Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions

by Lisa Randall

The universe has many secrets. It may hide additional dimensions of space other than the familier three we recognize. There might even be another universe adjacent to ours, invisible and unattainable . . . for now.

Warped Passages is a brilliantly readable and altogether exhilarating journey that tracks the arc of discovery from early twentieth-century physics to the razor's edge of modern scientific theory. One of the world's leading theoretical physicists, Lisa Randall provides astonishing scientific possibilities that, until recently, were restricted to the realm of science fiction. Unraveling the twisted threads of the most current debates on relativity, quantum mechanics, and gravity, she explores some of the most fundamental questions posed by Nature—taking us into the warped, hidden dimensions underpinning the universe we live in, demystifying the science of the myriad worlds that may exist just beyond our own.

Genres: Science, Physics, Nonfiction, Popular Science, Philosophy, Astronomy, Space

499 pages, Paperback

First published January 1, 2005

About the author

LISA RANDALL is Professor of Physics at Harvard University. She began her physics career at Stuyvesant High School in New York City. She was a finalist, and tied for first place, in the National Westinghouse Science Talent Search. She went on to Harvard where she earned the BS (1983) and PhD (1987) in physics. She was a President's Fellow at the University of California at Berkeley, a postdoctoral fellow at Lawrence Berkeley Laboratory and a junior fellow at Harvard University. She joined the MIT faculty in 1991 as an assistant professor, was promoted to associate professor in 1995 and received tenure in 1997. Between 1998 and 2001 she had a joint appointment at Princeton and MIT as a full professor. She moved to Harvard as a full professor in 2001.

She was the 1st tenured woman in physics at Princeton; the 1st tenured woman theorist in science at Harvard and at MIT. She's the most cited theoretical physicist in the world in the last five years as of last autumn — a total of about 10,000 citations. In this regard, she is most known for two papers: "A Large mass Hierarchy From a Small Extra Dimension" (2500 citations); and and "An Alternative to Compactification" (about 2500 citations). Both concern "Warped Geometry/Spacetime" and show that infinite extra dimension and weakness of gravity can be explained with an extra dimension.

Lisa Randall’s research in theoretical high energy physics is primarily related to the question of what is the physics underlying the standard model of particle physics. This has involved studies of strongly interacting theories, supersymmetry, and most recently, extra dimensions of space. In this latter work, she investigates “warped” geometries. The focus of this work has been a particular class of theories based on five-dimensional AdS space which has the remarkable property that the graviton is localized and the space need not be compactified. Related work demonstrates that this theory yields a very natural resolution to the hierarchy problem of particle physics (the large ratio of the Planck and electroweak scales) and furthermore, is compatible with unification of gauge couplings. This latter class of theories suggests interesting experimental tests. The study of further implications of this work has involved string theory, holography, and cosmology. Lisa Randall also continues to work on supersymmetry and other beyond-the-standard-model physics.

Within a year of her work on extra dimensions, it was featured on the front page of the Science Times section of The New York Times. It has also been featured in the Economist, the New Scientist, Science,Nature, The Los Angeles Times, The Dallas Daily News, a BBC Horizons television program, BBC radio, and other news sources. She has also been also been interviewed because Science Watch and the ISI Essential Science Indicators have indicated her research as some of the best cited in all of science.

http://edge.org/memberbio/lisa_randall

Reviews

[Robert · Rating 1 out of 5]

I reviewed this once before and a tecnical snafu ate it when I tried to up load it...

This book is dreadful: here are the many reasons why:

The material is disorganised. The book is ostensibly about extra spatial dimensions. The concepts are introduced in the first few chapters then don't re-appear until the last few chapters. The Standard Model is introduced twice.

The explanations are poor and sometimes wrong. The section on the Pauli Principle is riddled with errors and omissions that should embarress a good A-level chemistry student. The section on CP symmetry and CPT symmetry is so bad that I did not recognise these concepts for what they were until several chapters later. These concepts are not actually difficult to explain, even if it is hard to see why they should be true: In CP symmetry, all matter is swapped for it's antimatter equivalent and the directions left and right are reversed. When this is done, no difference can be detected between before and after the swap. This symmetry is known to work for all physical processes except those involving the weak nuclear force. In CPT symmetry, as well as swapping matter for antimatter and left for right, the direction of time is reversed. This symmetry was believed to hold for all circumstances - it could have happened five times since you started reading this review and you would never be able to tell the difference! However, very recent results have suggested that neutrinos and antinuetrinos may have different masses which would mean that CPT symmetry does not apply to them. This isn't a well established result yet, though. So, really, how hard was that to explain? Randall also offers the worst introduction to the fundamental mysteries of quantum mechanics I've ever read (and I've read quite a number).

Randall can't write: Additionally to giving bad explanations, Randall also gives us a very bad story at the beginning of each chapter. These stories have no literary merit and do not make understanding the forthcoming material any easier. They are like the dialogues from Godel, Escher, Bach by Hofstadter with all wit, literary merit and purpose removed, except they aren't dialogues, either.

Pop song wisdom: Each chapter begins with a quote from a pop song. These are not profound or witty. Many, many years ago I developed the principle, "Do not get your life wisdom from pop songs." One could also say, "Do not quote pop songs at the heads of chapters unless you want to look as if you've never read a book in your life."

Repetition: Using the same unclear explanation over and over again does not make a topic easier to understand. Since it was very difficult to understand Randall's explanations of concepts I am already familiar with repeating them isn't helpful.

Bloat: The new "physics" Randall wants to explain comes in the final two chapters of a long book which is full of digressions that are irrelevant to the main thrust. Weirdly the author includes every theoretical development of the last 20 years except the only one that has a firm experimental basis (i.e. neutrino oscillation, which I'm not going to explain here). Weirdly, this would have been useful, unlike the ones she does include, because the issue of "flavour mixing" comes up at one point. Again it took me some time to realise that this "flavour mixing" was something I knew about - neutrino oscillation!

Is there anything good about this book? Well, there's an explanation of why one theory of relativity is Special and the other is General that you won't find in many other places. Is that compensation for nearly 500p of tedious, repetitive and extremely speculative barely comprehensible explanations?

Stick to the maths, Lisa; you're good at maths.

[Lewis Weinstein · Rating 1 out of 5]

I was excited to buy this book, and looked forward to learning something useful about new science. But I thought it was horrible. The explanations are unreadable. The preface was even less comprehensible. BTW, I have an engineering degree and was the CEO of a scientific research institute for 14 years. I think I am capable of reading a lay book about science. I got nothing from this one.

[Charlene · Rating 4 out of 5]

Lisa Randall is one of my favorite scientists. Her research is amazing. I highly recommend this book as well as watching her lectures online. The lectures (some 5 hours in length) help solidify the information in this book. I can't wait to see where this research leads. I have always been excited to learn about dimensions. I hope I live long enough to see the how the work of Randall and others affects our understanding or branes and the forces attached to them.

[Koen Crolla · Rating 4 out of 5]

People make too much of condescension in science writers; I've seen several reviews now praise Randall for not being condescending or patronising, possibly because Randall herself mentions that she wrote the book because so many others struck her as being patronising or condescending and professional reviewers are usually journalists and journalists are lazy hacks.
In actual fact, any work of popular science, particularly in the field of physics, is going to be condescending in places by necessity; the state of modern physics is so far removed from the physics education the modal layperson will have received (my own high school physics education got to Newton and stopped, and because that requires basic calculus I'm told that's more than most people get) that any book written for the general public has to start pretty much from zero or risk losing its readers at least some of the time. And because people who tend to read pop sci will tend to be at least sort of familiar with at least some of the ground covered already, this means at least parts of any decent book will seem unbearably patronising to them. Unlike with high-schoolers or undergrads, you can't make very many assumptions about the background and knowledge of your target audience when you're writing for the general public.

And Randall is more patronising than most, to be honest, because she makes an earnest effort to cover more ground than I've seen anyone else attempt, and she insists on repeating herself to an absurd degree. And that's good — in fact, I'd go so far as to say that Warped Passages is the first (modern) pop physics I've read that hasn't left me feeling like the field is now just too esoteric to be viable subject matter for pop sci.

(The only thing that bothers me is her irrelevant anecdotes about rock climbing and mountain biking and things, which I'm sure is exactly the sort of thing that appeals to aforementioned professional reviewers. I'm so fucking sick of the rock star physicist image; that is condescending in an undesirable way.)

[Paul · Rating 3 out of 5]

this rating is much more a reflection on me than randall's writing.

she wrote about complex theories in quantum physics and string theory in probably the most accessible manner possible. but my brain isnt great at grasping such notions so that is on me.

Randall starts each chapter with a parable fairy story to illustrate the ideas discussed in that chapter and finishes with a bulleted synopsis of what she wrote.

all in all this is a physics book for non physicists.

[Mike · Rating 4 out of 5]

A few weeks ago I came across an interesting blurb about Ms. Randall's latest book. Since I was unfamiliar with her or any prior books (one was mentioned in the write up), I did some cursory digging and found that she had written her first book in the mid-2000s. Because I wanted to be "fair" before reading the just-published book, I felt obligated to read the earlier one. Now that was a gigantic mistake! (Not the reading, just the "obligated" part.)

"Warped Passages" is a superbly written book by a leading physicist for non-physicists. The topic is (mostly) contemporary particle physics but to add the necessary depth and perspective she covers the late 19th century development of the original "atomic" models as well as classic physics topics such as: Newton's Laws of Motion, Newton's Law of Gravitation, Electromagnetic Theory, and Maxwell's Equations. From there the book continues with the 20th century revolutions that re-wrote all of the rules: Special Relativity, General Relativity, Quantum Theory (aka Quantum Mechanics) and the Uncertainty Principle.

Along with these "basics", the discovery of the essential building blocks of the universe are covered. First the "basic" items: electrons, photons, protons, neutrons are discussed, then the "sub-particles" which were found as "atom-smashers" gained power and sensitivity: the weak gauge bosons, the quarks, the neutrino. All-in-all a fairly standard progression from the early days of particle physics right up to the present day (when the Tevatron was finally decommissioned, since the LHC is now really up & running). And of course we haven't touched on the last 30-40 years of models and theories, yet. (But the book does.)

So, why am I so positive about this book? I think that Ms. Randall has written some of the best summaries and explanations of the core elements of particle physics for the past half-century. Her coverage of the Standard Model, Symmetry, Supersymmetry, Strings, Branes and dimensionality are probably the best that I have ever read for non-physicists. Not only are the presentations clear and meaningful, but she allows readers to pass over sections that contain important information which does not directly impact the main direction of the book (which is using extra dimensions and branes). I did read all of the sections. I also read all of the 40-odd math notes, which is where she placed anything that might have derailed someone who only cared about the "gist" of the topic. Overall, I think the author and editor(s) did a great job in organizing the material for a readership of many interest levels. You can stop reading here and take away my recommendation that you read this excellent book on how the universe may work. Or, you can read the next section where I give a few more details while trying to solve a small conundrum. But, read this book no matter which you decide.

Although I have not read any other reviews, I did notice that "Warped Passages" has an overall ranking that is lower than I expected. Granted it is written for those that may be more curious than the average bear, but initially I couldn't reconcile the excellent writing with this overall "judgement". I'm still not certain, but I have a few guesses.

First, the author writes in her own "voice" rather than a dispassionate, omnipotent, narrator. She is a physicist and one whose work centers on the current material of this book. As such she describes many first-hand events and impressions; perhaps these are beyond the expectations of some readers.

Secondly, and in a similar vein, she created little "stories" to illustrate the concepts that are presented in each chapter. For the most part the stories are "standalones" (although they use a recurring cast of characters), but in some of the later chapters she deliberately refers back or explains what point or concept the story was designed to explain. Personally, I found these passages redundant, but the author & publisher may have thought that some readers would not be able to connect the dots in these little "asides". Other readers may have felt this was annoying or offensive.

Thirdly, the author writes in more topical references than another author might, or another reader might prefer. Again, for myself these were neither offensive nor irritating, but not everyone may be as amused as I was by a few little left-leaning comments.

Lastly, and I really, really hope that this isn't the reason for any of the low rankings, she details some of the historically unequal treatment of men and women in physics. In the handful of places where she writes about this we see how a specific woman's contribution to a discovery or theory may not be attributed, recognized or rewarded. Does this matter? I think it does. Many people know of "Madame Curie"; some may know of the woman whose X-ray crystallography made it possible for Watson & Crick to decide on a double-helix structure for DNA, and a few may know about Einstein's first wife and collaborator, but these are only placeholders for the many other women that have been doing "real science" throughout history. To put it in perspective, the author is a notable, practicing physicist and this is her book. I think it's perfectly reasonable that she give an example or two of women who made significant, prior contributions to the advancement of physics and were not given the same recognition as men working on the same problems. So, if the misogynists didn't like these comments, tough bunnies!

[Marilyn · Rating 3 out of 5]

If you love particle physics you'll probably love this book.

The first and last fourths of the book were really interesting and mostly about new theories in particle physics.

The middle half of the book slogs through a brief history of particle physics, string theory, and multiple dimensions.

She employs a few odd tools. Most chapters begin with an Alice in Wonderland like story that is meant to demonstrate the concept to be discussed. Some readers may find it witty and amusing but I found it distracting. It is set off in italics so readers can skip ahead. There were several helpful tools though; one is a bullet list of summary points at the end of most chapters so if you wanted to skip ahead you could review the bullets and move on. Also included is a glossary of terms that I found helpful. Since I read this on a train in twenty minute intervals, I would find myself reading a passage knowing that she had explained a term two chapters ago but couldn't remember how it was relevant to the current chapter and all I had to do was refer to the glossary. She also includes endnotes which elaborate further on certain mathematical details for those curious and more familiar with the calculus involved.

Overall, I found the book to be a good broad collection of concepts around multiple dimensions, brane theories, and warped geometry as they relate to particle physics. But I found the writing to be a bit stiff and hard to follow at times. If you're looking for a discussion of the implications or real world applications of the theories she does not go into that level of detail. She does however bring up a good point: based on the models being built, we must not have a clear definition of what a dimension is.

[Rama Rao · Rating 5 out of 5]

Is gravity weaker than other three forces? A solution to the hierarchy problem in physics

Gravity is the weakest forces of all the four forces of our universe, because, according to the author, it is concentrated in another spatial dimension of the universe, and these extra dimensions could be infinitely large. The summary of this book is as follows: We live in a three-dimensional pocket of higher dimensional space, also called branes. It is like a bead on a wire that can only move along one dimension, a brane may restrict our motion to three dimensions although other dimensions exist around it. The theory of supersymmetry also explains the hierarchy problem by postulating that every fundamental particle has a heavier partner, but the theory currently predicts particle interactions that don't occur in nature. The author predicts that if extra dimensions exist, particles could be separated to prevent unwanted interactions, and that gravity could be concentrated somewhere in an extra dimension. The force's strength becomes exponentially weaker further from the gravity brane. The model consists of a pair of universes, four-dimensional branes (three space and one time), thinly separated by a five-dimensional space called the bulk. The mathematical solutions for this setup suggested that the space between the branes is warped, and objects could grow larger or smaller (less massive or more massive) as they moved back and forth between two branes, a direct result of higher gravitational force. The fifth dimension could be so warped that the number of dimensions you see would depend on where you are in the bulk. In addition, gravity is as strong as the other forces, because it is much stronger on one brane than the other. Therefore our universe is located on a brane where only weak gravitational force is felt. This idea of the author is not new since string theorists, Arkani-Hamed, Divali and Dimopoulos (group A.D.D.) suggested that if one or two of the curled-up extra dimensions of string theory had sizes as big as a tenth of millimeter, then gravity would be similarly diluted and weakened thus explaining the hierarchy problem.

There is increasing perception among some leading physicists like Ed Witten that space and time could be illusions, or it is perhaps made of simpler yet undiscovered physical parameters. We are still long way to clearly understand the concept of space and time, but the author's theory may be a step in the direction of advancement. However, one of the major problems of this theory is that it is all talk (theoretical) but no substance (no experimental evidence). We have to wait a little longer after the LHC data is completely analyzed and understood.

The book is very well written and easy to understand; the author has explained the relevant physical concepts in a simple and lucid manner; highly recommended.

[Jim Good · Rating 4 out of 5]

Most of the book is a set up for the last couple chapters, by giving a history and accounting of the Standard Model of Quantum Mechanics and some baseline information on string theory. The last couple chapters deal with theories of extra dimensions and how they might be perceived and detected. Most extra dimensional theories have finite or small scaled that wrap back on themselves. She puts forth a theory of potentially infinite but warped extra dimensions and how those would manifest. Also much discussion of branes which can trap particles to make them appear as less dimensions than there really are.

[Cyndie Courtney · Rating 3 out of 5]

I won't begin to pretend that I completely wrapped my mind around everything in this book. It definitely peaked by curiosity and I am intrigued to learn more, but this is no "particle physics for dummies". Some fascinating concepts contained within. Definitely helped open my eyes to some of the crazier aspects of our world.

[Kerem Cankocak · Rating 5 out of 5]

Önsöz ve Teşekkürler

Küçük bir kızken matematik problemlerindeki ya da Alis Harikalar Diyarında gibi kitaplardaki bulmacalara ve zekâ oyunlarına bayılırdım. En sevdiğim işlerden biri okumak olduğu halde, bilim kitapları bana genellikle daha uzak ve daha az davetkâr gelmişti; hiçbir zaman yeterince bağlanmış ya da meydan okunmuş gibi hissetmedim. Üslupları çoğu zaman okuyucuları küçümseyen, bilim adamlarına aşırı tapınırcasına ya da sıkıcıydı. Yazarların bilimin kendisini tanıtmak ve bilim adamlarının buldukları bağlantıları kurma süreçlerinin kendisini anlatmaktan çok sonuçları gizemleştirdiklerini ya da onları bulan insanları yücelttiklerini hissederdim. Esas bilmek istediğim kısım buydu.
Bilim hakkında daha fazla şey öğrendikçe onu daha çok sevmeye başladım. Her zaman bir fizikçi olacağımı ve bu şekilde hissedeceğimi tahmin etmiyordum; gençken tanıdığım hiç kimse bilim yapmıyordu. Ama bilinmeyenle yakından ilgilenmek karşı konulamaz derecede heyecan vericiydi. Görünürde alakasız olaylar arasındaki bağları bulmayı ve problem çözmeyi ve dünyamızın şaşırtıcı özelliklerini öngörmeyi heyecan verici buluyordum. Şimdi bir fizikçi olarak bilimin gelişmeye devam eden yaşayan bir varlık olduğunu anlıyorum. Yalnızca cevaplar değil ama aynı zamanda oyunlar, bulmacalar ve katılım da onu ilgi çekici yapıyor.
Bu projeye atılmaya karar verdiğimde, kafamda bilimin sunumundan ödün vermeden benim işime duyduğum heyecanı paylaşan bir kitap canlandırdım. Kuramsal fiziğin büyüleyiciliğini konuyu yanıltıcı bir biçimde basitleştirmeden ya da onu değişmeyen, pasif bir şekilde hayranlık duyulacak tamamlanmış eserlermiş gibi sunmadan aktarabilmeyi umdum. Fizik insanların genelde fark ettiklerinden çok daha yaratıcı ve eğlencelidir. Fiziğin bu taraflarını henüz bu aydınlanmayı kendi başlarına yaşamış olmayan insanlarla paylaşmak istedim.
Karşımızda bizi baskılamakta olan yeni bir dünya anlayışı var. Ek boyutlar fizikçilerin evren hakkındaki düşünme biçimlerini değiştirdi. Ek boyutların dünyaya olan bağlantıları iyi yapılandırılmış pek çok başka fizikle ilgili fikirlere de bağlanabilecek olmasından ötürü, ek boyutlar evren hakkında daha eski, hali hazırda doğrulanmış gerçeklere yeni ve ilgi uyandırıcı geçitlerle yaklaşmanın bir yoludur.
Dâhil ettiğim fikirlerden bazıları soyut ve varsayımsaldır ama meraklısı olan herhangi biri açısından anlaşılmaz olması için hiçbir neden yoktur. Kuramsal fiziğin büyüleyiciliğinin kendi adına konuşmasına izin vermeye ve tarihi ve kişileri çok fazla vurgulamamaya karar verdim. Fizikle ilgilenen bir insanın herhangi belirli bir tipte olması gerektiği ya da bütün fizikçilerin tek tip oldukları gibi yanıltıcı bir izlenim vermek istemedim. Deneyimlerime ve konuşmalarıma dayanarak söyleyebilirim ki, zeki, ilgili ve gerçek mevzu hakkında daha çok şey isteyecek kadar açık olan birçok okuyucu olduğundan oldukça eminim.
Bu kitap en gelişmiş ve ilgi uyandırıcı kuramsal fikirler konusunda cimrilik etmiyor ama kendi kendine yeterli olması için elimden gelenin en iyisini yapmaya çalıştım. Hem uygulandıkları temel kavramsal gelişmeleri hem de fiziksel olayları dâhil ettim. Bölümler, okuyucuların kendi geçmişleri ve ilgi alanlarına göre istedikleri gibi okuyabilmelerine el verecek biçimde düzenlenmiştir. Bu sürece yardımcı olmak için, ek boyutlar hakkında daha yakın zamandaki fikirleri sunarken daha sonra değineceğim konuları listeledim. Aynı zamanda ek boyutlarla ilgili bölümlerin sonunda ek boyutlu evrenler için her bir olası seçeneğin diğerlerinden nasıl ayrıldığını açıklamak üzere de listeleme yaptım.
Ek boyutlar fikri muhtemelen çoğu okuyucu için yeni olduğundan, ilk birkaç bölümde bu sözcükleri kullandığımda neyi kastettiğimi ve neden ek boyutların var olabileceğini ancak görünmez ve elle tutulamaz olduklarını açıkladım. Sonrasında, parçacık fizikçilerinin gerçekte oldukça varsayımsal olarak kabul edilen bu araştırma alanına giren düşünce şekillerini aydınlatma işine yaklaşımlarında kullandıkları kuramsal yöntemlerin ana hatlarını çıkardım.
Ek boyutlar hakkındaki yakın zamandaki çalışmalar cevapladığı soruları ve yöntemleri güdülemek için hem daha geleneksel hem de daha modern kuramsal fizik kavramlarına dayanmaktadır. Böyle bir araştırmaya neyin güç verdiğini açıklayabilmek için yirminci yüzyıl fiziğinin kapsamlı bir incelemesini de dâhil ettim. Eğer bu incelemeye göz atmak isterseniz rahatınıza bakın. Ama eğer yaparsanız pek çok güzel şey kaçıracaksınız.
İnceleme parçacık fiziğine ve parçacık fizikçilerinin bugün kullandığı en önemli kavramlara dönmeden önce genel görelilik ve kuantum mekaniğiyle başlamaktadır. Oldukça soyut olan ve –kısmen bu kadar soyut olmalarından ötürü– genellikle ihmal edilen bazı fikirleri sundum ama bu kavramlar artık deneylerle onaylanmış olup bugün yaptığımız bütün araştırmalara girmektedirler. Her ne kadar bu materyalin hepsi ek boyutlar hakkında daha sonra göreceğiniz fikirleri anlamak için gerekli olmasa da, çoğu okuyucunun daha bütün bir tablo almaktan memnun olacağına inanıyorum.
Bunun ardından, son otuz yıldır üzerinde çalışılmış olan, daha yeni, daha kuramsal kavramları anlattım; bunlar süpersimetri ve sicim kuramı olarak adlandırılmaktadırlar. Geleneksel olarak fizik, kuram ile deney arasında karşılıklı bir etkileşim gerektirmiştir. Süpersimetri bilinen parçacık fiziği kavramlarının bir uzantısıdır ve önümüzdeki deneylerde iyi bir ihtimalle test edilecektir. Sicim kuramı farklıdır. Yalnızca kuramsal sorular ve fikirler üzerine kuruludur ve matematiksel olarak henüz tamamen formüle edilmemiştir; dolayısıyla sicim kuramının öngörülerinden henüz emin olunamamıştır. Bana gelince, ben bu konuda bir bilinemezciyim; sicim kuramının nihayetinde ne olacağını ya da kuantum mekaniğinin ve çözmek için yola koyulduğu kütleçekim kuvvetinin sorularını çözüp çözmeyeceğini bilmiyorum. Ama sicim kuramı, uzayın ek boyutları hakkındaki kendi araştırmamda faydalandığım yeni fikirlerin bazıları için zengin bir kaynak olmuştur. Bu fikirler sicim kuramından bağımsız olarak var olmaktadırlar ama sicim kuramı bize altlarında yatan bazı varsayımların doğru olabileceğini düşünmemiz için iyi bir sebep vermektedir.
Bu bağlamı kurduğumuza göre, son olarak, ek boyutlar hakkındaki çok sayıdaki heyecanlandırıcı yeni gelişmelere dönüyorum. Bu gelişmeler bize, ek boyutların büyüklüklerinin sonsuz olabilmesine rağmen görünmez olabileceklerini ya da bizim daha yüksek boyutlu bir evrendeki üç uzay boyutuna sahip bir çukurda yaşadığımız gibi kayda değer şeyler söylemektedirler. Aynı zamanda artık neden bizimkinden çok farklı özelliklere sahip olan ve görünmeyen paralel dünyaların olabileceğinin sebeplerini biliyoruz.
Metin boyunca, fizik kavramlarını denklemler olmadan açıkladım. Ama matematiksel ayrıntılar hakkında daha fazla bilgi edinmek isteyenler için bir matematiksel ek bölüm dâhil ettim. Metnin kendi içinde, bilimsel kavramları açıklamada kullanılan mecazların çeşitliliğini genişletmeye çalıştım. Herkesin kullandığı betimleyici kelime dağarcığının çoğu uzaysal benzerliklerden gelmektedir ama bunlar çoğu zaman temel parçacıkların ve ek boyutlu, resmedilmesi zor uzayların küçücük dünyalarında başarısız olmaktadır. Bana öyle geldi ki daha az geleneksel mecazlar, hatta sanat, yemek ve kişisel ilişkiler üzerine olanlar bile soyut fikirleri açıklamada en az diğerleri kadar iyi olabilirlerdi.
Her bir bölümde yeni fikirlere geçişi sağlayabilmek için, bölümlere daha tanıdık mecazlar ve sahneler kullanarak anahtar bir kavramı ayrı tutan bir kısa hikâyeyle başladım. Bu hikâyeleri yazarken eğleniyorum dolayısıyla bölümü okuduktan sonra eğer isterseniz bağlantıları yakalamak için dönebilirsiniz. Hikâyeleri bölümlerden “aşağı” doğru giden ve kitap boyunca “yatay” bir şekilde ilerleyen iki boyutlu bir anlatım olarak düşünebilirsiniz. Ya da onlara bir bölümde sindirmiş olduğunuz fikirleri tartmanıza izin veren bir çeşit eğlenceli bir ev ödevi problemiymiş gibi davranabilirsiniz.
Nice dost ve iş arkadaşı bu kitap için amaçladıklarımı yerine getirmemde bana yardımcı oldu. Çoğu zaman neyin peşinde olduğumu bilmeme rağmen, ne zaman başarılı olduğumu her zaman kestiremiyordum. Bir grup insan cömertçe ayırdıkları zaman, verdikleri cesaret ve anlattığım fikirlere duydukları heyecan ve meraktan ötürü teşekkürü hakkediyorlar.
Birkaç yetenekli arkadaşım kitabın taslağının çeşitli evrelerinde yaptıkları paha-biçilemez yorumları için özel bir teşekkürü hakkediyor. Anna Christina Buchmann, muhteşem bir yazar, anlattığım hikâyeleri tamamlamayı öğrenmeme yardımcı olan hem fizik hakkında hem de genel olarak çok güzel ve incelikli yorumlarda bulundu. Her zaman beni cesaretlendirmeyi amaçlayan paha biçilemez yazarlık ipuçları sağladı. Polly Shulman, aşırı derecede yetenekli bir başka arkadaşım, her bölümü dikkatlice okuyup yorumda bulundu. Onun mantıklı ve oyunbaz zihnine hayranım ve onun yardımını almış olduğum için çok şanslıyım. Lubos Motl, muhteşem bir fizikçi ve kendini işine adamış bilim iletişimcisi (ki onun bilim dünyasındaki kadınlar hakkındaki yanıltıcı görüşlerine kulak asmayacağız), daha okunur halde değilken her şeyi okudu ve her aşamada olağanüstü derecede işe yarayan öneriler ve cesaret verdi. Tom Lewenson yalnızca yetenekli bir bilim yazarının sağlayabileceği önemli tavsiyelerde ve birtakım son derece önemli önermelerde bulundu. Michael Gordin bir bilim tarihçisinin ve bu cins edebiyatın ustasının bakış açısını sundu. Jamie Robins kitabın taslağının birden fazla nüshası üzerine bilgi dolu yorumlarda bulundu. Esther Chiao taslak üzerine yararlı görüşler ve bilimin dışında bir geçmişi olan zeki, ilgili bir okuyucunun son derece yararlı bakış açısını verdi. Ve Cormack McCarthy’nin kitabın son kısımlarında verdiği değerli öneriler ve cesaretlendirmesinden ötürü çok memnunum.
Birtakım insan bu projenin başlangıç aşamasında bana yardımcı olan ilgi çekici hikâyeler ve gözlemler sağladı. Massimo Porrati bazılarının burada gözüktüğü fevkalade gerçekleri barındıran bir kaynaktır. Gerald Holton’ın yirminci yüzyılın başlarındaki fizik anlayışı kuantum mekaniği ve görelilik hakkındaki düşüncelerimi zenginleştirdi. Jochen Brocks bilim yazarlığında neyi sevdiği hakkında kullanışlı içgörüler verdi ve bazı yazarlık fikirlerini teşvik etti. Chris Haskett ve Andy Singleton’la olan sohbetlerim fizikçi olmayanların neleri öğrenmeyi ümit edebileceklerini anlamamda bana yardımcı oldular. Albion Lawrence bazı zor bölümleri çözümlememde bana yardımcı olan birtakım değerli katkılarda bulundu. John Swain sunuş yapmanın bir çift güzel yöntemini benimle paylaştı.
Birçok meslektaşım değerli yorumlarda ve önerilerde bulundu. Teşekkür borçlu olduğum diğer birçok insan arasından, Bob Cahn, Csaba ve Zsusanna Csaki, Paolo Creminelli, Joshua Erlich, Ami Katz ve Neil Weiner hepsi kitabın önemli kısımlarını okudu ve bilgili yorumlarda bulundu. Aynı zamanda Allan Adams, Nima ArkaniHamed, Martin Gremm, Jonathan Flynn, Melissa Granklin, David Kaplan, Andreas Karch, Joe Lykken, Peter Lu, Ann Nelson, Amanda Peet, Riccardo Rattazzi, Dan Shrag, Lee Smolin ve Darien Wood hepsi kullanışlı yorumlarda bulundu ve tavsiyeler verdi. Howard Georgi bana ve yukarıda adı geçen birçok fizikçiye bu kitapta benimsenen etkin kuram anlayışı hakkında tavsiyeler verdi. Aynı zamanda yararlı eleştiriler, öneriler ve cesaretlendirmeler sağlayan Peter Bohacek, Wendy Chun, Enrique Rodriguez, Paul Graham, Victoria Gray, Paul Moorhouse, Curt McMullen, Liam Murphy, Jeff Mrugan, Sesha Pretap, Dana Randall, Enrique Rodriguez ve Judith Surkis’e teşekkür ederim. Aynı zamanda Marjorie Caron, Tony Caron, Barry Ezarsky, Josh Feldman, Marsha Rosenberg ve diğer aile üyelerine okuyucu kitlemi daha iyi anlamamda yardımcı oldukları için teşekkür ederim.
Greg Elliot ve Jonathan Flynn bu kitapta bulunan harika fotoğrafları çektiler ve önemli katılımları için olağanüstü derecede minnettarım. Rob Meyer ve Larua Van Wyk’e kitap boyunca yapılan birçok alıntı için izin almamda yardımcı oldukları için teşekkür ederim. Kaynakları doğru düzgün bir şekilde belirtmek için her türlü çabayı gösterdim. Eğer doğru bir şekilde belirtildiğinizi hissetmiyorsanız lütfen beni bilgilendirin. Aynı zamanda bu kitapta anlattığım araştırmamda birlikte çalıştığım iş arkadaşlarıma, özellikle Raman Sundrum ve Andreas Karch’a teşekkür ederim, her ikisiyle de çalışmak harikaydı. Ayrıca tartışmaya yerim kalmadıklarım da dâhil olmak üzere bu konu ve alakalı fikirler hakkında düşünmüş bütün fizikçilerin katkılarını belirtmek isterim. Aynı zamanda Ecco Press editörüm, Dan Halpern’a, Penguin editörlerim, Stefan McGrath ve Will Goodlad’e ve ABD’deki ve İngiltere’deki kopya editörlerim, Lyman Lyons ve John Woodruff’a bu kitap için olan destekleri ve çok sayıda yardımcı önerilerinden ötürü onlara olan saygımı belirtmek isterim. Ve edebi danışmanım, John Brockman’a ve aynı şekilde Katinka Matson’a önemli yorumlamaları ve tavsiyeleri ve bu kitabın yayımlanmasındaki paha biçilmez yardımları için teşekkür etmek isterim. Aynı zamanda Harvard Üniversitesine ve Radcliffe İleri Araştırma Enstitüsüne bu kitaba odaklanmam için zaman sağladıkları için ve MIT, Princeton, Harvard, Ulusal Bilim Vakfı, Enerji Departmanı ve Alfred P. Sloan Vakfına araştırmamı destekledikleri için müteşekkirim. Son olarak, aileme: ebeveynlerim, Richard Randall ve Gladys Randall’a ve kardeşlerim, Barbara Randall ve Dana Randall’a bilimsel kariyerimi destekledikleri ve mizahlarını, düşüncelerini esirgemedikleri ve yıllar boyunca olan cesaretlendirmeleri için teşekkür etmek isterim. Lynn Festa, Beth Lyman, Gene Lyman ve Jen Sacks son derece destekleyiciydiler ve hepsine yol boyunca olan muhteşem tavsiyeleri ve önerileri için teşekkür ederim. Ve en son olarak Stuart Hall’a içgörülü bakış açısı, yardımcı yorumları ve bencil olmayan desteği için çok minnettarım.
Hepinize teşekkür ederim ve umarım katkılarınızın geri ödendiğini düşünürsünüz.


Lisa Randall
Cambridge, MA
Nisan 2005

[Richard Seltzer · Rating 4 out of 5]

On the plus side, this book will expand your understanding of the concept of "dimension". It also has clear explanations of developments in physics in the days of Einstein and the early stages quantum theory. Above all it gives you a sense of physics as a living, growing, very human endeavor -- a constant challenge, a source of one fascinating puzzle after another, requiring creativity and ingenuity to simply imagine all that might be possible. Half the book deals with theories that have not yet been proved -- fascinating ideas that might turn out to reflect the "real world" but that regardless of that have a puzzle and artistic appeal.

The author is not a reporter or science popularizer, but rather one of the leading theorists. If what she presents is an accurate account of recent developments (and I have no reason to doubt that it is), she deserves a Nobel Prize.

Unfortunately, while she seems to try hard to make her book readable and to make the concepts accessible to the non-professional, the narrative becomes increasingly difficult to follow. A typical passage from the second half of the book: "This meant, paradoxically, that you could use perturbation theory to study the original strongly interacting, ten-dimensional superstring theory. You would not use perturbation theory in the strongly interacting string theory itself, but in a superficailly entirely different theory: weakly itneracting, eleven-dimensional supergravity. This remarkable result, which Paul Townsend of Cambridge University had perviously also observed, meant that despite their different packaging, at low engergies, ten-dimensional superstring theory and eleven-dimensional supergravity were in fact the same theory. Or, as physicists would say, they were dual." What?????

It's like trying to read a book in a language you don't know. Somehow I managed to look at all the words, but I don't feel that I really "read" the book. And I could probably look at all those words several more times without understanding any more of it. So I come away impressed at the author's knowledge and accomplishments and creative enthusiasm, but totally frustrated. I simply have no idea what she is talking about. If only I could find a book that unravels the mysteries of this book...

[Ollie · Rating 1 out of 5]

I really had my hopes up for Warped Passages after reading Brian Greene’s Hidden Reality. Not because I enjoyed that book so much, but because it so thoroughly confused and frustrated me that I just assumed another book would do a better job of explaining the wonderful world of hidden dimensions.

Unfortunately, Lisa Randall’s Warped Passages is no better. Just like Hidden Reality, Warped Passages starts out well enough by explaining some basics about quantum physics but then very quickly snowballs into a mess of jargon and gobbledygook. And Randall tries, she really does, by making the subject a little bit more lighthearted, peppering her chapters with stories, examples, an idiotic non-fiction story involving Athena and Ike (who cares?), and trying show off her music taste by quoting “relatable” lyrics at the beginning of each chapter (she has terrible taste in music, guys), but it all just ends up being frustrating. It just seems ridiculous to use the media of 2-D words on paper (with the occasional drawing) to explain something as complex. An episode of PBS’s NOVA or even comic strips (like Ph.D. Comics) do a better job with much less effort.

Warped Passages might be more easy to understand if someone were using this book as a way to study the subject (and reading the chapters over and over again) or if we could actually see the math (instead of just asking us to imagine certain ideas or to trust Randall on a concept over and over and over again), but for the general audience, this is just a very frustrating book. I could not wait for it to end.

At the end when Randall is talking about her contributions to the field, she says “It took a while before physicists understood and believed us.” Well then, what chance do the rest of us have?

[Karl Nehring · Rating 4 out of 5]

Through the early pages of the book, Dr. Randall's writing style drove me nearly crazy, but as I continued to read, either she started to get her bearings or else I got more used to it. In any event, I found this a fascinating book. Technically it is very challenging -- I am not going to pretend that I truly grasped most of what she was writing about; however, I was able, at least at some level, to follow the story she was telling, and that was a welcome sort of challenge. I enjoyed this book enough to have recently ordered "Knocking on Heaven's Door," her newest tome.

[Brandy Cross · Rating 3 out of 5]

Warped Passageways is a bit of an oddity. On the one hand it’s comprised of fairly in-depth science, on the other hand it’s poorly written and the work could have greatly benefited from simply removing many of her explanations. In addition, the book additionally suffers from the inclusion of very poor attempts at analogous storytelling at the front of every chapter, where a fictional setting is loosely linked to the premise being explained in the chapter, and sometimes very sloppily giving the reader the wrong impression.

At the same time, it’s an incredibly accessible introduction to a lot of concepts in current theoretical physics, with relatively dumbed down explanations for basic and not-so-basic concepts. If you can follow Randall’s fairly iffy explanations, it’s a great primer from an insider perspective. I personally found some of the fallacies in the examples to be annoying beyond the point of redemption (e.g., use a shower curtain with water droplets sliding down it as an example of a possible 1-axis dimension). If you skip those or figure out how to ignore them, the book becomes much better.

Overall, this is cute.

[John Micallef · Rating 1 out of 5]

This was by some margin the worst science book i have ever read. My 2 main issues with the book are the myriad analogies and the reverence for string theory.

Given the high level topic of this book, i assumed the text would not be 'dumbed down' as if the audience was high school students with only a semester of physics. But my assumption was wrong. This book is written such that chapters are prefixed by an analogous fiction and each paragraph after is riddled with allusion and metaphor to a ridiculous degree. The author will often belabor a point through this exposition followed by a slew of metaphors regardless of how complicated the original point even was leading this book on a fairly interesting and niche topic to become incredibly and increasingly boring.

I am unsure why so many physicists in the early 2000's held string theory in such high regard. It was a cool idea that just straight up does not describe the space we live in, by definition. It's like someone talking about "The Force" from Star Wars with the same respect as Einstein's field equations. It just feels weird, and wrong.

[Tyler · Rating 2 out of 5]

Boring

[Charles · Rating 4 out of 5]

The Standard Model of particle physics is the most successful scientific theory ever produced. It's capable of making predictions that turn out to be incredibly accurate, down to many decimal places. It's produced surprising predictions that turn out to be true. The discovery of the Higgs boson a few years ago cemented in the capstone of its success. But it also has a massive, gaping hole in the middle of it, a flaw that has consumed the efforts of several generations of physicists and continues to represent an impenetrable mystery. Where is gravity? Why is gravity?

This book is ten years old now, but still presents an absorbing account of the efforts being made to unravel this mystery in a readable and approachable manner and is an excellent starting point for anyone looking to find out about string theory, supersymmetry and extra dimensions. This is a cluster of theories that can interact in surprising ways, but Randall manages to plot a course through the thicket that makes a degree of sense. As with all popular science books it's hobbled by the requirement to translate purely mathematical concepts into semi-intuitive ideas. This will always present problems, as an intuitive understanding is inherently flawed--if you really want to grasp the nature of these theories you need to do the maths (I'd recommend Leonard Susskind's The Theoretical Minimum: What You Need to Know to Start Doing Physics and its companion on Quantum Mechanics).

There are a few problems with the book that might have been improved. As others have noted, she opens with several chapters concerning higher dimensions and how they could fit into what appears to be a strictly three dimensional world, but then veers off into presenting relativity, uncertainty and the Standard Model, only returning to the subject of dimensionality 10 chapters later. Unfortunately there's no way of discussing these subjects properly without shoehorning in all the undergraduate spadework that needs to be covered for anything else to make sense. The book would probably have flowed a bit more elegantly if the introduction to dimensionality were moved later in the work. But since the book is fundamentally about the physics of extra dimensions I can understand the motivation to dive in from the start.

Written in 2005, this book presents an excellent overview of the previous couple of decades of work into Physics Beyond the Standard Model. What it really needs is a second edition, perhaps in a couple of years when we have results from the LHC at 13TeV. In many places through the book she talks about the predictions being made and looks forward to the LHC results. It's no secret that many of these predictions have fallen flat. Some variants, like Minimal Supersymmetry, are already dead in the water, with no evidence of the relatively light superpartners they predict. Most of the others are looking very troubled. Where do we go from here? It's not enough to carp from the sidelines, like Smolin, and complain that these theories are all bunk. We need answers and a way to plug up the yawning void sitting at the heart of the Standard Model.

The road that science takes is littered with the husks of thousands of dead theories--once-promising ideas that had to be cast aside for better alternatives. There's no doubt that many of the theories presented in Randall's book will join their number. But if ideas are a vector we need to know where it's starting from, and Prof. Randall presents an excellent overview of the state of play in PBSM in the early years of this century.

[David]

As is the case with most books on more or less contemporary theoretical physics, this one gives me the impression that I understand it … until I turn a page. Then, all too yearling, the moonbeams saturate field mice with gas masks and did you ever blibbit? Rikkul fiorg, either! Soon enough, die Korridore de mon esprit становиться カオスTaka 土地 of cose welke 似乎是正确的 but may merely bele des faux friends. I wish I had made a count of the number of times “IF” is used in this book. While reading, I found my old Senior High Physics text (1974). Might have been a different subject. I didn’t understand that one either! Worth the effort for the mental pushups, but I would never claim to have understood it :-)

[Gofita · Rating 4 out of 5]

I know I won't be able to truly understand quantum mechanics and particle physics until I sit down and learn the math somehow...but I thought Lisa Randall did an amazing job trying. I caught glimpses of our invisible world of virtual particles, gluons, squarks, 5th dimensions and branes.

My world has been rocked. Nuff said.

[Luz · Rating 3 out of 5]

Sort of hard to follow, and confusing. However, I read it as a highschool AP chemistry student and it very well explained quantum mechanics and various other physics theories in a sort of simplistic way.

Unsure if I'd recommend but I would definitely reread it to see if my understanding changes.

[B. Factor · Rating 1 out of 5]

Chock full of misleading analogies, painful allegories, and irrelevant material cut-and-pasted from other failed writing projects.

[Tom Schulte · Rating 4 out of 5]

Lisa Randall is my new hero. A bright, intelligent woman dominating a field mostly populated with men and taking time out to popularize the esoteric musings of theoretical physics for the rest of us.

[Illiterate · Rating 3 out of 5]

Randall focuses on the hierarchy problem and the speculative theories that try to solve it, including string theory, branes, extra dimensions.

[Jason Turner · Rating 4 out of 5]

This is one of the most intellectually demanding books I have ever taken on, yet Lisa Randall demonstrates these concepts in “easy-to-follow” explanations. While I occasionally found myself online for clarification, particularly with challenging ideas like branes, bulks, and bosons, the book progressed with simple clarity thanks to the use of analogies. From Newton’s laws to particle physics’ hierarchy problem, unraveling the fundamental principles that shape our understanding of the universe’s fabric is laid out for the foundation to her final arguments on hidden dimensions. Reading this work has been a humbling and an enriching experience. I’m proud to have undertaken this intellectual challenge and have a deep appreciation for this new knowledge.

Randall’s argument made short: Our universe is a 3D Brane (Brane, like membrane, is a lower dimensional object, much like a sheet of 2D paper floating in the middle of a room) and the higher dimensions may be both large and small around us, the Bulk (the room which holds the floating 2D paper is the Bulk of higher dimensional space). So, by tackling the Hierarchy Problem, involving Higgs Boson and Planks Mass, Randall uses dimensions as explanations to why gravity’s strength is weaker in comparison to other non gravitational forces of our universe, like nuclear strong, nuclear weak, and electromagnetism. Dimensions can be warped around us without us even realizing it. I hope that explanation is understandable 😂 if not read the book!

[Raúl · Rating 3 out of 5]

Obra realmente dura. Para ensayos de divulgación que planteen las dimensiones extras y ls avances en teoría de cuerdas etc es más recomendable y asequible "El universo elegante" de Brian Greene

[David · Rating 4 out of 5]

Best description of alternate physics dimensions.

[Steven H · Rating 5 out of 5]

A FRANK DISCUSSION OF STRING THEORY, EXTRA DIMENSIONS, AND MORE

Lisa Randall is an American theoretical physicist who is Professor of Science in the physics faculty of Harvard University.

She wrote in the Preface of this 2005 book, “When I decided to embark on this project, I envisioned a book that shares the excitement I feel about my work without compromising the presentation of the science. I hoped to convey the fascination of theoretical physics without simplifying the subject deceptively or presenting it as a collection of unchanging, finished monuments to be passively admired… extra dimensions are a way to approach older, already-verified facts about the universe via new and intriguing pathways… I’ve described some newer, more speculative notions that have been studied for the last thirty years---namely supersymmetry and string theory. Traditionally, physical has involved an interplay between theory and experiment. Supersymmetry… has a good chance of being tested in forthcoming experiments. String theory is different. It is based solely on theoretical questions and ideas and isn’t even completely mathematically formulated yet, so we can’t be certain of its predictions. As for me, I’m agnostic on this subject---I don’t know … whether it will solve the questions of quantum mechanics and gravity it sets out to address. But string theory has been a rich resource for new ideas, some of which I’ve exploited in my own research on extra dimensions of space.”

In the Introduction, she explains, “Do I believe in extra dimensions? I confess I do. In the past, I’ve mostly viewed speculations about physics beyond what’s been measured---including my own ideas---with fascination, but also with some degree of skepticism. I like to think this keeps me interested, but honest. Sometimes, however, an idea seems like it must contain a germ of truth.” (Pg. 3)

She acknowledges, “Admittedly, the evidence for extra dimensions will be somewhat indirect, and we will have to piece together various clues. But that is true of almost all recent physics discoveries… Let me say at the outset that obviously not all new ideas prove correct, and that many physicists are skeptical about any new theories. The theories I present here are no exception. But speculation is the only way to make progress in our understanding. Even if it turns out that the details don’t all align with reality, a new theoretical idea can still illuminate physical principles at work in the true theory of the cosmos. I’m fairly certain that the ideas about extra dimensions we’ll encounter in this book contain more than a germ of truth.” (Pg. 9)

She observes, “There is nothing wrong with ignoring an extra dimension that’s too small to be seen. Not only the visual effects, but also the physical effects of tiny, undetectable processes can usually be ignored. Scientists often average over or ignore (often unwittingly) physical processes that occur on immeasurably small scales when formulating their theories or setting up their calculations.” (Pg. 28) She continues, “Everyone, including physicists, is happy to return to a three-dimensional universe when higher-dimensional details are beyond our resolution… we will… describe a higher-dimensional universe in lower-dimensional terms when the extra dimensions are miniscule and higher-dimensional details are too tiny to matter.” (Pg. 30)

She admits, “String theorists often suggest… that curled-up dimensions are as small as the Planck length… Planck-length-size compact dimensions would be extraordinarily well-hidden; there is almost certainly no way for us to detect something so small. Therefore, Planck-length extra dimensions would very likely leave no visible trace of their existence. So even if we live in a universe with Planck-length extra dimensions, we would still register only the three familiar dimensions. The universe could have many such tiny dimensions, but we might never have the resolving power to find out.” (Pg. 42)

She explains, “finding the connection between string theory and the real world is a daunting task. The problem is that string theory is defined at an energy scale that is about ten million billion times larger than those we can experimentally explore with our current instruments… An enormous theoretical gulf separates string theory, as it is currently understood, from predictions that describe our world. String theory’s equations describe objects that are so incredibly tiny and possess such extraordinarily high energy that any detectors we could imagine making … would ever be likely to see them… it is not even always clear how to organize string theory’s ingredients and determine which mathematical problem to solve… Without some speculative assumptions, string theory looks like it contains more particles, more forces, and more dimensions than we see in our world… We don’t yet know … even how to find a single manifestation of string theory that conforms to our world. We would have to be very lucky to extract all the correct physical principles that will make the predictions of string theory match what we see.” (Pg. 69)

She notes, “Supersymmetry [is] a strange new symmetry transformation that interchanges bosons and fermions… However, supersymmetry as a symmetry of nature is still hypothetical, since no one has yet discovered supersymmetry in the world around us. Nonetheless, physicists have two major reasons to think that it might exist in our world:… Superstring theory, which incorporates supersymmetry, is the only known version of string theory that has the potential to reproduce the particles of the Standard model. String theory without supersymmetry doesn’t look as if it could possibly describe our universe. The second reason is that supersymmetric theories have the potential to solve the hierarchy problem… Before extra-dimensional theories were introduced as potential alternatives, supersymmetry was the lone candidate solution. Because no one yet knows whether or not supersymmetry exists in the external world, all we can do at this point is evaluate candidate theories and their consequences.” (Pg. 258) Later, she adds, “This leaves us with the outstanding question: does supersymmetry exist in nature? Well, the jury is still out. Without more facts, any answer is mere conjecture.” (Pg. 270)

She recounts, “String theory looked like it could potentially describe all known forces. It was a promising candidate theory of the world.” (Pg. 288) She continues, “Even though the additional structure of string theory was a nuisance, the superstring had succeeded where other potentially more economical theories had failed.” (Pg. 291) She goes on, “In many physics departments… the superstring revolution was more like a coup… Even without any observations that supported string theory, many physicists decided that string theory’s potential for reconciling quantum mechanics and gravity was reason enough to support its claim to prominence.” (Pg. 293)

She states, “If a string is so small that its length is undetectable, the string might as well be a particle; no experiment could tell the difference… The string’s one-dimensional extent is just as invisible to us as the tiny curled-up extra dimensions we considered earlier… such a string is much too small to see.” (Pg. 294)

She also acknowledges, “It is as if string theory is a beautifully designed suit that doesn’t quite fit… some physicists simply define string theory as whatever resolves the paradox of quantum mechanics and general relativity at small distances… It is still too early to decide the ultimate merits of a string theory description of the world… Nonetheless, string theory is s remarkable theory. It has already led to important insights into gravity, dimensions, and quantum field theory and it’s the best candidate we know of for a consistent theory of quantum theory gravity… But string theorists have yet to make good on the promises they made in the 1980s to connect string theory to the world.” (Pg. 301) Later, she adds, “M-theory has the potential to give a more unified, coherent picture of the superstring and to fully realize string theory’s potential as a theory of quantum gravity… [But] No one yet knows the best way to formulate M-theory. But string theorists now think of it as their primary goal.” (Pg. 316-317)

She concludes, “Which, if any, of these ideas describes the real world? We’ll have to wait for the real world to tell us. The fantastic thing is that it probably will… some of the extra-dimensional models I’ve described have experimental consequences… And from these consequences, we might be able to deduce the existence of extra dimensions. If we do, our vision of the universe will be irrevocably altered… We certainly don’t yet know all the answers. But the universe is about to be pried open… Secrets of the cosmos will begin to unravel. I, for one, can’t wait.” (Pg. 456, 458)

This book will be of keen interest to those looking for clear (and frank) explanations of contemporary physics.

[Chris Lynch · Rating 5 out of 5]

"Every now and then a man's mind is stretched by a new idea or sensation, and never shrinks back to its former dimensions." (O.W. Holmes, Sr. 1858)

Holmes would, I think, have agreed that this book is a provider of such mind-stretching ideas. Here you'll find an excellent discussion of some of the more radical new ideas from the model-building camp of theoretical physics. Taking ideas of higher dimensions and branes borrowed from string theory, Prof. Randall and co-researchers have produced interesting models of physics in which the extra dimensions of string theory are shown to not all necessarily be miniscule curled-up planck-scale regions beyond experimental probing. She demonstrates possibilities for larger additional dimensions the existence of which might be experimentally verified when the Large Hadron Collider swings into action, and alternative possibilities to supersymmetry for unification of the forces of nature.

Don't be fooled by the journo's reassuring commentary on the cover. No journalist wants to admit that they can't make head nor tail of a 'pop' science book. Though Randall steers clear of mathematics there are many abstract concepts in this book that are not at all easy to grasp, especially the idea of non-spatial symmetries and symmetry breaking. 'Remarkably clear' is a very relative term here - in that, given the inherent difficulty in explaining these subjects to the uninitiated, yes, she's done a great job; but that doesn't mean it's easy-going or accessible.

There's not very much cosmology in this book. It mainly concentrates on spatial geometry, particle physics, quantum field theory and the (possible) relationships between them. Of course the obligatory explanations of relativity, quantum mechanics and the standard model of fundamental particles and forces, all de rigueur for any pop science tract, comprise the first half of the book.

Prof. Randall has actually made a very brave move in publishing this work, because her conjectures might be disproved or at least thrown into doubt by the results of LHC experiments (whereas string theory as a general concept will neither be proved nor disproved because the LHC doesn't probe anywhere near the energy scales needed to do so). More power to her elbow for doing so.

[Doug Trani · Rating 4 out of 5]

For people who are not familiar with the subject matter, this is a great introduction to particle physics and string theory. Lisa Randall is brilliant and she has a way of making extremely abstract concepts comprehensible to those of us with no formal training in either field. However, the book was written before the Large Hardon Collider was completed in 2008. Dr. Randall proposes a number of fascinating hypotheses that may or may not have been substantiated by experiments conducted at this facility over the past 15 years. I hope she will someday write a sequel to update us on the evolution of her thoughts based on the empirical evidence acquired since the time this book was published.