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The Elegant Universe
Background
Greetings, all. This book is yet another departure from my standard software theme, but a fascinating one nonetheless. Ever since the discovery of relativity and quantum mechanics, the everyday world and the world as described by science have diverged. We have no frame of reference for time running at a different rate, nor for particles jumping through solid objects. Yet it is these very discoveries which have driven physics (and technology) for the past fifty years. Even worse, scientists have been unable to reconcile these difficult-to- understand theories with one another. Today, though, there are solutions in sight. String theory promises to revolutionize science once again by uniting the theory of the big (relativity) with the theory of the small (quantum mechanics), and now that they understand these theories better, scientists can explain to the rest of us how our world truly works. Michio Kaku did an excellent job with his Hyperspace five years ago, and now Brian Greene gives us a different and updated perspective. Although this book is not written for everyone, it is directed at anyone with a decent science background (high school physics), and a desire to learn more about how our reality works.
The Scenario
As the saying goes, let's start at the beginning. Science has recently (where recently = 100 years, recent in historical terms) faced down three major conflicts in its world view. The first, the conflict of Newton's theory of motion versus Maxwell's law of electromagnetism over whether a light wave can be outrun, was resolved by special relativity (Newton lost). The second conflict, and one initiated by the discovery of special relativity, was whether gravity can be transmitted instantaneously across distances. (Special relativity, of course, states that nothing can be transmitted instantaneously). From this conflict was born general relativity, the theory of curved space, and Newton lost again (although, to be fair to Newton, he was correct as much as he could have been). The third conflict, caused by the implications of general relativity (anyone see a pattern?), was and is between general relativity and quantum mechanics. Simply put, the theory that describes the big and the theory that describes the small do not make sense together. Therefore, either one is correct, or the atoms that make you up behave differently than the planet upon which you stand. The answer to this conflict may very well be string theory.
After a quick introduction to these conflicts, and the place of string theory in the modern framework of physics, Greene takes us on a looping yet fascinating tour through special and general relativity, quantum mechanics, and the details of the conflict between them. This foundation for his description of string theory is quite helpful in bringing the book down to the level that most people can understand (especially liberal arts grads :-). In the process, Greene shows how the weirdness and unpredictability of quantum mechanics is simply unreconcilable with relativity, given our current formulation of both theories.
Of course, such a state cannot continue forever. Enter string theory. String theory basically states that the universe is fundamentally made up of oscillating loops of "string", and it is those oscillations which determine the nature and makeup of the universe. String theory also postulates that the universe is composed of several rolled-up dimensions, influencing the vibrations of the strings, and thus the makeup of our universe.
Without going into detail (that's the author's job), string theory has gathered a lot of evidence and momentum in the past years, and what I have sketched is only a 5-minute sound bite. There's plenty more detail of both the theory and its implications in the later sections. Greene closes by explaining where physics and string theory are headed, and pronounces his hope that soon we will be able to hold in our hands a fundamental explanation of the universe (the Theory of Everything [TOE], the Holy Grail of physics).
What's Bad?
Not too much. I found some of the later chapters to drag somewhat, delving into mathematics that I neither wanted nor needed. The chapter on black holes, especially, held great promise, but tended to drag at times, on a subject that I consider horribly fascinating.
What's Good?In a sentence, this book makes modern physics accessible. I dare say any Slashdot reader could readily read and enjoy the material, with only a little stretching here and there. It is important that we as a people know more about how our world works, and this book is a solid step in that direction. Just as Hyperspace was a bestseller, I hope TEU can acquaint more people with these fascinating and fundamental developments of science.
So What's In It For Me?
Very simply, a better understanding of how our world works, and little pain in getting there. There's something to be said for enjoying physics!
Purchase this at ThinkGeek.
Table of Contents- Preface
- Part I: The Edge of Knowledge
- Tied Up with String
- Part II: The Dilemma of Space, Time, and the Quanta
- Space, Time, and the Eye of the Beholder
- Of Warps and Ripples
- Microscopic Weirdness
- The need for a New Theory: General Relativity vs. Quantum Mechanics
- Part III: The Cosmic Symphony
- Nothing but Music: The Essentials of Superstring Theory
- The "Super" in Superstrings
- More Dimensions Than Meet the Eye
- The Smoking Gun: Experimental Signatures
- Part IV: String Theory and the Fabic of Spacetime
- Quanutm Geometry
- Tearing the Fabic of Space
- Beyond Strings: In Search of M-Theory
- Black Holes: A String/M-Theory Perspective
- Reflections on Cosmology
- Part V: Unification in the Twenty-First Century
- Prospects
- Notes
- Glossary of Scientific Terms
- References and Suggestions for Further Reading
- Index
Not to start an epistemiological debate, but I wonder how you define "right" and "wrong" in the context of contemporary science?
I try not to :-) I don't think it's possible to prove a scientific theory (yet, anyway) but thinking about it, I would (for example) consider Einstein's theory as more correct, more "right", than Newton's...even though, in Newton's time, Occam's razor would have led me to support Newton.
Heh...I'm not even sure if that's what you were asking; I looked to my .sig for guidence and now my head hurts...
dylan_-
--
Igor Presnyakov stole my hat
Is there any evidence for string theory?
Well, according to the book (read it and enjoyed it), the problem is trying to find something to predict that could be tested.....the strings are so small that it's very difficult to show that they aren't points. As far as Occam's razor goes, string appears to be the more elegant theory, but the new theory tends to have the burden of proof....anyway, all Occam's razor is is a rough guide on what to work with...it doesn't actually have anything to do with what's "right" or "wrong"...
dylan_-
--
Igor Presnyakov stole my hat
As to the argument about Occam's Razor, frankly you're right. If String/M-theory can't explain what we want it to, or if there is a simpler theory that explains the same things, then string theory will fall to this other theory. But at the present time there is no other theory that holds half the promise of string theory. General Relativity can't explain Quantum Mechanics, and Quantum Field Theory, which is so good for electromagnetism, the weak force, and the strong force, can almost certainly not explain gravity. (and has some unsatisfactory properties for other reasons - like 30-odd "arbitrary" parameters. We'd like to know why these 30-odd parameters have the values they do)
String theory is promising because it has a very large space of possible configurations. In other words, there are billions of ways you can tune all the parameters in string theory to end up with different "universes". Many of the he generic properties of these universes have already been verified to correspond to our own. In some sense "solving" string theory will someday be a game of trying out all the possible permutations of configurations, and finding one that works. But for now we also need to concentrate on understanding the fundamentals of it.
It is important to note that General Relativity, and Quantum Field Theory must be derivable out of string theory for it to be a viable theory. (This is generically how physics works) People have been deriving QFT's and GR out of various string theories for a long time, so it can be done. It's just a matter of finding the right string theory, from which we can derive the electroweak QFT, GR, and the masses of all the particles that we see.
--Bob
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
There's still some argument over whether all particles are influenced by gravity; I seem to remember recently that there is talk of the gravitational lens effect (ie light being affected by gravity) being disproved.
That would be quite a trick. If I remember correctly, one of the measurements used to support relativity was of gravitational lensing of starlight by the sun (mask out the disc and take careful measurements of the apparent positions of stars next to it).
Gravitational lensing studies are also being performed to measure the mass of distant galaxies (by looking at multiple images of even more distant galaxies). If gravitational lensing didn't exist, it would have been noticed in a big way by these studies.
As far as anyone's been able to determine, photons are constrained to follow the geometry of spacetime like everything else. Can you give a citation for the articles that you refer to that propose otherwise?
Is there any evidence for string theory? I was under the impression that this is somewhat-elegant-but-not-great-friends-with-Occams 's-razor theory which is a long, long way from getting any empirical support.
Don't hold your breath. It's not the sort of subject where empirical evidence is easily available. Nowadays string theory has evolved into m-theory, which basically adds another dimension to our already burgeoning universe. Check out here
anyway, all Occam's razor is is a rough guide on what to work with...it doesn't actually have anything to do with what's "right" or "wrong"...
Not to start an epistemiological debate, but I wonder how you define "right" and "wrong" in the context of contemporary science? Specifically, how can you tell if whether science theory is "right"? Is is possible to *prove* a science theory?
Kaa
Kaa
Kaa's Law: In any sufficiently large group of people most are idiots.
Comment removed based on user account deletion
A friend of mine purchased this book for me, swearing it was the most mind-expanding read he had enjoyed for a long while. Unfortunately, I was disappointed.
I have some familiarity with relativistic phsyics, having read Einstein's own attempt at popular science, "Relativity", and quantum physics from "The Dancing Wu Li Masters" Contrasting these works with "The Elegant Universe", I found that Greene never hit the right stride for a book that purports to make complex scientific topics clear.
Crucial issues that lead to the birth of quantum physics like the ultraviolet catastrophe and the photoelectric effect are given a shallow treatment that barely suffices to convey why turn-of-the-century was in such turmoil. Greene even manages to make the famous double slit experiment seem irrelevant and confusing. I felt that if I had studied these topics in college, I would not have comprehende why Greene chose these topics for inclusion in his book.
On the relativistic front, well, Greene completely eschews equations in that section, which was a mistake. Without the dilation equations, the reader gets no sense of *why* things stretch and slow down as they approach the speed of light. You only have to take Einstein's word on it.
Having seen how his coverage of these two topics was lacking, I am suspicious that the discussion of string theory (the reason the book was written) is probably equally weak. Having read the book, I doubt I could speak intelligently about those topics, as I sometimes can do with quantum physics and relativity, having had only the minimum of study described above.
If you enjoy reading about science rather than actually understanding science, this book may be for you. All others I advise to pick up a college freshmen physics text - you'll find it far more gratifying.
-konstant
Yes! We are all individuals! I'm not!
-konstant
Yes! We are all individuals! I'm not!
While I haven't had a chance to read the book yet, Brian Greene did teach my intro physics class. Little did we, as freshmen, realize that most of the classes we would take in the future would compare to Brian's class. He explained things clearly, had time for students, and had the hardest damn tests I've ever taken. All in all, I think that he may be the coolest physisist since Feynman.
Another equally fascinating and much more entertaining look at the universe can be had through a book written by Leon Lederman, called "The God Particle."
Though older than TEU, it only lacks proof of the sixth quark. Otherwise, it matches TEU in a understanding and insight.
However, easily its main selling point is Lederman's status as an experimental physicist. Unlike "The Elegant Universe" and "A Brief History of Time" (by Stephen Hawking, also a phenomenal book, though even more focused on the layman), "The God Particle" thoroughly examines what we know in physics, not just what we suspect, and does so in an amazingly entertaining way, yet without pandering to the lowest common denominator. You may feel inclined to skip the first couple chapters that deal with the development of classical physics (which each of these books do exhaustively). "Schroedinger's Cat" and "Schroedinger's Kittens" are both excellent books that cover quantum mechanics very concisely, and are a nice alternative to the complete anthology presented in "The Elegant Universe."
I have read all of the books I've mentioned here, but IANAPMY (I am not a physics major, yet), so I don't vouch that they are completely current in the realm of theoretical physics today. They are all thoroughly enjoyable, entertaining (no kidding, laugh out loud) and educational, and I highly recomment them.
Just ignore the sig, it's not supposed to be flaimbait.
Error loading humorous sig.
Don't forget that the average slashdot reader may like the extra math. I am interested in this book because of all the math that you and the reviewer didn't care for.
When they reviewed the Linux Source Code Commentary book, nobody said, "There's too much code in this book." Mathematics is the fundamental code of the universe, and IMHO there can never be too much of a reference to it. I am a big Linux fan, but the Math code that controls the universe is 10^6 times more elegant and beautiful.
Some good Math references...
Lang, Algebra
Gleick, Chaos
Arnold, Mathematical Methods of Classical Mechanics
Churchill and Brown, Complex Variables and Applications
Andrews, Number Theory
--
Thad
Thad
Particle physics has more immediate worries on its hands. String theory is a lot like several of the (current) developments in particle physics (ie: supersymmatry). It's elegant, and solves a bevy of problems, yet there is no experimental proof for them -yet-.
The upgrades to the Tevatron at Fermilab, and the completion of the Large Hadron Collider at CERN in 2006 will provide energy scales large enough to create and observe superpartners. (And perhaps the Higgs boson, if you're familiar with the Standard Model). On the horizon after that are are the Very LHC, or a giant linear accelerator -- then, and only then, are we going to get even close to start solving mysteries like this empiracally.
Bear in mind though, that Maxwells equations (and even Newton's) equations went unsupported for years (even almost a century) before they were widely accepted. Most of modern particle physics is young by comparision, and the energy barriers are much greater, so its not surprising there is no evidence so far.
I sorted out my confusion on this FAQ web site.
/physics/relativity.html
I made it a few pages down the FAQ, and I'm afraid I have to say that it's one of the worst that I've ever seen. The author's argument seems to amount to "Well, you can describe the universe mathematically using four dimensions, but because I only see three of them this is purely bunk.".
At this point, I stopped reading.
In point of fact, if you want to see the effects of space being four-dimensional, you need only look at two reference that are moving quickly with respect to each other. The time and space directions measured by observers in each frame are different - this is the Lorentz transform (if I remember the term correctly). Space in one frame corresponds to a skewed space-and-time axis in another frame.
This has been verified experimentally by very careful measurements of atomic clocks moving at different speeds with respect to each other. A more dramatic illustration is measuring the decay times of unstable particles moving at different speeds. As they approach the speed of light, the lifetime as measured by the observer gets longer. This is called "time dilation", and is one of many effects caused by the "time" and "space" axes not being the same for observers moving with respect to each other.
You can find a very good FAQ on relativity here:
http://math.ucr.edu/home/baez
This links to a FAQ on general physics, and many other FAQs that may be of interest.
Is there any evidence for string theory? I was under the impression that this is somewhat-elegant-but-not-great-friends-with-Occams 's-razor theory which is a long, long way from getting any empirical support. Yet this review mentions accumulating evidence for the sting theory. Did I miss something? (and no, accumulating papers and preprints are not evidence).
Kaa
Kaa
Kaa's Law: In any sufficiently large group of people most are idiots.
That's a long post, but I think I may be able to help ;-)
In a nutshell, Cole's Notes edition, how does gravity work, according to science's current understanding?
That's an incredibly vague question. General Relativity describes gravity as being a property of the curvature of spacetime. Wherever there is a mass, it will "bend" spacetime around it and cause the effects of gravity. This interpretation works very well and is consistent with all experimental data, but it still leaves out some questions. What is spacetime? How does gravity bend it? And so on.
Quantum mechanics takes a different approach. It says that all the fundamental forces (strong nuclear, weak nuclear, electromagnetic, and gravity) are caused by the exchange of particles, and this of course includes gravity. The strong nuclear force is caused by the exchange of gluons, the weak nuclear force is caused by the exchange of W+, W-, and Z bosons, the electromagnetic force is caused by the exchange of photons, and gravity is supposed to be caused by the exchange of gravitons. Notice I say "supposed", because there is currently no direct evidence whatsoever for the existence of the graviton. Just about every modern physicist believes it must exist simply because all the other forces are caused by the exchange of particles. If gravity somehow operated by a different method it would pretty much ruin any chance of coming up with a TOE
We are capable of creating and breaking nuclear bonds, both in (un)controlled fission and uncontrolled fusion. We're pretty capable of transmuting elements from one to another; U-238 into Am-241 for smoke detectors, etc., even if these transmuted elements are just by-products of other processes. Is it gravity or is it gluons that hold together the protons in a nucleus despite their repellant similar charges? (Especially fascinating in some isotopes of helium and lithium that lack neutrons.) Even if we don't know, we have some control over the makeup of an atom.
First of all, it is definately gluons, or rather the strong nuclear force which is caused by the exchange of gluons among so-called "colored" particles (That has nothing to do with what most people think of as "color". Don't worry about it for now.), which cause the nucleus of the atom to be held together. The effect of gravity is incredibly weak when compared to the electromagnetic force and it could not possibly hold a nucleus together. The electromagnetic force, on the other hand, is rather weak when compared to the strong nuclear force.
Anyway, that's besides the point. You're talking about our "control" over the fundamental forces. But what does it mean to "control" a force? You use nuclear fission as an example, but all we do there is take some radioactive material, stick it all together, and let nature run its course. Is that really "controlling" it? Can I say that I am "controlling" gravity when I ride a rollercoaster? Just something to think about...
I'm not sure what this means, either. Fission and fusion relate to changes to the makeup of the nucleus; the net number of protons in the nucleus will change the number of electrons required to achieve equilibrium and therefore will affect the chemical properties of the element. Is it possible that weak nuclear refers to chemical properties brought on by the number of electrons required for equilibrium and therefore determines which other elements will chemically react with this element? Or is weak nuclear referring to things like photon emissions as electrons drop shells?
First off, everything you talked about is dealing with the electromagnetic force. The weak nuclear force is a strange force. It's not really responsible for a "force" in the sense of what we normally think of as a force. What it is responsible for is various processes which occur in the nucleus of an atom. The classic example is beta decay. Before I begin I should note that I may have the neutron and the proton reversed, as I can never remember which is udd and which is uud. What happens in beta decay is that a down quark inside a neutron changes to a up quark, converting the neutron (which consists of an up quark and two down quarks, udd) into a proton (uud). In the process, an electron and an anti-electron neutrino are released. The weak force is what is responsible for this process. The quark actually changes by emitting a W- boson, which immediately decays into the electron and the anti-electron neutrino. This is not the only process which the weak nuclear force is responsible for, but it is the only one I can come up with off the top of my head.
The emissions of radiation I see as being caused by the stronger nuclear forces. As the nucleus gets larger (and gets seeded with neutrons in the right ratios), it becomes more unstable, more likely to break the ?gravity? or ?gluonic? bonds that attach the similarily-charged protons which indirectly control the chemical properties. Net effect: fission occurs, energy is released. Alpha particles are just positive helium ions, beta particles are just electrons (that get shot from the positive nucleus, go figure) and gamma rays are photons of energy released as an infinitesimally small quantity of matter in the nucleus is converted to energy. So, since nuclear radiation is occuring very much as a factor of the strong bonds that hold a nucleus together, is radiation really a part of the weaker nuclear bonds? I must be missing something; I fail to understand.
You're actually pretty close to the mark with the radiation thing. It so happens that as the nucleus of an atom becomes larger and larger the strong nuclear force has difficulty holding it together and the nucleus become unstable. I do not remember the exact reason why this is so, but I believe it has something to do with the short-range nature of the nuclear forces (unlike electromagnetism and gravity, which continue on theoretically forever growing closer and closer to zero as distance increases, the nuclear forces actually have a "range", which is why their effects are limited to the nucleus of an atom), however don't quote me on that. Alpha particles are basically just pieces of a nucleus that get spit out, they're not that interesting ;-) . I talked about beta decay when I discussed the weak force. I should note something about Gamma particles however. Basically, what happens with a Gamma particle is that a neutron or a proton in the nucleus of an atom becomes "excited", similar to how electrons circling the nucleus become "excited" all the time. However, the neutron of the proton are controlled primarily by the strong nuclear force, which is a great deal stronger than the electromagnetic force, and so it takes significantly more energy to exicte them than it takes to excite an electron. Generally, the excitement of a neutron or a proton is caused by some other nuclear interaction (Alpha or Beta decay, being hit by a free neutron, colliding with another nucleus [fusion]) because that is the only way to get enough energy to excite a proton or neutron. When the proton or neutron returns to its previous "energy level" (we don't normally think of protons and neutrons as having energy levels, but really they do) it releases a photon, only this photon has far more energy than any photon released in normal chemical processes.
I really don't understand what you are asking in the last part of your paragraph there. Radiation can be caused by the strong nuclear or weak nuclear forces, as discussed above. It all depends on the type of radiation really.
Anyway, I'd love to continue this discussion with gravity (which I know is what you were asking about in the first place), but I've spent too much time talking already and I think my boss will be upset if I don't actually do some work today. Oh well, I hope I've cleared some things up.
I am not an idiot. Please use my name to email me.
"That's right, I'm quoting myself."
-Upsilon
Well, it's not really proof of superstring theory as such, but superstring theory has been used to proof Bernstein's (?) hypothosis that the surface area of a black hole is proportional to its entropy, which had resisted proof by other methods for 30 years. There's more about the proof in the book, which is well worth a read.
So no, nothing definite, but that's one of the goals of superstring theorists - to look for low-energy consequences of the theory that can be tested within the forseeable future. Until then, the theory is in an experimental limbo, but it does seem too good not to be true. But that is purely my opinion, and some quite famous physicists would disagree :)
Covering the same subject matter, but somewhat more accessable for the layman is The Whole Shebang : A State-Of-The-Universe(s) Report
I've read both, and enjoyed The Whole Shebang quite a bit more, and they really do cover largely the same material, even if The Whole Shebang is maybe 2 years older... it includes quite a bit more cosmological material as well.
Its available from amazon here
DrLunch.com The site that tells you what's for lunch!
You can argue that theoretically, Newtonian physics can't fully explain the physics of a 90mph pitch of a baseball, but if you try to pull out transformations to take relativity into account, your corrections will be many orders of magnitude too small to affect a significant digit. Newton deserves the same respect we give Einstein, who may someday be just as "wrong".
"What I cannot create, I do not understand."