). He begins with a chapter describing the three revolutions in cosmological thought. The Ptolemaic picture of the universe, dating from the second century of the Christian era, was challenged by Copernicus and Galileo in the 16th and 17 centuries—this challenge Seife calls “The First Cosmological Revolution.” “The Second Cosmological Revolution” was the one begun by Edwin Hubble in the 1920s, showing that the objects we see in the sky that used to be called “nebulae” and thought a part of our own galaxy are really other galaxies, all receding from us at speeds relative to their distances. This second revolution leads to a theory about the beginning of the universe in the Big Bang and an estimate about the universe’s age. By 1965, the cosmic microwave background or cosmic background radiation left over from the Big Bang had been discovered.
The third revolution began with various teams of astronomers using supernovae to try to get an accurate reading of the Hubble constant—the speed at which the universe is expanding—and how it might have changed through time. By 1998, there was general agreement among these teams that the universe’s expansion was speeding up, not slowing down as everyone had thought. There has to be some repulsive or antigravitational force to explain this accelerated expansion. In effect, there has to be a great deal more energy in the universe than can be accounted for by conventional means. We already knew we had a similar problem with matter: in the 1970s Vera Rubin showed that star movement at the edges of galaxies proved that these galaxies must contain much more matter—called dark matter because it doesn’t show up as stars or in any other visible form—than could be measured. The universe seems to be mostly composed of dark energy and dark matter. Seife succeeds in conveying how monumental these developments are, and how tantalizingly close we seem to be to answering the questions that have been raised in this third great overturning of common wisdom about the universe.
Astrophysics connects with subatomic physics because as we go back toward the Big Bang, we go past the phase where matter coalesces into atoms to a point a few microseconds into the life of the universe when the protons and neutrons that form atoms are not themselves yet formed from their constituent quarks. These sub-subatomic particles have distinctive qualities that are named metaphorically: six flavors (up, down, strange, charm, bottom, and top), a positive or negative spin and one of three colors: red, blue, or green. Baryons—heavy particles such as protons and neutrons—are always made up of three quarks, one of each color, canceling the color in the heavy particle. There are also gluons that make quarks stick together. This section of the book challenges the reader more than any other, but Seife works hard to explain his concepts with common examples at the same time as he is obviously working hard not to oversimplify the concepts themselves.
To try to make a quark-gluon plasma such as must have preceded the formation of subatomic particles in the early universe, scientists use huge particle accelerators such as that near Geneva and the Heavy Ion Collider at Brookhaven in New York. Subatomic investigations are attempting to answer several questions of the astrophysical variety: Can subatomic physics tell us where all that matter and energy is hiding? Can it tell us why there is any matter at all, since antimatter particles, if there were equal numbers of them as some theories seem to demand, would have annihilated all the matter particles? Why, in other words, were there more matter than antimatter particles in the early universe?
Sixteen fundamental particles make up the “standard model” of subatomic physics. Six are quarks of different flavors; combined in various ways these make up heavy particles (baryons) and middle-weight particles (mesons). Six are leptons or light-weight particles: the electrons, muons, and the very rare tau particles are all charged, and for each there is a neutrino with the corresponding charge. Moreover there are four force-carrying particles that make for interactions: the photon, the gluon, the W boson and the Z boson. Bosons carry the weak force, which has the ability to change a neutron into an electron or change the flavor of a quark, and the difference is that Ws are charged and Zs are not.
The investigations that arrived at the standard model found a few answers; one is that neutrinos have mass and in fact represent as much of the universe’s mass as the visible baryonic matter of stars and galaxies. But there’s still a good deal of baryonic matter unaccounted for (baryonic dark matter) and much more of the exotic dark matter whose make-up we don’t know. The only way the standard model can be stretched to try to account for the exotic dark matter is by theorizing that each particle in the model has a twin--the theory is known as supersymmetry.
Meanwhile, astronomers are using new tools to try to find the ordinary baryonic matter that’s hiding. The effect massive objects have of bending light—gravitational lensing—is being used to find small objects of great mass in our galactic surroundings: massive compacts halo objects or MACHOs are part of the ordinary baryonic dark matter of the universe.
The orbiting Chandra X-ray Observatory is being used to look for exotic dark matter, and so are the huge, buried neutron detectors, which may also detect a weakly interactive massive particle, or WIMP, possibly the first supersymmetric particle that will be observed. One point of investigation as a source of dark energy is the vacuum, which is not really empty, but contains particles that, on very small time scales . . . are constantly blinking in and out of existence.” The latent energy in the vacuum is probably connected to the early inflation of the universe that, some physicists theorize, actually happened faster than the speed of light.
In the 1960s and 1970s, the first pulsars and binary pulsars were found. Pulsars are tiny neutron stars that emit powerful radio waves as they spin; a binary pulsar is a pulsar orbiting another, unseen star. These discoveries led to a demonstration, in the minute slowing of orbiting pulsars, that they were losing energy. General relativity predicted that the lost energy was in the form of gravitational waves. Theoretically, gravitational waves resulting from the birth of the universe should be still detectable. Scientists are looking for them in two ways: linked laboratories in Washington and Louisiana known as LIGO—the Laser Interferometer Gravitational Wave Observatory—opened in 2000, and a flying laboratory consisting of three spacecraft in formation and known as LISA—the Laser Interferometer Space Antenna—will be launched in 2008. A laboratory in Antarctica, meanwhile, is measuring the polarization of the light left over from the Big Bang. All of these projects and others that have already and will in the future measure aspects of the cosmic background radiation—its microwave intensity and variations, its gravitational waves, and its polarization—give information about the origin of the universe.
In the last chapter, Seife writes about some of the theories physicists have come up with to try to reconcile quantum mechanics and general relativity, the great challenge at the beginning of the twenty-first century. Einstein tried and failed. Theories have been advanced that look at particles as membranes in eleven-dimensional space (“M-theory”), or look at quanta changes in subatomic particles as “choices” in one of many simultaneous universes (the “many worlds” hypothesis); but no experimental scenario could now be devised to test these theories. But, as Seife concludes, we now know pretty much how the universe began, what it’s made of, and how it will end. By the end of this decade, he predicts, we will have fuller answers, especially about dark matter and dark energy, the vacuum, and the question why there is more matter than antimatter.
Seife includes several appendices, one listing recent Nobel prizes in physics and predicting the next likely ones, another providing a glossary of the terms he introduces earlier in the book. There’s a bibliography and a good index. ( )

Popular-level but authoritative account of discoveries in cosmology's golden age (which we are privileged to be in the middle of).

This book is similar to "A Brief History of Time" in so far as the subject matter is concerned. However, it does deal more with the historical myths of the Beginning and End of the universe, which Hawking doesn't really talk about. I also feel that this book gave clearer explanations of many things. Perhaps it was just easier to understand because it was written by a journalist rather then a super genius ;)

Over all, an excellent book. ( )