Panek (The Invisible Century: Einstein, Freud, and the Search for Hidden Universes, 2005, etc.) points out that 50 years ago astronomers assumed they understood the cosmos and its history from the big bang to galaxy formation to its ultimate fate as expansion continued. One detail remained disturbing: Galaxies were moving too fast. Since gravity controls movements, they had to be heavier than predicted. By the 1980s, this "missing mass" problem became critical as it became clear that galaxies, including ours, were rotating so fast that missing mass far outweighs visible objects such as stars. Even after eliminating gas and dust, "dark matter" represents strange particles unknown to science. Astronomers also believed that gravity was slowing expansion of the universe but debated if galaxies would reverse themselves, continue to recede ever more slowly or (the favorite theory) simply stop. Panek describes frustrating struggles with high-tech detectors, complex computer algorithms and massive telescopes to search distant galaxies for the key. The answer came in the late '90s expansion wasn't slowing but speeding up. Flabbergasted astronomers understood that accelerating billions of galaxies requires immense energy. Since Einstein proved that energy and mass are equivalent, this "dark energy" makes up three-quarters of the universe. Dark energy added to dark matter reduces the familiar universe to 4 percent of the total. Panek delivers vivid sketches of scientists, lucid explanations of their work and revealing descriptions of the often stormy rivalry that led to this scientific revolution, usually a media cliche, but not in this case." 
    —Kirkus Reviews, STARRED review

    "There has always been more to the universe than we can see. Science journalist Panek (The Invisible Century) offers an insider's view of the quest for what could be the ultimate revelation: the true substance of the unseen dark matter and energy that makes up some 96% of our universe. The search for these hidden elements began in the 1960s with astronomers asking whether the universe would end in an infinitely expanding "Big Chill" or a collapse into a "Big Crunch"--or whether the universe is a just-right "Goldilocks" space that would nurture stars and galaxies forever. To answer this question, scientists calculated the universe's mass and discovered there was far more mass than we could see. But where is this "missing mass" and what kind of exotic "dark" stuff is it made of? Panek gleefully describes a 'Wild West of the mind, where resources were scarce, competition was fierce, and survival depended on small alliances of convenience, often enduring just long enough to publish a paper.' This lively story of big personalities, intellectual competitiveness, and ravenous curiosity is as entertaining as it is illuminating."
    —Publishers Weekly, STARRED review

    "The 4% Universe is a lively and well-researched account of the personalities and ambitions of modern scientists." 
    —Alan Lightman, author of Einstein’s Dreams

    "Somebody needed to tell this story—of all that is dark and mysterious in the cosmos. Science writer Richard Panek has risen to that task. In his journalistic yet artful style, Panek guides you through the quirky discoveries that established the existence of dark matter and dark energy. But along the way, you also get to meet the quirky cosmologists who got us there."
    —Neil deGrasse Tyson, American Museum of Natural History, author of Death by Black Hole

    "A contemporary adventure story of modern-day explorers who venture forth into the universe not by ships, but by telescopes and satellites. . . . Riveting."
    —Lee Smolin, author of The Trouble with Physics

    "It’s the biggest mystery of all: why is the universe expanding at an accelerated rate? At its heart is a search for what forces and particles make up reality. It baffled Einstein, and it now obsesses a cadre of fascinating cosmologists. By brilliantly capturing their passions and pursuits, Richard Panek has made this cosmic quest exciting and understandable."
    —Walter Isaacson, author of Steve Jobs and Einstein: His Life and Universe  "The 4% Universe is a reliable and readable account of how scientists discovered—and are struggling to come to grips with—the astounding fact that most of the observable universe has not yet even been observed, much less understood. It has the further merit of relating how scientists arrive at their findings, rather than simply presenting their theories as objects of admiration or adoration. Highly recommended."
    —Timothy Ferris, author of Coming of Age in the Milky Way and The Science of Liberty

    "Modern cosmology tackles some of the biggest questions we have about the nature of the cosmos. In The 4% Universe, Richard Panek brings this quest down to a human scale. The rivalries, the surprises, and the excitement are brought vividly to life. People are a very tiny percentage of the universe, but we remain the most interesting part."
    —Sean Carroll, author of From Eternity to Here: The Quest for the Ultimate Theory of Time