Customer Reviews

Relativity Demystified

5 star:		(2)
4 star:		(3)
3 star:		(2)
2 star:		(3)
1 star:		(3)

 

 

The five stars are for the CLARITY and EXPLICITNESS of this book, for what the author intends and accomplishes, as opposed to a comparison with other GR books that have different goals.

If you are self-studying GR, this is the book to have, even if you own others. If you are taking a GR course and don't find GR trivially easy or straightforward then this book will HELP.

While this may not be the very best GR book it is certainly the best for those readers lacking the math skills (or who have forgotten the math) to jump into a 'graduate level textbook.'

[I am also reading "Gravitation" by Misner, Thorne, and Wheeler, along with several other GR books, and "Relativity Demystied" is helping to make that 1300+ page book and others much more readable.]

This book takes the reader step by step through the tensor analysis required to build up the Einstein Field Equations.

Numerous examples are worked in explicit detail, and (doable) excerizes are offered with most chapters. Exercise answers are provided in an appendix.

If you want to go beyond popular accounts of Relativity but don't have the math background for a 'graduate level textbook' then thi s is almost certainly the answer.

This book is also MUCH less expensive than almost every other useful GR textbook so it is tremendous value, even as a supplement to more advanced texts.

Does it make GR easy? No. Does it make GR POSSIBLE to understand? Absolutely.

As Einstein himself reportedly said, "As simple as possible, and no simpler."

This book covered a lot of the practical topics in GR. The writing is quite easy to understand. In some places, it seems to be too short. For example, the explanation of the basis in coordinate basis is not very clear. [Just refer to Carroll] However, be careful if you are the first time study in GR. You should get one of the other standard books, like Schutz, Weinberg, MTW(Misner, Thorne, Wheeler) otherwise, you will not be able to move too far in this area. Also, I really hope the editor/author can do a bit more thorough job in proof reading before releasing the book. There are many places where you could find sign errors or the indices placement are not correct. For example, the definition of Christoffel Sympbol in terms of metric and also the definition of symmetrization and also the -ve sign in the proper time definition....If you already know about the subject matter, this is not a bad reference book, just a bit tiring in keeping track of these minor errors.

While this is not exactly the "learning of relativity at the speed of light" the book advertises, unlike many others of the Demystified series, this volume does indeed have its high points.

The lead up to Einstein's Field Equations -- although the notational gymnastics and some of the mathematics was daunting -- is nevertheless first class. It gives the reader a very much-needed window into the role the Linear Algebra notion of mathematical mappings and transformations -- especially as viewed from the point of view of "basis vectors," through "one forms," and on to "partial derivatives of Tensor Calculus" -- play in bootstrapping one's way up from the local Newtonian/Euclidian frame of reference to the more generalized space-time Reimann/Malinowsky frame. And most importantly, it shows by carefully selected examples and exercises how tensor calculus takes over from Linear Algebra in moving from the more local Newtonian/Euclidian frame to the more generalized space-time frame.

In fact, reading between the lines of the book, one could argue that the whole of understanding the mechanics of relativity is grasping fully this single concept: of how to move mathematically from reference frame to reference frame -- that is, from inertial frames moving relative to one another in the Euclidian world to doing the same in the Space-time world.

Doing this is not easy either conceptually or mathematically but is a necessity for getting from Newtonian to Einsteinian physics. If the reader learns to appreciate that the heavy-duty mathematics is required only for this task, and only in this light, then the ride will be infinitely easier.

Even in Taylor and Wheeler's very down to earth treatment of relativity (in their "Spacetime Physics"), this kind of understanding is left in the background for the reader to infer and to ferret out on his own. A great deal of time is save in the earlier chapters of this volume by forcing the reader to understand early on why working ones way gradually up the ladder to the tensor Calculus is necessary: so that he is better able do all of the mathematical heavy-lifting seamlessly, later.

One word of caution to the reader, which also is my only serious criticism of the book: The written dialogue is painfully sparse, so every word must be read carefully, weighed and parsed for its full meaning. It is helpful to read the book three times: First as an overview to see where the author is headed; and then a second time to understand the mathematical content -- especially the dizzy array of notations -- and then finally to put all the pieces together. That is, read it a third time just to confirm that one understands fully how the larger concepts match up with the corresponding mathematics.

It seems much easier for the authors of physics and mathematical texts to roll out reams of equations than to give just the minimal explanations about how these equations relate to the underlying concepts they are supposed to explain and describe. Why leave such important connections to the reader?

Realizing that this is not a book of prose, still it would be helpful sometimes to give ample and clearly written explanations, with even (god forbid), a little repetition from time to time, just as a guide so that the reader can confirm that he is making the correct interpretations along the way.

Anyway, I am hooked on the Demystified Series and hope this book will be great preparation for the upcoming Demystified volume on String Theory.

Four Stars

"Learn Relativity at the Speed of Light" is found on the back cover of this book and I think it's true. It was aproximately 1.23 light years ago when I first purchased this book and I am now on page 208(out of 328 total). My point is that the book is very good but to get through it requires a lot of work; relative to the math and physics background that you possess. I was totally stumped on pages 2 and 3 (Maxwells current-magnetic field equation). It will help to supplement this study with a book on tensor calculus and another relativity book by Hartle or Schutz. The worked examples and chapter quizes were great though and worth the effort.

I've purchased a whole book shelf of the Demystified series, though I've only just started using them. As a former physics undergrad, these books at least *appear* to offer a level of treatment that I can handle as I wade back into the subject. The one I've been using the most is Differential Equations Demystified, and I've found that very helpful so far.

*This* book, however -- General Relativity Demystified -- proved somewhat of a disappointment. Basically, before you can get into the physics, you have to get some handle on the mathematics of Tensors, which is covered in the early chapters, but I simply found the treatment opaque. I'm planning to get some other books on Tensors and study them carefully. Then I plan to return to this book, and see if the later parts of the book -- which deal with the physics -- prove to be accessible, once I have the tensor math down.

Possibly, if the author rewrote the early part of the book to clarify the tensor discussion, he might still have a hit here. As I say, though, other books in the series look pretty good, and I'm very happy with the DfEQ Demystified book, which I've really been working my way through and learning something in the process.

A Great introduction to Relativity. One caveat: Read the introduction to find out the necessary math requirements. To get the most out of this text multi-variable calculus (Calc 3 at least) and at least an introduction to Linear Algebra is necessary. I would also suggest reading the first three chapters of Schumann's Tensor Calculus.

I love that he uses matrices for the metric tensor. This makes understanding other tensor operations easier such as how one forms and the line element correspond.

His many examples of tensor calculus are invaluable. How to generate Christoffel (affine connections) symbols for absolute differentiation are clearly stated. He probably should have spent more time on exterior derivatives since this is the modern tie in to relativity and non-commutative differential geometry.

The section on the Riemann and Ricci tensors is great. The examples are complete in how to compute these beasts. It also has a good section on Cartan structures that could use a more modern algebraic treatment.

I loved the chapter on the Einstein Tensor. This was the first text that allowed me to finally understand why the cosmological constant was added by Einstein, later removed and it's resurgence in modern relativity.

The coverage of the Energy Momentum tensor is well fleshed out. I particularly liked the section on dust clouds. I was able to create a computer model of dust clouds from his example metric in the book.

The chapter on black holes was great and allowed me for the first time to understand the Kerr metric and actually use it for calculating black hole curvatures.

I think the author needs to spend more time on proof reading. Through most of David's series I notice many small errors in the examples that keep me scratching my head for hours trying to figure out what I have done wrong in my calculations.

The above is a small nitpick with a very good book and all of David's book series.

As most will tell you, there is no single GR book that someone can read and come away feeling that GR is understood. This was indeed my experience. I started using Weinberg in an advanced undergrad class and then used Meisner et al. in graduate school. Sure, I solved loads of problems, but I still felt like I didn't get it. I then read "Tensors, Differential Forms..." by Lovelock & Rund and felt better about the math but I needed to understand the fundamental physics better. I then read Wald and made a little more progress, but needed to put it all together. This is where Demystified comes in to sew together an understanding of both the nitty gritty and big picture. (I then later found the freely available notes by Sean Carroll, who incidentally was a class ahead of me at my undergrad. His notes, and likely the book based on these notes, are great for tying together the math and physics in a way a physicist thinks - perhaps the best of the lot.)
Anyway, Demystified has it strengths and weaknesses:

STRENGTHS
* Detailed Solutions: sometimes you just need to see someone trudge through calculations and their tricks to get the feel for the calculations. After all, physicists spend most of their time calculating things.
* Intuitive Feel: in several areas, the author provides an intuitive feel for what some elements represent, e.g. the Stress-Energy tensor.

WEAKNESSES
* Typographical Errors: the book is littered with them, in the text and equations. These could leave a novice reader scratching his head.
* Physics Errors: the most glaring on p.163. See Marion "Classical Dynamics" p. 326 for the correct solution.
* Vacillating Notation: for example, sometimes the covariant derivative is an upside-down delta, sometimes it's a comma. There are many infractions of this.
* Gravitational Waves: the book falls apart in this final section.

Use this book if you already have a good understanding of advanced physics and mathematics and some exposure to GR.I don't think it would be helpful to many others.

With only a background in microelectronic engineering,I found that this book helps me a lot in understanding the maths related with GR. It has illuminating examples and step by step explanation on the mathematical details is what makes this book outstanding.Thanks for writing such a great book to help me survive through my course in GR!

As a holder two degrees in Physics(BS and MS)a word of caution to any layperson who is tempted to buy this book, thinking it will offer a royal road to easily understanding Einstein's Relativity;it won't. Some books are written to teach; this book was written to impress others - in my opinion.

I concur with the last reviewer, there are just too many mistakes. Not only index manipulation errors, but just outright wrongheadedness. The example of passing from the Christoffel Symbols of the first to the second kind by "simply rasing an index" is just plain wrong. It's the LAST only, obvious if he had used better and more transparent representations, like [ij,k] or similar. Did the positive reviewers even work through any of the computations to check? "Mathematics is not a spectator sport."

The author chooses an infelicious mix of excessive almost compulsive detail in certain basic computations (chain rule manipulations especially), and then none at all when the going gets tough and the real fun begins. Statements like reparametrizing curves to send a certain partial derivative to zero when deriving the equation for the geodesic is just thrown out there. On such occasions a novice could be excused for thinking she is being hookwinked.

On a somewhat positive note, the treatment of basis vectors and 1-forms as partial derivatve operators and differentials almost succeeds, but I'd recommend the rigor of Carrol if you really must understand. The early presentation of coordinate transformation matrices is clearer than some. The worked basic examples with polar coordinate manipulations, usually left as exercises, are useful to a newcomer.

The book is, clearly, designed for a physicist, one who actually calculates stuff, and not a mathematician.

Even at this price, though, I would avoid it. I found its style tiresome and often erratic. I didn't finish it, and especially I have no idea what other mistakes might have been lurking in the later pages.