A Briefer History of Time

In the 17 years since the publication of A Brief History of Time, Dr. Hawking's bestselling exposition of physics, new data from particle physics and observational astronomy have shed light on efforts to find a Grand Unified Theory of Everything that Hawking and Mlodinow use to enhance and update their answers to basic questions about the universe: where it's going and how it began. Discussed at length are the mysterious dark matter and dark energy-both of which can only be observed by their gravitational effects and are believed to make up 90 percent of the universe. Another area of research that has exploded in the past 20 years is string theory. Hawking and Mlodinow provide one of the most lucid discussions of this complex topic ever written for a general audience. Readers will come away with an excellent understanding of the apparent contradictions and conundrums at the forefront of contemporary physics. Recognizing that much of their audience will also be science fiction buffs, they include a chapter on the possibility of time travel. ""Don't bet on it,"" the authors advise. Throughout these discussions, the authors maintain the same wry, lively tone that made the original Brief History such a delight. They close with a discussion of where physics ends and philosophy begins, ""Why does the universe exist at all?"" They cannot provide the answer, but they do provide an immense amount of food for thought. Highly recommended.