The Fifth Essence
Raymo, Chet
BOOKS It's darker than we thought THE FIFTH ESSENCE The Search for Dark Matter in the Universe Lawrence M. Krauss Basic Books, Inc., $21.95, 342 pp. Chet Raymo In the early 1930s the...
...The search for dark matter takes us to the realm of the galaxies with the largest telescopes on earth, and into the heart of matter with colossal particle-accelerating machines...
...The dark material is located in and around galaxies of every type, including our own Milky Way galaxy...
...Stars too small to ignite their thermonuclear fires...
...Not only are we not at the center of the universe, but the entire visible universe is but a drop in the cosmic sea...
...Nor planets, which in our solar system account for only a tiny fraction of the total mass...
...I said, "Ninety-seven percent of the stuff in the universe is stuff about which we know absolutely nothing...
...Most scientists, and many philosophers and theologians, have long since accepted our spatial and temporal insignificance...
...Many readers will find certain technical parts of the book demanding, but those who perservere will be carried along on one of the great intellectual adventures of our time...
...Certainly, questions about the beginning and end of the universe, and its "essences," are among the most profound that concern the human mind...
...The startling conclusion: Up to 97 percent of the mass of the universe is unseen...
...On the other hand, the mere fact that most of what has weight presently eludes our senses hardly constitutes a revolution on the same scale as that of Copernicus...
...In that sense, at least, we have no farther to fall...
...Certainly not stars, which we should see by their light...
...Lawrence Krauss, a professor of physics and astronomy at Yale University, believes the discovery of dark matter brings us to the brink of the "ultimate Copernican revolution...
...No one yet knows what this invisible matter consists of...
...I once recounted these developments to a friend...
...But what was this mysterious stuff...
...In the time since the galaxies formed, the members of the Coma cluster should have dispersed...
...It is a quest that unites the largest and smallest things in the universe-a quest that leads us back to the universe's fiery beginning and forward to the universe's uncertain end...
...He replied somewhat forlornly, "It is probably the best stuff, too...
...Early in the book, Krauss disassociates himself from "distasteful" attempts on the part of popular science writers "to interest people in modern science by portraying all new developments as intellectually profound...
...Yet the cluster is apparently stable...
...Zwicky's guess was prophetic...
...Black holes...
...If these arguments are correct, then it seems very likely that we, and all that we can see, form an insignificant bit of 'noise'-a cosmic afterthought, so to speak...
...The problem was this: The galaxies are moving faster than the velocities that would allow them to escape the gravitational attraction of the system...
...Massy neutrinos from the creation...
...Something is holding it together...
...Whether life is a "cosmic afterthought," as Krauss claims, or a cosmic forethought remains an open scientific question, but the fact that human life is physically dwarfed by the cosmos is indisputable...
...In almost every case, the pull of gravity is stronger than what can be accounted for by luminous matter...
...How much farther can we fall...
...The entire biomass of earth is negligible compared to the weight of the planet-an insubstantial whiff of matter...
...He measured the relative velocities of galaxies in the Coma cluster of galaxies, and he estimated the total mass of the galaxies in the cluster by adding up all of their luminous matter...
...Chet Raymo In the early 1930s the astronomer Fritz Zwicky made a perplexing discovery...
...Professor Krauss has been a participant in the search for dark matter, and in The Fifth Essence he tells the story with clarity and attention to detail...
...Dark matter may or may not be the "best stuff," but it certainly is disconcerting to discover that most of what exists remains unseen by human eyes and unknown...
...Whatever the dark matter turns out to be, it is certainly unlike anything here on earth...
...However, he does the same thing himself, throughout the book, and perhaps with some justice...
...asks Krauss...
...If the weight of the planet-and all other luminous matter in the universe-is only the tip of the gravitational iceberg, that will hardly alter our view of ourselves...
...Nor gas or dust, which we could detect by either the emission or the absorption of light...
...Astronomers have subsequently observed the gravitational dynamics of many individual galaxies and clusters of galaxies...
...Zwicky guessed that there is more matter in the cluster than meets the eye, dark, non-luminous matter exerting the required gravitational tug to hold the galaxies in place...
Vol. 117 • February 1990 • No. 4
