The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics (Hardcover)

by Leonard Susskind (Author)
Key Phrases: string theory, quantum field theory, holographic principle, Quantum Mechanics, Black Hole War, Stephen Hawking (more...)

Editorial Reviews

From The Washington Post
From The Washington Post's Book World/washingtonpost.com Reviewed by James Trefil What is it about black holes, anyway? To most scientists, a black hole is something like a duck-billed platypus in the sky: weird, unusual, esoteric and not all that connected to real life. On the other hand, people just can't seem to get enough of them. Any teacher will tell you that it's a whole lot easier to get a class interested in black holes than in DNA, even though the latter will most assuredly have a real impact on their future and the former will not. Oh well, if you must learn about black holes, you could do a lot worse than to pick up this engagingly written book. Stanford physicist Leonard Susskind provides a marvelous introduction to the subject that is both readable and easy to understand. Or at least as easy as something involving the two great 20th-century advances in science -- relativity and quantum mechanics -- can possibly be. You see, until the end of the 19th century, scientists who thought about the fundamental structure of the universe had concentrated on normal-sized objects moving at normal speeds (think billiard balls). We associate this kind of science with Isaac Newton. Then, in rapid succession, the 20th century brought two revolutions. The first, which dealt with objects moving near the speed of light or having very large mass, was relativity, the brainchild of Albert Einstein. The second revolution came when people starting thinking about very small objects, such as the stuff inside the atom. The resulting theory is called quantum mechanics and was developed by a small group of young scientists in the 1920s, the most familiar probably being Werner Heisenberg of uncertainty-principle fame. One note in passing: These revolutions didn't so much replace Newton as extend his reach. Like a tree, mature sciences grow by adding new material while leaving their heartwood intact. With increasing urgency over the past 50 years, theoretical physicists have tried to tie these two great 20th-century advances together, to produce what Nobel Laureate Steven Weinberg calls "The Final Theory." So far, we have not been successful. But if you can't bring the two fields together, you would at least like to know that they don't contradict each other, that they are mutually consistent. And this is where Susskind's "war to make the world safe for quantum mechanics" comes in, because for a period of almost 20 years, it looked as if there could well be a fundamental contradiction between the basic postulates underlying the two theories. At least that's what Stephen Hawking argued, and when Hawking talks, physicists listen. Remember that a black hole is an object so compact and so massive that nothing, not even light, can escape from it. It is, in fact, a kind of one-way gate in the universe: Stuff can fall in, but nothing can come out. Because it involves both a large mass and extremely high energy, the black hole forms a kind of nexus where both relativity and quantum mechanics come into play. Thus, if there are going to be problems joining these two fields, they are likely to turn up in the behavior of black holes. In 1983, Hawking proved that, against all expectations, black holes are not eternal. In fact, over unimaginably long spans of time, they evaporate, more or less like a puddle of water on a sunny day. And that's when the "war" started, because if a black hole evaporates (and everyone agrees that it will), what happens to all the information that was carried by the stuff that fell in? That information might include things like the mass of the particles that fell in, their spin, their identity and all kinds of other properties. Hawking argued that this information was lost forever, that the black hole was truly a one-way street to oblivion. The problem is that one of the basic laws of quantum mechanics is that information cannot be lost. (I should point out that in quantum mechanics the term "information" has a technical meaning, and that losing it is more of a problem than, say, losing the shopping list you need at the supermarket.) In the case of the evaporating puddle, for example, it is theoretically possible to reconstruct the puddle by looking at the air molecules above the spot where it used to be. Hawking argued, however, that with the material that evaporated from the black hole, no such thing is possible, that the information simply disappeared. Susskind's account of his reaction to this claim and of driving home from the conference where it was first presented, distractedly scribbling equations in the frost on his windshield, beautifully describes how disturbing the idea of disappearing information was to those of us steeped in the lore of the quantum. In the end, Susskind and his colleagues were able to resolve this dilemma and, in the words of the subtitle, "make the world safe for quantum mechanics." I won't spoil the book for you by telegraphing the ending. Suffice it to say that it involves a tour through the whole arcane menagerie of modern physics -- quarks, gluons, branes, strings. And this illustrates the main problem faced by authors of this sort of book. Black hole astrophysics is about as far from everyday experience as you can get, which means that the author has to spend a lot of time bringing the reader up to speed (indeed, it takes Susskind almost 200 pages). Even when, as in this book, there is virtually no mathematics, there is an overwhelming number of strange new concepts. Consequently, I recommend digesting this book in small segments, allowing each new concept to settle in before moving on. In the end, The Black Hole Wars is as good an introduction as you're going to find to the strange world of black hole astrophysics. Add that to the chance to ride along as real scientists resolve a fundamental issue and you have the makings of a great read.
Copyright 2008, The Washington Post. All Rights Reserved.

From Bookmarks Magazine
Cosmology has been sexy since Carl Sagan, Richard Feynman, and Stephen Hawking stormed onto the scene three decades ago, popularizing science for the masses. In The Black Hole War, Susskind plays on our insatiable appetite for the gee-whiz moment, combining lucid explanations for some complex ideas with stories that tend to confirm the eccentricities of the highly intelligent. In fact, it’s the author’s knack for teaching and his conversational prose that make the book accessible and therefore appealing to a wide audience. And, of course, it’s never a bad idea to drop Hawking’s name in a book’s title. “Susskind explains this dizzying notion about as clearly as is probably possible,” George Johnson writes of the author’s theory—even if, in the end, we need “a lot more data” (New York Times Book Review).
Copyright 2008 Bookmarks Publishing LLC

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Product Details

• Hardcover: 480 pages
• Publisher: Little, Brown and Company (July 7, 2008)
• Language: English
• ISBN-10: 0316016403
• ISBN-13: 978-0316016407
• Product Dimensions: 9.3 x 6 x 1.6 inches
• Shipping Weight: 1.5 pounds (View shipping rates and policies)
• Average Customer Review: 4.4 out of 5 stars See all reviews (31 customer reviews)
• Amazon.com Sales Rank: #63,246 in Books (See Bestsellers in Books)

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Customer Reviews

Most Helpful Customer Reviews

79 of 80 people found the following review helpful:

5.0 out of 5 stars A popularisation that mostly works, July 22, 2008

By	Nigel Seel (Andover, UK) - See all my reviews (REAL NAME)

Susskind describes the decades-long battle between the quantum mechanics community and the general relativists as to whether information is lost when objects pass through the event horizon of a black hole and the hole eventually evaporates. According to Prof. Hawking and the GR community, as nothing can ever reappear from inside an event horizon, the information is indeed totally lost.

Susskind and Gerard 't Hooft begged to differ. Loss of information would violate the basic time-reversibility of QM: Hawking's ideas would lead to universe-destroying phenomena (p. 23). Somehow, the information locked the wrong side of the event horizon must leak out via Hawking radiation. But how?

The resolution of this dilemma took many years of conjectures and refutations. Susskind takes us on a tour of entropy, holographic principles and physics at the Planck scale. And the adversarial plot keeps the reader turning the pages.

I am normally very dubious about popularisations. They proceed by raking up endless analogies which never quite fit together, so that by the end of the book, your mind is like that jig-saw puzzle you bought and could never fit together.

This book was never going to be the exception - the mathematics of quantum field theory, general relativity and string theory are just too arcane for popular culture concepts to cohere around. However, there are wonderful insights all the way through this book and we do end up learning something about the large scale map of the territory. Apparently even the experts find it hard to get the whole thing into one focus.

29 of 36 people found the following review helpful:

5.0 out of 5 stars Susskind shines !!, July 16, 2008

By	Wojciech Langer (Toronto, Ontario) - See all my reviews (REAL NAME)

This is absolutely the greatest example of what popular science book about theoretical physics/cosmology should be !! Writing is so brilliant, witty, straightforward, direct and succinct, that regardless of education level, anybody can enjoy interesting content (history of science as well as author's personal story) of "The Black Hole War". Author uses analogies in the best possible way, comparable only to Brian Greene and Michio Kaku. Drawings are frequent, well selected, informative and easy to understand. He writes: "The real tools for understanding the quantum universe are abstract mathematics: infinite dimensional Hilbert spaces, projection operators, unitary matrices and a lot of other advanced principles that take a few years to learn. But let's see how we do in just a few pages". AND HE DELIVERES !! While this book could be a starter for anybody, I recommend it to all who know Kip Thorne's famous work. For reason unknown to me, important black hole "war" is not mentioned in "Black Holes & Time Warps" at all, therefore Susskind's work becomes great extension to BH history of science. Professor Susskind created a true masterpiece where he even acknowledges coexistence of science and faith by writing: "The British intellectual world seems to be big enough for both Dawkins and Polkinghorne". Nothing but big applaud for the author and his effort !!

24 of 30 people found the following review helpful:

4.0 out of 5 stars Black Holes, November 16, 2008

By	Sanford Aranoff (NJ) - See all my reviews (REAL NAME)

The book discusses a problem. According to Hawking, when an object falls down a black hole (BH), all information is lost. The problem is that this violates a principle of physics that information is never lost. The future cannot lose track of the past, for then the past would cease to exist, as the only meaning to the past is present observations and records. Susskind proposes a solution that took him a decade to resolve, and he discusses this in the book. The solution is the Holographic Principle, which is that all the information inside the 3-dimensional sphere of the BH resides on the 2-dimensional surface. An object falling down a BH never crosses the surface, and so the information is not lost. There is a "dual description" that does not refer to the inside.

Susskind makes heavy use of String Theory to establish the theory. Actually, one can arrive at the same conclusion without the use of String Theory or quantum mechanics, by simply focusing on basic principles of physics and general relativity (GR). According to GR, it takes an object forever to reach the BH, and so it never gets inside. We therefore cannot speak about the inside. Everything falling down a BH is eternally falling, and so the information is not lost. We cannot speak about the inside of the BH. This then is exactly Susskind's Holographic Principle, where all information is outside the BH.

Science, and in particular physics, is a collection of theories. A theory is a mathematical system along with observational and experimental agreement. If it is impossible in principle to perform an observation, the theory cannot speak about that situation. Science also includes guesses, research proposals, and hypotheses, not all of which are theories.

The confusion arises from the formal existence of a solution of GR that from the viewpoint of the falling object, the object crosses the event horizon in finite time. However, since it is impossible in principle to observe an object "entering" the BH, this formal solution does not exist in reality.

If we accept the argument that something that a falling observer (someone who cannot return nor communicate with the rest of the world) can observe is considered as a valid scientific observation, we then lose our ability to criticize people for believing that the dead go to Heaven. The dead person (one who cannot return nor communicate with the rest of the world) observes Heaven. We scientists must be very careful about our scientific reasoning, and not give others the opportunity to twist it to make it sound as if we support religion, as is, unfortunately, often the case.

In summary, the principle of objective observation implies that no object can enter a BH.

Another point is that the formal solution of GR from the viewpoint of the falling observer is not a valid solution of GR. This is due to the proven existence of a singularity at the center. Since the object reaches the singularity in finite time, this solution is not valid. If we insist on accepting this formal solution, we get into paradoxes, as is usually the case when one accepts formal invalid solutions.

According to the Holographic Principle, no future theory can discuss the inside of a BH.

I gave four stars. The book makes excellent reading. It helps clarify some aspects of String Theory. For this, I give it three stars. His points about information residing outside the BH give it another star. I do not give it five stars, as his main point about where the information is can be proven by understanding and applying basic principles of science. We scientists and teachers must never lose sight of basic principles.

Susskind makes the common error of defining a BH as a place where light cannot escape, implying that the idea of an inside of a BH is a meaningful concept, contradicting his own Holographic Principle. A correct definition of a BH is a mass so large that objects falling towards it are time-dilated and red-shifted out of existence.

Another error in the book is mentioning "the 3-dimensional space inside the BH". The geometry is very much non-Euclidean. Approaching a BH is geometrically similar to moving eternally outwards to the "end" of the universe. Speaking about the inside of a BH is geometrically similar to speaking about space outside the universe, i.e., not meaningful.