Endless Universe: Beyond the Big Bang

This is a very interesting and important book on a major new theory on how the world began. Two prominent players in physics and cosmology (Steinhardt of Princeton and Turok of Cambridge) lay out in a very readable popular science book a fundamentally new theory, which started as the Ekpyrotic universe (terrible name) in 2001 and has evolved into the cyclic universe, a theory that challenges the prevailing big bang theory. The big bang theory in its current form envisions a multi-universe with endless space of which our universe is only a tiny part. The cyclic model envisions repeating versions of a single universe spread out over endless time. In a loose sense the new theory is a 'dual'(engineering term) of the big bang with endless time replacing endless space. If looked at in isolation, the new theory looks quite bizarre ( & crazy) because it comes out of a specific string theory model with 'branes' (membranes) living in hidden extra dimensions. A lot of physicists love string theory because of its elegant mathematics and the hope it will merge merging quantum mechanics and gravity, but there is not a shred of experimental evidence supporting it. Roger Penrose (on the dust jacket) advises readers who are skeptical of string theory to "suspend such views" and read this book, adding, "It may well be closer to truth than you think." Also on the dust jacket are praise from Stephan Hawking, Martin Rees, and Brian Greene. Steinhardt admits this theory is a little crazy, but as Roger Penrose says, "Perhaps we need a crazy theory to address these things". The authors do a good job showing that the prevailing big bang theory has over the last thirty years acquired its own considerable baggage and is now pretty weird too. Some textbook big bang models are in fact now known to be invalid, ruled out by high resolution data on the cosmic background radiation from the WMAP satellite. The current big bang theory implies eternal inflation and a multi-universe in which we just happen to live in a rare bit of space that is livable (anthropic theory). Big bang needs two types of unseen energy, inflation energy and dark energy, that are unrelated and both carefully tuned. In the cyclic universe theory the horizon, flatness and monopole problems are all solved without the need of inflation, hence no inflation energy, dark energy does both jobs. One indication they might be on the right track, they argue, is that they didn't construct the theory around dark energy; its ability to solve two problems came as a sudden later revelation that is recounted in the book. Each cycle, which they estimate is about a trillion years, starts with a quasi-big bang, but it is not a singularity (temperatures are not infinite), so conditions are in principle calculable. The initial energy of the hot radiation comes from the kinetic energy of branes which moving toward each other and colliding in an unseen dimension. The authors emphasize that all five experimental tests curr

I enjoyed it quite a bit. The circular universe theory is very well explained to a person who is not into physics day to day. Having some background in physics (such a good high school or college physics course helps). I disagree with some of the other reviewers about the personal stories of the authors. I believe it's important to describe how the authors got where they are today. Discussion of philosophical implications of the theory and some of the historical philosophers and theologists who shared the same idea was quite interesting.

Is Reality, including the visible universe, something which is roughly steady-state, obeying the same physical laws with about the same fundamental constants? Or is it simply expanding, with an initial time around 14 billion years ago? Or is it somehow cyclical? Or is it a "multiverse" in some other manner? This excellent popular book addresses these sorts of questions. And it is written by a couple of superb theoreticians who have some interesting ideas on the subject. In addition, it takes into account the latest results of WMAP, released just last year. Steinhardt and Turok start with a funny quote from the silly spoof "The Restaurant at the End of the Universe," in which Douglas Adams quipped that there was a theory that if we ever figured out what the universe were for, it would immediately "disappear and be replaced by something even more bizarre." And that another theory states that this has already happened. And the model of Reality that Steinhardt and Turok propose may be a little closer to this than one might have imagined. As the authors explain, a century ago, there was no strong evidence against a steady-state universe. And even the Hubble expansion, discovered around eighty years ago, could still have been consistent with such a model. But that expansion also suggested an alternative idea, namely expansion from a very dense and hot initial state. Although the authors do not get into this, the amounts of helium and isotopes of other light elements were shown to be remarkably consistent with the nucleosynthesis expected from that hot and dense initial state. And as the authors do say, the discovery of the cosmic background radiation got most folks to agree that the temperature and density of the universe were indeed very high at some point (probably around 14 billion years ago). There were some problems associated with this model of the universe. These included the surprising homogeneity and flatness of the universe we observe as well as the lack of magnetic monopoles. The first two of these problems seemed to me even more fundamental than the third. All three can be solved, however, by a concept known as "inflation," in which the universe expands greatly very early in its history, well before the first nanosecond is complete. That, however, leads to a possible model that rubs some folks the wrong way. It seems to be saying that Time and Space began around 14 billion years ago. There may be many "bubbles" in which there are universes that look very different from ours. But our universe would then expand forever, and that would be it. The authors point out that some philosophers do not like a universe which originates from nothing (actually, that in a way does not bother me, given that the physical laws we see could well cause such an event to occur, with a quantum fluctuation of the vacuum producing something about the size of the "big bang"). They also point out that Einstein made it clear he would have

As one who has read many of these popularized physics book, I would rate this one at the top. Without one equation, it is written in a semibiographical way that shows how physicists carry out their work. It captures the excitement of the development of the new "Cyclic Universe" theory that the authors cooperatively developed to counter the current favorite Big Bang- Inflation theory. The new theory incorporates the new theories in physics: M theory, extra dimensions, formation of matter and explains all data from the WMAP measurement of the background radiation as well as the Big Bang model. But, the new theory has the advantage of not requiring a beginning nor does it need to bring in the Anthropic principle to explain fine tuned constants. The new theory differs from previous cyclic models in that it doesn't rely on the amount of matter in the universe to shift the expansion to a contraction. It instead posits that dark energy changes over time and dominates the cycles and the bang is due to colliding branes from M theory. The authors emphasise that physicists don't just make these things up, but they come out of the mathematical theories. There is one prediction of the theory that will distinguish it from the Big Bang. They predict different amounts of gravity waves. Future satellite measurements will be able to prove one theory or the other. As with the authors, I hope the Cyclic theory wins.

This was a wonderful, easy-to-read book, that will be gratifying not only to hard-core cosmologist devotees, but to the layperson who only has a modicum of knowledge regarding cosmology. I would recommend this book to anyone who wants to learn about the latest theories regarding where we are, where we've been, and what will happen to 'everything' in the far future. A great feast for the mind! Ed Reifman