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52 of 55 people found the following review helpful:
A rival theory to inflation
Not too many people know that there is a theory which is a rival to the inflationary Big Bang and it is, for the time being, completely compatible also with the WAMP satellite findings. This theory is the Cyclic Universe cooked up by Steinhardt and Turok and derived from M theory.
Although the idea of a cyclic universe is already present in some of the...
Published on June 22, 2007 by Jaume Puigbo Vila
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Too many 'maybes' and 'might-be's
I bought this book as a reasonably informed layperson hoping to understand the alternative theory to the Big Bang. After a few pages of this book, my hopes dwindled as I realized this was going to delve more into science fiction than science fact. The entire premise of a recycling or oscillating universe as outlined in this book is based on string theory which is itself...
Published 1 month ago by Tallin
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52 of 55 people found the following review helpful:
A rival theory to inflation, June 22, 2007
Not too many people know that there is a theory which is a rival to the inflationary Big Bang and it is, for the time being, completely compatible also with the WAMP satellite findings. This theory is the Cyclic Universe cooked up by Steinhardt and Turok and derived from M theory.
Although the idea of a cyclic universe is already present in some of the ancient philosophies, this approach differs from previous ones in that it conjectures the existence of two disjoint parts of the universe, two so called "branes" which move to and fro each other along a fourth dimension. This new model avoids the problems Tolman's entropy problem with the classical models which leads to longer cycles.
One way to distinguish experimentally inflation and the cyclic universe is to detect primordial gravitational waves, directly (very difficult) or indirectly (effects of gravitational waves on the polarization of the cosmic background radiation pattern). The inflationary scenario predicts more waves. Some new satellites, already planned or in the drawing boards, may give us an answer to this question in the next ten to twenty years.
Although inflation is at present the standard cosmological paradigm, it has some weak points: creation of the universe about 13,7 billion years out of nothing, the strange inflation field, very strong and very short-lived, etc. The cyclic universe, by postulating an ethernal universe solves the problem of creation and only needs dark energy (no inglation field). In a few trillion years dark energy empties the universe and then the two branes collide and create a new cycle. The authors also claim that, although they did not create their model to solve the cosmological constant problem, an added benefit of the cyclic univers is a relaxing mechanism that very slowly decreases the value of this constant and, at each step, the number of cycles grows exponentially, so that most of the cycles are at a very low value such as the one found today.
The theory also avoids having to make use of the controversial anthropic principle since most of the regions of the cyclic universe can be conducive to life.
Although I learnt quite a few new things by reading this relatively easy to read book, I would have liked a more detailed analysis of the moment of the collision of the two branes. It would seem that at that moment a huge empty space already exists. Does the Big Bang occur locally or everywhere? How far apart can the branes be? It would seem they are very near, but they approach each other once every a few trillion years?
What about the brane we don't see? It seems it has some different properties. If this brane has matter , shouldn't we feel its influence? According to some recent results dark matter is real and is not only the gravitational effect of the other brane.
The book leaves us a little hungry for such answers.
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44 of 49 people found the following review helpful:
Challenging, to say the least, in every way., July 26, 2007
Imagine this as a morning eye opener: "If the extra dimensions start out on a high plateau, they can provide the inflationary energy to drive a powerful burst of inflationary expansion as the roll down to a low-energy state. As they do so, their motion is strongly influenced by quantum jitter." It gets better just a few paragraphs down: "There is nothing unique about the laws of physics, and almost any laws are possible. The universe appears smooth and uniform because astronomers can see only a tiny patch of it: its true wild, random structure on ultralarge scales is unobservable. All of the physical properties of the observable universe are essentially an accident whose history can never be unraveled. Instead of Einstein's dream, the universe is Einstein's worst nightmare."
After you read this book, looking at the night sky will never be the same. Our universe, all those billions of stars, isn't the whole universe according to the author's theory, but only a tiny fraction of a cyclic universe that lasts for a trillion years and starts over again.
One fine day, sometime in the future, there will be a flash and all the particles that make up us and everything will rejoin the cosmos and the cycle begins again.
The inventors of the cyclical universe theory do well at explaining in terms the layperson can, for the most part, grasp, but it is still pretty heady stuff. Helpfully, they provide a glossary that explains terms like "adiabaticity" You can both amaze and baffle your friends as you try to work that one into casual conversation.
Overall, this is a fascinating book, even if difficult to understand. Fun for those with an interest in science, but the general reader would probably not find it attractive.
Jerry
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17 of 17 people found the following review helpful:
Is the universe part of a cyclical Reality?, August 14, 2007
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 objected to the hypothesized final state, as the ultra-dilute universe would effectively be perpetually empty, something he felt to conflict with what we know of reality. I can think of another philosophical objection, namely that we would all look like chumps if we said the world was 6000 years old. Do we really want to be similar chumps who claim that All of Reality began less than 14 billion years ago, less than four times the age of Earth? Isn't it awfully provincial of us to think this way?
The authors also indicate that a cyclical universe would make it easier to put in a way to fine tune the fundamental physical constants we observe. And that's a good point. They propose not a single big bang, but a collision of "branes" which occurs somewhat periodically, producing new universes with different physical laws (or at least fundamental constants) each time (I think the ultimate joke would be if it turned out that remnants of an old universe survived the collision, and that some of the stars that look a little older than 14 billion years are really from a previous universe or an earlier part of the brane collision).
Well, is this cyclical theory coherent? Is it self-consistent? Does it agree with known facts? Does it avoid some old problems (four of which are the entropy issue, the threat of a "mixmaster" universe, the observed acceleration of the universe, and the observed flatness of the universe)? Does it make verifiable "predictions?" Are we really starting with facts and picking a theory that fits them or just picking a theory and looking for facts to support it? The authors basically say yes: the old problems are solved by "extra dimensions, branes, dark energy, and dark energy decay."
In 2006, results from WMAP showed a systematic deviation from perfect scale-invariance. Both inflation and the cyclical model predict this! But there is one more big test to go, and we may know the results in as little as a couple of years. That test is the production of cosmic gravitational waves. A big signal of this sort would support a straightforward inflation model and be inconsistent with the cyclical model. First, of course, we might want to make sure that we can observe gravitational waves at all, and we have some binary stars we can observe to try to do that. Then, perhaps Planck or a later mission will detect (or rule out) such waves.
The authors do like the fact that their model may help solve the issue of the size of the "cosmological constant." And they certainly want to have a multiverse of some sort: "it seems far more plausible that our universe was the result of universe reproduction than that it was created by a unique cosmic event."
I recommend this book. It's readable even for a non-scientist.
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13 of 13 people found the following review helpful:
A Challenging Ride Through a New Model of the Universe, January 3, 2008
Doubtless one of cosmology's greatest mysteries concerns the origins of the universe. What happened at the Big Bang, and how? What precipitated this momentous event? What existed before it, if anything? Was time born at that same instant? Is ours the only universe? Have others existed or exist even now?
Prevailing scientific belief suggests that the universe as we know it began roughly 13 billion years ago with a "point-centered" Big Bang, followed by unimaginably rapid expansion, then enough slowing and cooling to allow the formation of atoms and molecules into planets, stars, and galaxies. In 1997, Lee Smolin's book THE LIFE OF THE COSMOS proposed an alternate theory in which multitudes of universes form at the output ends of black holes, each universe having its own characteristics and unique set of values for its controlling constants. Now, physicists Paul Steinhardt and Neil Turok offer a vastly different theory in THE ENDLESS UNIVERSE.
In a book that challenges its readers' scientific capacity while remaining within a layman's grasp, Steinhardt and Turok eschew the Big Bang singularity for what they term an ekpyrotic or cyclic model. Derived from underlying principles of advanced string theory, they posit our universe as a three-dimensional brane that co-exists with another, mostly parallel brane of more or less equal size. The two branes are separated along an unseen fourth dimension, although the distance of this separation is small and alone among all known physical forces, only gravity can travel this fourth dimension and exert an attractive force between the branes. The authors use this model to posit a trillion-year process in which the branes collide and then separate to their maximum distance apart. During the collision, a birth process for both universes takes place in a manner that looks like the Big Bang. Radiation gradually gives way to matter, allowing stars and galaxies to form, until finally dark matter exerts itself and accelerates the universes' growth and spreads out the galaxies. The branes then become increasingly flat and parallel (as opposed to having been wrinkled but not intersecting as a result of their last collision), allowing the interbrane (gravitational) force between them to begin pulling them back together for another collision.
THE ENDLESS UNIVERSE is loosely divided into three sections. The first section combines a recap of the Big Bang theory and its development during the 20th Century with far less interesting or relevant information about the authors' respective backgrounds, how they met and decided to collaborate, and how their conception of the cyclic model came to pass. Apparently, they failed to see any irony in commingling discussion of the birth of the universe with a full chapter of numbingly trivial personal background and details like, "In August 1981 my wife, Nancy, and I moved with our four-month old baby, Charlie, to Wayne, Pennsylvania, about tweny miles outside of Philadelphia..." Zzzzzzz...Oh, excuse me. What was that baby's name again?
The second section of the book elaborates on the authors' cyclic model, explaining how the branes interact with each other to cause a "big bang" event and how they are influenced by the accelerating expansion of the universe, gravitational effects, and the increasing role of dark matter. Most of the last section of THE ENDLESS UNIVERSE is taken up with discussions of the various technologies being employed to test the Big Bang and cyclic theories. These chapters are some of the most interesting parts of the book, since they offer a fascinating if complicated view of the intersection between cosmological theory and astrophysical oberservation.
Excepting the authors' space-filling personal stories, the bulk of THE ENDLESS UNIVERSE presents an exciting theoretical proposition in one of Science's most exciting fields of theoretical endeavor, the question of what is the universe and where did it come from. Readers will need to make an effort to absorb this material, but they will be rewarded with a fascinating ride through current cosmological thought and experimental efforts at confirmation.
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10 of 10 people found the following review helpful:
Clearly written new theory, August 2, 2007
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.
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8 of 8 people found the following review helpful:
Simply put, a GREAT read for the layperson or the armchair cosmologist!, June 23, 2007
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
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14 of 17 people found the following review helpful:
Accepting infinity..?, January 11, 2008
No matter how long, deep and hard we dwell on existence of the Universe, it is impossible to avoid concept of infinity. What (or Who) is able to be eternal? If this is God, then not Universe. If Universe is such, then there is no need for God. Interestingly authors briefly muse about it in the middle of the book. Saying this and taking theology/philosophy aside I highly appreciate the huge effort taken by both scientists to present their quite stunning, and as for today, extravagant theory - theory challenging inflation. It was easier for me to comprehend Inflationary models (for example in Vilenkin's "Many Worlds in One"). Endless Cycling model is by far the most difficult one, since it is based on String Theory and assumption of extra dimensions. Part of the book evaluates supersymmetry vs. simple string theory in particle physics. Most of the time we read about advantages of Ekpyrotic (Cycling) Universe theory when compared to Inflationary models. Swinging back and forth (in a bit of chaotic and repetitive manner ) authors drill voraciously in systematic fashion all possible holes in the Guth/Linde's Inflationary as well as in Susskind's Landscape and Vilenkin's Multiverses models. And how dedicated, convinced, passionate, determined and eloquent they are!! Though certain fragments are truly exhausting (for example: how colliding branes convert one type of energy to another), numerous repetitions and attempts to emphasize how things happen, are actually often helpful. What has been planted in my head is that: extra "D" + branes + dark energy + potential energy related "spring-like" force between the branes = ekpyrosis. Be it. The final judge deciding which model represents true reality appears to be gravity. Authors list number of proposed and being in progress projects aiming at DETECTING gravitational waves. Unfortunately we will not be able to do so in the next decades, especially if it comes to very weak inflationary waves. However detection is not a single dilemma. We still cannot EXPLAIN the essence of gravity and I did not find anything related to it in this book. Physicists sometimes talk about a concept known as "Mach's Principle", but that principle has never been successfully developed and fails to explain apparent instantaneous action-at-a-distance. In the end comes the last strong punch: Cyclic Ekpyrotic model is free of Anthropic Principle dilemma!! It is very important to cosmology to have competing models and unanswered lingering questions about their validity. In general: very brave and colorful popular science book, recommended for curious and following "strange" cosmology ideas readers.
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18 of 23 people found the following review helpful:
Endless debate on cyclic theory and inflation theory, July 4, 2007
I am not a professional cosmologist or physicts. I found this book is interesting and it is easily understood by layman like me. I must confess that I do not understand the String M-Theory, Braneworld and inflationary theory clearly. I cannot give a fair judgment about Cyclic Theory and Inflation Theory. Since both the universe past and future is far way from us and they are not reliable to justify the validity of inflation theory and cyclic theory. Since there are no empirical data to distinguish the merits of inflations theory and cyclic theory. Both theories is more or less like science fiction. If the extra dimension between 2 branes are as "large" as Paul and Neil suggests in the book. Cyclic theory may have strong experimental data which support Cyclic theory is right. But no matter which theory is correct, Paul Steinhardt and Neil Turok has clearly tell all the reader why cycle theory is possible and excisting, why START and END of time is important. Personally I found the explanation of inflation theory is very excellent and I recommand any reader to read carefully the inflation explanation, cyclic theory explanation, problem on the start and end time.
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7 of 8 people found the following review helpful:
What do you want from a cosmology book? This has it all., October 10, 2007
What is it? Science history? The best description on particle cosmology, Higgs fields, string theory and M theory? Hard science? Easy to understand for non-physicists? Fluid, descriptive and iconic language? Insight into developing theories? Far-out but scientific plausible ideas? Whatever it is, this book has it all! In my opinion it is better written and more interesting than most other books in its field, even from books by the most well known (for popular book publishing) scientists. Very highly recommended.
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2 of 2 people found the following review helpful:
The universe you always wanted, May 1, 2009
This was another one of those books which, like The Cosmic Landscape by Leonard Susskind, I could not put down once I began reading it. That is not necessarily a compliment, for such books can really mess up one's schedule. I found this book to be less well-written than Susskind's book but somewhat more reasonable in its speculations. While I have decided to tentatively abandon my "turtles-all-the-way-down" cosmology for this ekpyrotic model, I cannot say that this new model will make too much difference in terms of the way I see the world, or my existence in it. The one possible exception to that would be that I've begun to think of the universe as being maybe more like a quintillion years old instead of just a measly 14 billion. In all fairness, however, if you believe in Eternal Inflation, then the multiverse could also be at least as old as the ekpyrotic model. I do believe that thoughtful people do need to have some models available to them to conceptualize what "there" might have been "before" the big bang.
The authors do an excellent job of explaining the anthropic principle. Susskind wrote about this principle as well, but to my mind never explained it very well. The authors dismiss the anthropic principle as being unscientific, and so perhaps it is. However, the anthropic principle cannot be easily dismissed. It may be more philosophical than scientific; still it must be reckoned with. It must be confronted head-on. Certainly, there are degrees of anthropism. The ekpyrotic model can be criticized as being somewhat anthropic: Here we have a cyclic universe which just happens to be tailor-made for us to live in. And every single cycle seems to be exactly fit for us to live in. Later in the book, one of the authors confesses that the cosmological constant could also be modeled as varying ever so slightly over each cycle. This somewhat diminishes the anthropic quality of their model.
The ekpyrotic model can also be criticized as being just a little too elegant: The way in which they have their model avoid violating the second law of thermodynamics is a tad too clever to my mind. The authors also try portray their model as being more "reassuring" to the ordinary person-in-the-street, in that you don't have to lie awake at night worrying about the universe disintegrating into Nothingness eventually; there will always be another cycle to look forward to. But the Long Run is a trillion years, and that is no parenthesis. While it is considerably more elegant than the Cosmic Landscape, it still, like that dreaded model, presents us with a future completely dominated by dark energy and increasing isolation.
One possible benefit of reading this book is to be able to come back to the model in ten or fifteen years hence (if our planet is still around) to see how it has gotten more mature, less elegant, less cute; in short, how it has evolved and grown up. Clearly, this model is still evolving. Overall, this was a book whose ideas will resonate for a long time after reading it. I loved it!
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