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Showing reviews 1-5 of 46
 A very interesting book about the properties of reality December 25, 2005
Jill Malter (jillmalter@aol.com)
43 out of 50 found this review helpful
Is this book just what I wanted? Well, what I think I really wanted was for Einstein to return to us today and write a book on the philosophy of modern physics based on today's understanding of things. Yes, that would have been just great! But Einstein is dead. Luckily, of course, there are some excellent physicists around, such as the author of this book.
This book, written by an eminent String Theorist, has some fine explanations for the layman of some topics in modern physics, including String Theory. But the most interesting part is advertised in the title, namely the nature of the cosmic landscape.
The cosmic landscape refers to the mathematical space which has as its elements the values of the "fields" that constitute the physical laws and constants which apply to a particular "universe" (with a small u) or "pocket universe" if one prefers that term. The idea is that there may be many possible sets of physical laws and constants. The more we discover about physics, the more it seems that there are plenty of possible universes. But do they really exist? That is, is the landscape populated by more than our known universe? Is it heavily populated? The author argues that it is. And that certainly makes sense to me.
We're told about the anthropic principle. At its simplest, this principle merely states that we have to live in a universe that permits intelligent life. That's not very profound. But this principle also suggests that there is indeed a landscape of possible universes, and it encourages us to verify that only a very small fraction of them would permit the kind of complexity required for intelligent life. And in fact, Susskind gives us a good example of this. It turns out that the Cosmological Constant (which causes a universal repulsive force, sort of the opposite of gravity) we observe is about 120 orders of magnitude less than an unsophisticated theory might predict. That leaves us with a very tiny number to explain, a number which is fundamental to the laws of our universe. Well, sure enough, there appears to be an anthropic reason. Susskind tells us that Steven Weinberg calculated that a constant even ten times bigger would result in enough repulsion so that the clumpiness of the early universe would have been reduced so much that no galaxies, stars, or planets would have formed. Similarly, a large cosmological constant with the opposite sign would have caused our early universe to collapse.
Given that there may be a large multiplicity of actual universes, how do they originate? Since we appear to be in a rather unusual universe, it is tempting to hypothesize that there's some sort of selection principle at work. But what? We get into questions about a possible evolution of universes. But this could be quite different than evolution in biology. Are there incremental changes between generations of universes, and if so, how? Susskind doubts that changes are incremental. Are there universes that produce large numbers of other universes, given that there are no obvious selection benefits to having fewer offspring? As Susskind says, we see no mechanism to cause competition for resources. Are we in a produced universe, a producing universe, or both? If our universe is a producer, do miscellaneous black holes each produce new universes? Well, according to Susskind, they don't: the production mechanism he suspects is dominant is the cloning of space due to the metastability of the vacuum.
I think it helps to remind ourselves that if there is a large system of pretty much random entitites, that system will be dominated by the biggest ones. If time exists, that system will soon be dominated by not just the biggest, but the most stable and longest-lived ones. And those objects that produce, get produced, or are reproducing (or even better, reproducing in a manner than permits improvements) have a huge advantage. That applies to the Earth's biosphere, and presumably it applies to Reality as a whole.
Susskind discusses the "many-worlds" interpretation of quantum mechanics. In this version, when there is a random choice of polarizations for a particle (or a random choice of which slit a photon traveled through), both possibilities actually occur, but in different aspects of reality! That works mathematically, although it does produce a truly huge number of alternate realities. Susskind does say that this is a little like the huge number of alternate realities of the cosmic landscape. But there is a difference which he admits. The many-worlds alternatives all have the same physical laws, while the cosmic landscape does not.
The book includes a very good discussion of the question about possible information loss in a black hole. Stephen Hawking used to argue that such an information loss actually occurs. Susskind and `t Hooft argued that information has to be conserved, and that it must somehow be stored outside the black hole, and Hawking now has conceded this point. And we also learn about black hole complimentarity, which helps explain all this by making it clear that information has no definite location in space.
I truly enjoyed this book, and I strongly recommend it.
Folks, its about physics, not theology. Given that, it is a great book. May 3, 2006
R. Kaiser (New Hampshire)
41 out of 50 found this review helpful
I a bit mystified as to why so many book reviews center around God. This is a book about physics, about using the scientific method to find out how our universe works. Indeed, it even discusses our latest tentative views about many possible universes (an infinite number of them?) might work.
This book does touch on religion at one major point. Most traditional theists, including Jews, Christians and Muslims, assume that this is the only possible universe, created by God. Modern day science - which physicists fully admit is incomplete - shows that our particular universe has a number of constants, a change of which would likely make life as we know it impossible. This has been seized upon by theists as proof of God's existence and creation of the universe. Unfortunately, this is both bad science and bad theology. I don't have time to fully explain why, but I can summarize the problem: It is a "God of the Gaps" argument, which makes God smaller and more inconsequential with every subsequent discovery.
As for the actual physics content of the book, it is great. It is not meant to focus on string theory alone (for that see "The Elegant Universe" by Brian Greene), but it does discuss string theory in some detail, with useful diagrams. Susskind also discusses cosmology, branes, M-theory and other related ideas.
Why is there Something rather than Nothing? January 29, 2007
E. MUSTECAPLIOGLU (istanbul, Turkey)
6 out of 7 found this review helpful
Very illuminative book in understanding the present state of the relevant physics and cosmology.
Really, we have no need of intelligent design theory if progress in science goes on.
Although the book is full of analogies and slogans instead of formulas, it provides a good overview of physics and cosmology.
The book is written in a lively way and thought provoking with challenging concepts.
Cosmology Explained November 10, 2006
Kenneth King (Half Moon Bay, CA)
9 out of 12 found this review helpful
I am a lay reader with an enduring interest in particle physics and cosmology, so have read many accounts of the history of physics and quantum mechanics and more recent developments in string theory and cosmology. Susskind's book is among the better works of this genre for two particular reasons.
The first is related to the way he exposits the material, which holds to a less descriptive but more analytical style. By this I mean that he walks the reader through thoughts and experiments by placing the reader in the context of the idea or discovery and has the reader think along with him as he uncovers or reveals what comes next. This makes the book engaging, and yet, more challenging, because it's easier to absorb descriptive detail, even complex description, then to have to think through each sentence and paragraph. Susskind's style is unusually clear, yet The Cosmic Landscape is a somewhat difficult, yet ultimately satisfying, read because he takes his reader seriously, and the reader finds that the author delivers the goods.
The second reason I commend this work is that Susskind considerately employs many simple diagrams, some of which are modified Feynman diagrams, but others of which are unique to his book, and which helped me envision concepts I've always had trouble with before, like the difficulty in imagining why multiple universes don't collide. These alone are worth the price of the book in my estimation.
As good as it gets! August 27, 2007
Librum (CA, USA)
5 out of 7 found this review helpful
TCL is popular science writing of the first order: a fascinating, informative, and highly entertaining tour of what rate as some of the most abstruse theories ever conceived. In Susskind's own words (p. 348):
"My main purpose in wiriting this book is not primarily to convince the reader of my own point of view; scientific arguments are best fought on the pages of technical journals and the blackboards of seminar rooms. My purpose is to explain the struggle of ideas that is about to take front-and-center place in the mainstream of science so that ordinary readers can follow the ideas as they unfold and experience the drama and excitement that I feel."
I can heap no greater praise on Susskind than to say that TCL brilliantly achieves his purpose. It is one of the finest pieces of popular science writing that I have ever read. Somewhere in this book Susskind alludes to another book he hopes to write one day. Here's very much hoping he directs that (and other) future efforts to a non-specialist readership. It is very much to the benefit of science and the public when scientists translate their work for the edification of non-scientists. Kudos to Susskind for joining the ranks of the most able popularizers!
Showing reviews 1-5 of 46
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