Rating: 
Summary: good writing, dubious math
Review: "God's Equation" has great value as an engrossing and fairly lucid account of the complex and relatively inaccessible issues that make up current cosmology; Mr Aczel should be congratulated.On the other hand ... halfway along Aczel claims Euclid didn't use the Fifth Postulate in the first book of "The Elements". Euclid proved the Pythagorean Theorem and many other, simpler concepts in Book One, which simply don't hold in non-Euclidean geometry: five minutes of research on Aczel's part would have set him straight. Aczel even claims in the same paragraph that Euclid described the properties of triangles and parallelograms (!) in the first book. Five seconds of thought would have set him straight. He claims the Fifth Postulate isn't really necessary for these things (in Euclidean geometry); if he can show that it isn't, he should publish his thoughts on the subject: authors 200 years from now would be writing about *him*. It is silly to be offended by an author's factual or logical errors, especially if they don't directly impact his main argument, but I was a little hurt. And if the author can make such basic mistakes in geometry, how can I trust what he says in wider areas like cosmology? This book is clearly geared for neophytes; how can they trust anything at all? Overall, I still enjoyed "God's Equation" and learned a lot (I think). I do wish I felt Aczel had researched it or thought it through better. Perhaps there will be improved editions in the future.
Rating: 
Summary: Good Explanation of a Mind Boggling Theory
Review: A meandering book that undertakes to explain the one recently observed fact that the universe appears to be expanding with increasing speed, with the historical fact that one of the results of Einstein's cosmology formulas predicted this expansion of the Universe. Einstein thought he was mistaken and corrected the formulas. The author does an admirable job keeping the subject interesting . The reader is exposed to the history of the experiments to prove Einstein's theory along with a large amount of anecdotal and biographical material of the main characters involved. No math is really discussed in this book, just the conclusions of mathematical formulas. I think the author included a little too much extraneous background. The reader should be prepared for an onslaught of material that makes one wonder if the author is begging for material to fill the pages.That point aside, I consider this author still one of the best at explaining science to the layman. On a par with Isaac Assimov in that respect.
Rating: 
Summary: An infinite, accelerating, and homogeneous universe
Review: A positive cosmological force contributes to the density of the vacuum. Einstein theory describes the universe as infinite in span, homogenous, and isotropic; any point in space can be a center of mass; closer universes recede slower and the further universes recede faster; and space is teeming with energy. Hubble observed that star speed was proportional to the distance suggesting space expands like a raising cake.
The cosmological constant in the field theory is the repulsive force countering the attractive force of gravity.
Alan Gluth's inflationary universe theory describes the cosmos as flat, big, and uniform. The critical mass of the universe is the density to cause collapse. Gluth derived the critical mass of the Universe when it was young, 300,000 years, too 15 decimals. Gluth believed the Universe was flat The Universe radiation was homogeneous. The horizontal problem question raise the following scenerio, if two people look at a star 13 billion light years apart and they are moving close to the speed of light; it is very probable that the light from one star will reach the other star because of an accumulate distance of 26 billion light years. So how can the radiation be homogeneous? Gluth theorized that stars are accelerating into an infinite space and the gravitational repulse must be causing it.
What is causing this acceleration? Funny energy acts on the fabric of space-time making it expand faster. Omega is the ratio of the actual density of the space-time fabric and the critical density. If the ratio k is zero, the space-time fabric is flat; if k is positive the universe is a spherical geometry; and if k is negative the space-time is hyperboloid.
Einsteins equation Ruv - I/2guv R = -8 pi G Tuv is transformed into (R'/R)^2 + k/R^2 = (8 pi G/3) * p. Here is what the symbols mean: 1) p is the density of the universe 2) R is the scale factor that measures the universe 3) R' is the rate of change of the Universe 4) g is the geometry of the universe. The geometry of the universe is hyperbolic according to general equations given by Gauss, Bolyai, and Lobachevsky. 5) G is the Newton gravitational constant 6) Tuv is the energy, momentum, and matter component. There are 4x4=16-(4 redundant)= 10 components that describe the tensor space-time geometry. The space-time geometry looks the same everywhere and is hyperboloid in space. The cosmological constant accounts for the expansion countering gravity and accelerates towards infinity.
Neta Bahcall, the density mass in the universe is 20 percent of the mass to effect slowdown.
Saul Perlmutter, in 1985 took 20 images of Super Novas and discovered 7 billion years ago the expansion slowed down but as growth occurred the distance increased as so did the speed.
Author Eddington proved Einstein theory that sunlight would bend 1.75 arcs as it pasted near the Sun's mass.
Rating:
Summary: A good read...
Review: Aczel, whose book about Fermat's last theorem was an enjoyable romp through the history of mathematics, now turns his attention to Einstein's theory of general relativity and its implications for cosmology. Based on his work with some historians who are taking a fresh look at Einstein's life and work through recently discovered notebooks and correspondence (Renn, Stachel, et.al), Aczel is able to reveal some previously unknown factoids about the 20th century's greatest scientist. For example, a previously unknown notebook from about 1912 reveals that Einstein had produced his field equation for gravitation nearly 3 years earlier than its final publication in 1915. Apparently Einstein was not convinced of the accuracy of this equation, for he abandoned it, only to rederive it 3 years later with apparently no recollection that he'd been there before. Aczel also spends some effort refuting the popular myth that Einstein was no good at mathematics. He was a superb mathematician, says Aczel, and largely self-taught, which speaks to his agile intellect and intuitive sense for fruitful areas of research. Unlike any other biographies of Einstein or expositions of relativity that I've read, Aczel takes a "mathematician's eye view" of general relativity, and spends considerable time tracing the development of the geometry of curved space through Gauss, Reimann, and several other lessor known contributors. He also reveals, which I had not known previously, that Einstein kept up an ongoing correspondence with the legendary British mathematician David Hilbert, and that Hilbert published some work of his own based on early copies of Einstein's field equations. This incident has apparently been fodder for considerable historiagraphical debate, and was only recently settled that there was no plagarism or other funny business occurring on the part of either man. God's Equation is not all Einstein, however. Aczel also introduces us to many of the nagging questions in modern cosmology, and astronomers' attempts to reconcile the recently discovered accelerating expansion of the universe with current theories. Astronomer Saul Perlmutter is central to the story's recent developments, whose supernova observing program lent considerable weight to the accelerating expansion scenario. Taking center stage for this discussion is the resurrection of the cosmological constant, Einstein's famous "blunder," which Aczel argues, has never really left cosmology. As modern astronomers have looked further and further into the universe and back in time, the cosmological constant seems more and more necessary to some theorists, as a repulsive force to counteract the attractive force of gravity (which is itself a brute simplification, since anybody familiar with general relativity knows that gravity is not a force at all, but rather a result of curved spacetime). Overall, I do recommend this book, though I'm frustrated that Aczel didn't do much more with this opportunity. This book could have easily been twice as long. I get the sense that he was hurried to get it to print for some reason, passing over stories that begged for further clarification (more, for instance, on the eclipse expeditions so central to providing proof for general relativity, and less on the roots of World War I, which delayed the expeditions). All in all, it's an excellent addition to the existing material on Einstein's life and work, and a teaser for more detail on what's really going on in modern cosmology (in the last two or three years, particularly). It makes me hunger for some publications based on Renn and Stachel's work on Einstein. I found a few typographical errors (in a discussion about the effect of Minkowski's lectures on Einstein while at the ETH, he gives a date for Minkowski's birth four years after Einstein published his paper on special relativity).
Rating:
Summary: Relatively speaking . . .
Review: For fans of "Connections-style" history of science, this is a great read. It does an especially good job of chronicling the interplay between math and physics, and how general relativity could not be developed until the appropriate mathematical constructs were available. Using the cosmological constant as the common thread in exploring how general relativity has shaped our understanding of the evolution of the universe lets Aczel pull everything together in a most satisfying way. There are some weak points, however. Sprinkling a few equations in the text does nothing to clarify his explanations and gives a simplistic view of the real mathematics involved, and his inclusion of irrelevant biographical details of minor players is a bit exasperating. Nonetheless, most readers will find this time well spent.
Rating:
Summary: God's Equation is an Enjoyable Read
Review: I find it interesting that most of the criticism of this book centers around the use of "God" in the title, or the lack of mathematical rigor associated with Aczel, etc. To me this completely misses the point. Aczel has written a book detailing the effort to produce one of the most profound advances in science and understanding, and he has done this admirably. Aczel starts with the unanswerable paradoxes vexing the greatest physicists at the end of the 19th ca, leading to the atmosphere which allowed Einstein to question the then-unalterable laws of Newton. Aczel gives insight to the great mind of Einstein and the genius that allowed him to work through the complexities of his theories. Likewise, Aczel gives insight into the great minds that preceded Einstein, and on whose work Einstein is indebted. All this is done in a clearly written and easily understandable prose. Finally, Aczel's overview of general relativity is very understandable for the layperson, who is of course the intended audience. To expect more is unrealistic - for a more rigorous treatment, go to any university graduate physics course. Finally, "God" is meant in the philosophical sense, not any dogmatic sense. Aczel so much as says this - general relativity describes the mechanics of the universe, not the question of "why", which is reserved for the mind of God. It is a gauge of the limitation of general relativity, powerful as it is; not some obtuse endorsement for religion. In writing an intelligent, moving, and overall very enjoyable book on the genius required to develop general relativity, Aczel as succeeded in spades.
Rating:
Summary: A breath of fresh air.
Review: If you are a person of faith it becomes almost impossible to not dislike the scientist exploring origins because of their dogged secularism. Amir Aczel, in this book manages to explain to the reader an important new developent in our understanding of the universe (the fact that it has been proved to be expanding at an accelerating rate) with all it's consequences, using history, especially Einstein's work, to bring it all into perspective - and do it with respect to the possibility that God may be the prime agency behind the origin of the universe after all, as Einstein freguently reminded us. No religious tome, this is a book about science, but without an adherence to an antiseptic mindset that exterminates God as possible.
Rating:
Summary: An Accessible Introduction to Complex Physics
Review: In "God's Equation", Amir Aczel explores the recent history of cosmology and physics, interwoven with a biography of Albert Einstein. Despite the fact that he is discussing complex ideas and topics, Aczel manages to explain concepts in an easy-to-understand fashion. Perhaps the most enjoyable part of the book was the biography of Einstein infused in the chapters. Einstein was an amazing scientist and a fascinating person, and Aczel reveals his life in an interesting way. The reader also learns of the great work of a number of scientific/mathematical genuises of the past- such as Euclid, Planck, and Reimann. Their discoveries, like Einstein's are explained to the reader in a surprisingly accessible way. The most interesting conclusion of this book is that the universe is expanding, and will expand forever. This seems counterintuitive, for it implies a universe that began a finite time ago and will never re-contract. This is perhaps one of the most important discoveries of all time. Overall, "God's Equation" is a highly accessible and highly recommended book. It is a fast read, and one that won't be regretted.
Rating:
Summary: Well written food for thought
Review: In this book, Aczel proposes that Einstein's Cosmological Constant, discarded and by the genius himself considered his greatest blunder, is in fact an integral part of the equation that defines the nature of the universe, its past and its future. Some mysterious force is accelerating the expansion of the universe, pushing out on space, countering gravity and making the universe accelerate towards infinity. Aczel argues that in addition to the four known forces: gravity, electromagnetism, the weak and the strong nuclear forces, there is a fifth: the cosmological constant which is the quintessence of the universe. He spoke to many experts in the fields of mathematics, physics, astronomy and cosmology and integrated the ideas of prominent scientists like Eddington, Penrose and Grossman. The chapters deal with stuff like Euclid's Riddle, Riemann's Metric, the expansion of space, the nature of matter and the geometry of the universe but it also serves as a type of biography of Einstein and a history of the development of his theories. There are quotes from Einstein' work and the text is enlivened by portraits, photographs and illustrations. Although an engaging and thought provoking text, it is sometimes difficult to grasp all of the intricacies as there are many formulas that a non-mathematician would not understand. Nevertheless a uniquely stimulating work that concludes with a helpful bibliography and thorough index. I also recommend Marcus Chown's The Universe Next Door, Mark Ward's Universality: Beyond Chaos and Martin J. Rees' Before The Beginning: Our Universe And Others.
Rating:
Summary: Einsteins's equation and the cosmic constant.
Review: Inspired by the fact that the universe is ever expanding, Aczel wrote the history from Einstein to the present of the thoughts around Einsteins cosmic constant. The main part deals with Einsteins struggles with his main equation and the discovery of the first proof for general relativity, the bending of star light around the sun. This history part is presented in kind of zooming in at those times and people, so that one temporarely becomes part of the times of the process of verificaton and recognition of general relativity. From the statements about the cosmic constant the author then leads the reader into modern times, but this time rather zoomed out, mentioning many people an theories. It's all gripping to read, but one does not get answers about the phenomena which introduced the book, namely, how the universe could possibly accelerate it's expansion.
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