Customer Reviews

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

5 star:		(34)
4 star:		(21)
3 star:		(7)
2 star:		(1)
1 star:		(2)

 

 

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.

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.

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 !!

The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics is really several books in one. On the surface, this book tells the human story behind a debate that divided the physics community for decades: what happens to the information in the matter that is absorbed by a black hole, and can that information be retrieved or is it lost forever?

Yet in attempting to explain the various interconnections between general relativity, quantum field theory and string theory, Susskind has also provided us with a second book: a great general physics primer. Thirdly, by effectively telling the history behind some science's greatest discoveries, Susskind has penned a very nice book for those interested in the history of science. Finally Susskind has made all three of those books more accessible and enjoyable by infusing his off-color personality.

This book covers a lot of ground, and at times it seems to lose a sense of flow as it delves into many different areas of physics, at each stop providing a primer of the basics. Yet by Chapter 5 the book really starts to heat up. Even though it is only five pages, they are five really good pages. This is where Susskind best makes the connection, calling a black hole horizon "the most concentrated form of information that the laws of nature allow." As he guides us through the potential implications of information loss, he simplifies many complicated subjects without watering them down. We have wonderful treatments of the holographic and equivalence principles, entropy and the laws of thermodynamics. We also are treated to great historical accounts of the many conferences and papers that put faces and personalities behind the unraveling of the debate surrounding information loss and black holes.

There are times when he seems to use footnotes to his own peril, such as his explanation of how to calculate entropy versus bits of information in Chapter 7. At first he indicates that they are calculated in the same way, but in his footnote he clarifies that they differ by a mathematical factor. I would have appreciated it more had he made his points accurately in the text instead of having to explain them in poorly structured footnotes.

At least one other aspect of this book might, unfortunately, alienate some from what is an excellent read. Susskind is unapologetically irreverent regarding religion. In Chapter 17, while recounting his frustration with the information-loss debate, he discusses time he spent at Trinity College in Cambridge and how it gave him "Cathedralitis." He outlines his disdain for the idea of intelligent design. There is also an inexplicably long section on Mormon history that seems totally irrelevant. These sections added little. His efforts to breathe life and personality into an abstract subject do give readers a sense of his personality. I simply think he should have steered clear of controversial topics.

The only other warning I can give people regarding this book is to set aside sufficient time in order to truly digest it. While, in theory, one could read this book in a week, to think through and understand all the examples takes some time. This book took me a long time to digest, and the books I have waiting to be read have multiplied during that time.

CONCLUSION

Initially I suppose I was somewhat put-off by the self-serving aspect of Susskind writing a book that starts off sounding like "I am right and Hawking is wrong." You have to read between the lines for it, but it's unclear if Hawking saw Susskind as a key player in the original debate about black hole information loss. I personally suspect that what was a "war" to Susskind was less than that to Hawking. In the end, some think this debate may not be over.

Where Susskind succeeds is in making an interesting story out of the debate. That makes readers want to understand some complex areas of physics, even if only from a 20,000 foot view. The way Susskind covers string theory and how it relates to other disciplines is particularly well done. For that alone, this book is worth the price of admission.

This is a great book that is well worth your time. I plan to seek out Susskind's other books soon.

Enjoy.

I find the material covered by Leonard Susskind in The Black Hole War intrinsically interesting, and Mr. Susskind does a creditable job of laying it out. The problem with this book is not the subject matter, but rather the writing and, even more so, the editing. The editor should have reigned in Mr. Susskind's penchant for rambling, tangential explanations. Covering this material without mathematics is a daunting task, and Mr. Susskind gives it a reasonable shot. But I was often left with the feeling that I should have had a better understanding than I did. For instance, his treatment of "horizon atoms" left me scratching my head.

One other aspect bothered me, and that was the overly blunt assessment of Stephen Hawking's current cognitive abilities. It was speculative and not particularly nice. A scientist search for truth needs to be bounded by a respect for the personal (as opposed to professional) privacy of living fellow scientists.

Finally, the whole premise of a "war" is really labored. Scientific theories change over time as new facts arrive. War is something else. The Catholic Church went to war against Galileo. Mr. Susskind participated in a, at-best, spirited debate.

If you are a fan of Black Hole theory, you have to read this book. There is enough intrigue here to keep you turning the pages, and the physics primer on Black Holes, Quantum Mechanics and Relativity is very approachable.

This is not an in-depth book on the physics of Black Holes - on the contrary, this is an enjoyable read for those who appreciate the topic and respect the brilliance of Leonard Susskind. This book tells the story that few of us have heard (from any side) - and shows us the human side of theoretical physics.

I have had the pleasure of attending lectures at Stanford with Prof. Susskind for the past 4 yrs. now. While his wit and colorful commentary do come out in the book, you will only get a glimpse of why he has such a following amongst "quantum groupies" and academics alike.

I highly recommend this book.

Excellent reading for those interested in the latest developments (~2008) in theoretical gravitational, high-energy, and string physics, straight from one of the field's most distinguished and original practitioners. Most valuable are his anecdotes from being on the front lines of this scientific debate, particularly his interactions with Hawking and 't Hooft. There are also many imaginative and graphic explanations of black hole physics, for example the "dumb hole" (or "acoustic black hole") analogy and the "Alice's airplane" description of de-localization near an event horizon. Though the black hole war may be over, others rage on. Perhaps Susskind will treat us to an account of some of those in the future...

If you want a clear explanation of the basics of quantum mechanics and string theory, read this book. In addition to learning more than you ever thought possible about the physics of black holes, author Leonard Susskind provides clear definitions of the seemingly craziest new developments in theoretical physics, such as The Holographic Principle, Black Hole Complimentarity, and anti-de Sitter Space.

If you're interested in theoretical physics, you can't go wrong with this book.

This book explains well and understandably, why Prof. Hawking's view on black holes could not be entirely correct. Up to that point, I feel an interested layman who has had some exposure to physics (like me...)can follow the argument.
The way his argument leads to string theory still is intuitively comprehensible, or so I felt.
After that, it became obscure to me; however I do not think, this is Prof. Susskind's fault, but the subject matter simply becomes too counter - intuitive for all but the full-time-experts in this field.

This is certainly one of the better "popular science book" reporting on the edges of physics! ( e.g. the two books by Michio Kaku seem more like science fiction to me).

This book tells the story of the "battle" between the author and Stephen Hawking regarding the latter claim that information is irretrievably lost in black holes.
This story is the extraordinary account of the paradigm shift that has occurred in physics in the last 25 years. Moreover, the book reads like a novel thanks to the various analogies and the anecdotes concerning the lives and personalities of the physicists involved. In summary, a very recommendable book for someone who wants to keep abreast of the advances in quantum gravity and cosmology, although the author discusses also the basic concepts of quantum mechanics and relativity.
Very strange things seem to happen in the vicinity of black holes and, as Susskind says, this needs rewiring of our brains, as we had to do before for relativity and quantum mechanics. When someone approaches and finally crosses a black hole horizon we have a similar situation as the famous Schrödinger's cat paradox. For the astronaut crossing the horizon, nothing happens (if the black hole is big enough so that he does not still notice the effect of the tidal forces). For the observer outside he deducts that the astronaut is fried to death. Believe it or not, this is not a contradiction in physics because the two of them will never be able to compare notes. Susskind calls this paradox black hole complementarity. The holographic principle and Maldacena's duality (well explained in an article in Scientific American not too long ago) are also part of the resolution of the battle for which Hawking finally conceded defeat in 2007.
Chapter 23 hints to a new duality that could indirectly provide experimental evidence for String Theory. Strings and hadrons behave in similar ways and the Relativistic Heavy Ion Collider in Brookhaven is investigating the properties of the quark-gluon plasma which mirror, 20 orders of magnitude higher, the properties of fundamental strings. Quantum gravity in Anti de Sitter space would be similar to quantum chromodynamics. However, our universe is not an Anti de Sitter spacetime. In any case some light between the shadows is finally shining in quantum gravity.