The Universe in a Nutshell [Hardcover]

Hawking addresses topics such as the quest among much of the physics community to unite Einstein's theory of relativity with quantum mechanics, which would describe the universe on scales of lightyears all the way down to the atomic level. He introduces amazing concepts such as imaginary time and the possibility of our universe consisting of up to 10 or 11 dimensions. He even addresses the possibility of time travel and alien life.

The book has wonderful illustrations which help one to grasp the profound concepts with which Hawking deals. Also, the book is written in such a manner that each chapter can basically stand on its own. If you liked A Brief History of Time, I'm sure you'll like this.

This is a really great book and if you have any interest in getting a glimpse into the most incredible, yet compelling theories of the universe this book would certainly be for you.

The author writes in the foreword that the structure of the book is like a tree, the first two chapters forming a central trunk from which the other chapters branch off. Thus, after reading two introductory chapters on the theory of relativity and "the shape of time," the reader can jump to any of later five chapters on the development of the universe, black holes, the possibility or impossibility of time travel, our future, and the future journey of discovery.

Many scientists tried to avoid addressing a question about the beginning of the universe. In chapter 3, however, Hawking states the necessity of trying to understand it on the basis of science for the following reason: If the laws of science are suspended at the beginning of the universe, they might fail also at other times.

The universe is considered to have begun in a big bang, a point where the whole universe was scrunched up into a single point of infinite density. At this point Einstein's general theory of relativity cannot be used, because when the universe is small the uncertainty principle of quantum mechanics is important. Therefore, we need a "quantum theory of gravity," a unified theory of the general theory of relativity and the quantum mechanics, and this is the main subject of the book.

Hawking's own approach to the unified theory is to combine the general theory of relativity and Richard Feynman's idea of multiple histories. Many related concepts and theories, for example, holography, duality, p-branes, M-theory and superstring theory, are explained. Only in chapter 6, the story is rather close to our life, and here the author describes also excitingly how biological and electronic life will go on developing in complexity at an ever-increasing rate.

I highly recommend this book to laypersons. They will possibly get only a feeling of understanding, not understanding itself; but the book surely opens their eyes more or less about the principles of the universe already found and those on the way to be found. Physical scientists outside Hawking's field might get some frustrations, because advanced concepts at the forefront of research are not conveyed well enough by the everyday language without the aid of the mathematical language suitable for physics.