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Elegant Universe Airs Tonight on PBS

Posted by michael on from the book-learnin' dept.

fatarfy writes "USA Today among others has an article discussing tonight's presentation of Brian Greene's Elegant Universe, which discusses String Theory. It airs on PBS. From the article: 'The two segments of the show turn their spotlights on a crisis in physics, one invisible to the general public but increasingly embarrassing to the discipline. Simply put, Einstein's unbelievably accurate explanation of gravity, known as general relativity, is completely out of whack with the equally accurate explanation of electromagnetism, radioactivity and atomic forces known as quantum mechanics. The theories are mankind's most fundamental views of verifiable reality, and the disagreement means that something important about the universe eludes our understanding.' Sounds like it's worth watching."

69 comments

  1. For sure, more than one thing *grin* by Futurepower(R) · · Score: 4, Funny


    "... something important about the universe eludes our understanding..."

    Exactly correct, but also unintentionally funny. I'm guessing something is more accurately 100,000,000 things.

  2. 2nd post by Futurepower(R) · · Score: 0, Redundant

    Wow, I accidentally got an on topic frost pist.

  3. classical/statistical - quantum reconciliation by Doc+Ruby · · Score: 2, Interesting

    At least one physicist, Garnet Ord, has extended the classical/statistical physical model of phenomena to include quantum mechanics. Perhaps similar work with Relativity can produce a grand reconciliation?

    --

    --
    make install -not war

  4. String Theory by Academy+Girl · · Score: 5, Interesting

    The thing I find funny about critics of string theory is their objection to the idea that there can be multiple dimensions beyond the three dimensions people can perceive. This is where philosophy and physics should intersect -- right at Kant, who pointed out that you cannot understand the world, only your perception of the world. Now, whether or not you agree with Kant, the point is that you, at least, shouldn't be limited by your perception of the universe. It seems plainly obvious that just because people can only perceive three dimensions, the universe certainly doesn't have to be contained by that premise.

    1. Re:String Theory by Vaevictis666 · · Score: 1, Insightful

      I don't know about you, but I have no problem perceiving four dimensions (the fourth being time). Still a very valid point that we shouldn't limit ourselves to an arbitrary value based on perceptions though :)

    2. Re:String Theory by citoc · · Score: 5, Insightful
      The issue isn't the inability to understand higher dimensions, most critics have an issue with the inability to observe higher dimensions. If higher dimensions exist, why don't we observe things moving in them? The only reason String theory predicts higher dimensions is because the matrix it uses (the math kind not the movie kind ;-) can only be solved in higher dimensions. So the explanation that these higher dimensions must in fact exist on a plane smaller than our observable limit (roughly a proton) seems a bit arbitrary to some (many).

      Surely we can agree that the gap between quantum and relativity needs to be filled, but going off on a whole set of random assumptions based on what needs to be true to solve a little math issue might not be the best approach. Then again, look what it did for Einstein... Of course the difference there was that his predictions were actually observed...

    3. Re:String Theory by Bootsy+Collins · · Score: 3, Insightful

      The thing I find funny about critics of string theory is their objection to the idea that there can be multiple dimensions beyond the three dimensions people can perceive.

      Who fits that description, though? I know lots and lots of theorists in elementary particles and fields who are critics of string theory, but not for that reason. Indeed, it'd be odd if so, since mainstream particle theorists have been building models incorporating additional "dimensions" since the 1950s (e.g. isospin models in particle and nuclear physics).

      The real criticism of string theory is much more fundamental. In order to be taken seriously -- indeed, to even be considered scientific -- a physical theory should be falsifiable. There should be some experiment I can do or observation I can make where, if it doesn't come out the way the theory says, then the theory is wrong. But since string theory describes the nature of things at energies around the Planck scale -- 19 orders of magnitude greater than the mass of the proton, or 16 orders of magnitude higher than the best particle accelerators we've built -- how do you test the theory? String theorists say that they simply haven't been clever enough yet to figure out how to make unique predictions at potentially experimentally accessible energies, but that they will be; and maybe they're right. I hope they're right, because string theory is beautiful in a lot of ways (at one point, I wanted to do string theory). But they've been saying that for 20 years now, since Green (no relation), Schwarz and Witten's stuff.

    4. Re:String Theory by jazman_777 · · Score: 2, Interesting
      In order to be taken seriously -- indeed, to even be considered scientific -- a physical theory should be falsifiable.

      Unless, of course, it happens to be _true_.

      --
      Slashdot: Failed Car Analogies. Amateur Lawyering. Anecdote Battles.
    5. Re:String Theory by *xpenguin* · · Score: 1

      Ever heard of the fourth spacial demension?

    6. Re:String Theory by Bootsy+Collins · · Score: 4, Informative

      > In order to be taken seriously -- indeed, to even be considered scientific
      > -- a physical theory should be falsifiable.

      Unless, of course, it happens to be _true_.

      I'm not sure whether you meant this reply as a joke or not; the moderation suggests so, and perhaps my humor detector is even worse-off than it usually is. But it seems possible to me that your reply is serious, so (being both a physicist and an educator) I can't help myself . . .

      Perhaps the most widely misunderstood property of modern science is that no proposition, no scientific theory, is ever proved to be absolutely true. No matter how much evidence you accumulate in favor of some theory or model, there's always the possibility that next week someone's going to come up with an experimental or observational result that requires that theory's revision or even outright rejection. Scientific theories can only be proven false; they can never be proved true.

      "Yeah, yeah," you might be saying, "but I wasn't talking about whether theories can be proved true or not; I was talking about whether or not a theory actually is true. After all, even if we can't ever know with 100% certainty that a particular theory is true, it may still be true." Yes, indeed. But that's irrelevant to my original point, the one to which you replied. Since we cannot ever know with certainty whether any theory we put forward is absolutely true, and thus any theory is always subject to scrutiny, our requirement that the theory be falsifiable -- that it be possible to conceive of an experimental or observational result which would rule the theory out -- still stands.

    7. Re:String Theory by key45 · · Score: 2, Informative

      I heard Greene on NPR's Science Friday He says that some recent work on the theory predicts some effects which may be testable in a few years by the newest generation of "atom smashers" currently under construction at CERN and elsewhere.
      We may get to that "falsifiable" stage relatively soon...

    8. Re:String Theory by Bootsy+Collins · · Score: 2, Interesting

      I heard Greene on NPR's Science Friday He says that some recent work on the theory predicts some effects which may be testable in a few years by the newest generation of "atom smashers" currently under construction at CERN and elsewhere.
      We may get to that "falsifiable" stage relatively soon...

      Unfortunately, I'm not so optimistic. At least, not in general.

      To explain why . . .in string theories, one of the things that has to be explained can be oversimplistically described as "where are all the other spatial dimensions now?" Why are three spatial dimensions macroscopic (effectively, observable by us) and all the others not? In the very early universe/at extremely high energies, all the dimensions should have been equal; but somehow, three of them expanded into the universe we know while the others stayed small. How this is done mathematically is referred to as "compactification" (and for anyone out there who's a math graduate, it's the same compactification of manifolds as you encountered in topology).

      Some string theories have, as a result of the compactification, one of the compactified dimensions actually being comparatively large, with a characteristic scale of about a millimeter or a micron or something like that. These "one large dimension" models look like they would have observable consequences for experiments at accessible particle accelerator energies; and so it's possible that such models could be falsified. But that's not the same as falsifying string theory; it's only the possibility of falsifying a class of models within string theory.

    9. Re:String Theory by Academy+Girl · · Score: 1

      What if the issue is not so much that the higher dimensions can't be resolved as that we just don't know how to do that yet. I agree with your Popperian point; on the other hand, I wouldn't want to throw the baby out with the bathwater.

    10. Re:String Theory by Bootsy+Collins · · Score: 1

      What if the issue is not so much that the higher dimensions can't be resolved as that we just don't know how to do that yet.

      Oh, absolutely; I'd hoped that I'd communicated that possibility in my post. It's quite possible that we just haven't yet been clever enough. Certainly that's the opinion of most string theorists; however beautiful the theory may be, they are physicists and they do want what they're doing to have some relevance to the real world. I hope string theory is right; I think it's cool. But if you're not a string theorist, but have been following string theory over its lifetime, it's hard to be enthusiastic at this point; the string theory community has been saying "observational predictions are right around the corner" for a long time now. That doesn't make them wrong; but, again, it's hard to be enthusiastic.

    11. Re:String Theory by squiggleslash · · Score: 3, Funny
      Apparently most washing machines are four dimensional objects, which is why you keep losing socks in them.

      In order to balance, one of the two opposing socks is pushed away from the other in the unseen plane, balancing the washing machine but, regretfully, making that sock unobtainable. Many scientists believe that at the opposing side of the washing machines is a large black hole, into which the socks go, which in turn is unbalanced as a result causing each sock to remove a small amount of mass from the hole on entry.

      This is why you get holes in your socks. It's symmetry.

      --
      You are not alone. This is not normal. None of this is normal.
    12. Re:String Theory by mrgeometry · · Score: 2, Informative

      http://mathworld.wolfram.com/Calabi-YauSpace.html

      The above-linked page has a rough definition of the kind of space a 10-dimensional string theory might live on. I don't know why they take a product $M \times V$ --- why not allow a more general bundle of C-Y 3-folds?

      The imaginary version of string theory which exists only in my mind has the universe as a bundle of Calabi-Yau 3-folds over $M$ (a real 4-manifold with a Minkowski metric, or something like that... anyway, a $(3,1)$ form --- that's a Minkowski metric, right???). That's 10 dimensions. The 11- or other-dimensional kinds of string theory, I have no idea.

      Being an algebraic geometer (in training), I think of a C-Y 3-fold as a smooth projective complex 3-dimensional variety, or manifold, with trivial canonical bundle.

      Well, that's the space. Then all kinds of crap happens *in* the space, with strings and stuff, and that's a whole nother story...

    13. Re:String Theory by mrgeometry · · Score: 2, Funny

      I'm stupid. I meant to say also the following. What if we specify an ample line bundle L on the C-Y 3-fold X; this is a polarization of X? Ample in algebraic geometry is the same as positive in several complex variables.

      Among other things, this gives a *volume* of X, a positive real number, which is the same kind of volume that we're used to thinking of---like a cube with sides all equal to 1 has volume 1, etc. The Griffiths and Harris book would explain this better than I can.

      The volume is something like $L^3/sqrt{2\pi}$, or something like that. Since it's physics, there are some kind of units. If this volume is small enough (i.e. measured in small enough units), it might suggest a reason why we can't move "along" the six dimensions corresponding to the C-Y 3-fold bundle: something small like an electron already fills up the tiny volume.

      Ah, whatever. I'm just talking out my butt.

    14. Re:String Theory by jazman_777 · · Score: 1
      I'm not sure whether you meant this reply as a joke or not; the moderation suggests so, and perhaps my humor detector is even worse-off than it usually is. But it seems possible to me that your reply is serious, so (being both a physicist and an educator) I can't help myself . . .

      I was serious and being funny at the same time. Two words: David Stove. Ha ha ha ha...

      Scientific theories can only be proven false; they can never be proved true.

      So no scientific theories are true--they can only be false.

      --
      Slashdot: Failed Car Analogies. Amateur Lawyering. Anecdote Battles.
    15. Re:String Theory by GrassyKnowl · · Score: 1

      What if there is only the dimension that we are familar with, but the time scale is different at the quantum level and the continuum level?

      What if at the quantum level, energy can propagate faster than the speed of light thus having the appearance of being in more than one place at one time giving the illusion of multiple dimensions.

    16. Re:String Theory by Curtman · · Score: 1

      IANAP, but a humble aspiring programmer who finds all this very interesting. It seems to me that the 4th dimension is observable by us, but our perspective with respect to it cannot be altered by us the way we can change our perspective on the first 3 by moving around. The part of the show with the light post appearing as a 2D picture made up of lines was particularly interesting to me. It wasn't until we changed our perspective in 3D space that even the 3rd dimension became apparent. Its a matter of convenience that we are pushed along the 4th dimension, that we even realize it exists.

      My question would have to be, how can we begin to test the existence of the higher dimensions until we can either influence our position with respect to them, or at least observe some change with respect to them?

    17. Re:String Theory by JabberWokky · · Score: 1
      Arg. This always drives me nuts and is my pet peeve.

      There are only three observed spatial dimensions. There is one temporal dimension. In many equations, you can flip back and forth among all four equally, but that does *not* mean that time is a coordinate system that is the same as the three spatial dimensions!

      In fact, if you watch the utterly redundant and repetative and repetitous Nova episodes (how many times did he tell us that there are these three and that one force and they don't reconcile?), you'll note that several of the interviewed physicists referred to three plus one, rather than simply calling them four. As a mathematical model, time can be treated as a dimension. As a functional aspect of observation, it is not the same as the three spatial dimensions.

      String theory adds new non-linear spatial dimensions (like circles versus lines).

      --
      Evan

      --
      "$30 for the One True Ring. $10 each additional ring!" -- JRR "Bob" Tolkien
    18. Re:String Theory by cpeterso · · Score: 1


      who knew Bootsy Collins knew so much about particle physics?!! :)

      --
      cpeterso
    19. Re:String Theory by srussell · · Score: 1
      • In order to be taken seriously -- indeed, to even be considered scientific -- a physical theory should be falsifiable.
      Unless, of course, it happens to be _true_.

      I think you misunderstood what he was saying.

      By "falsifiable", he was saying that a good theory is one for which you can contrive an experiment that is sufficient to prove the theory false. The idea being that the experiment failing lends credence to the theory.

    20. Re:String Theory by pmz · · Score: 1

      Apparently most washing machines are four dimensional objects, which is why you keep losing socks in them.

      Ask your spouse if he/she keeps a secret drawer with all the unmatched socks in them. My wife pointed out this magical drawer in our house, and it was as if I had finally come to understand the universe. String theory be damned, someone just ask their wife!

      --
      Healthcare article at Kuro5hin
    21. Re:String Theory by fragamus · · Score: 1

      The reason that string theory hasn't been observed is that it would require a particle accelerator the size of a solar system to generate the required high energy conditions. Some astronomers are attempting to use nature's particle accelerator and observe astronomical phenomena that are predicted by string theory.

    22. Re:String Theory by lethe1001 · · Score: 1
      I don't know why they take a product $M \times V$
      because they want it to describe our universe. so some part of spacetime has to be 4 dimensional minkowski space. that s M. the rest is V.

      why not allow a more general bundle of C-Y 3-folds?
      spacetime is not a bundle. it is just a manifold.

      The imaginary version of string theory which exists only in my mind has the universe as a bundle of Calabi-Yau 3-folds over $M$ (a real 4-manifold with a Minkowski metric, or something like that... anyway, a $(3,1)$ form --- that's a Minkowski metric, right???)
      it is not a bundle! the spacetime is a 10 dimensional manifold, not a 4 dimensional base space with a 6 dimensional fiber.

      by the way, a metric is a (0,2) tensor, not a (3,1) tensor, and not a form at all (since it is a symmetric tensor, and forms are necessarily antisymmetric). you are thinking of the signature. the signature of the metric is the number of positive diagonal elements minus the number of negative diagonal elements, in some diagonal basis. for minkowski space, or any lorentzian metric, the signature is 3-1.

    23. Re:String Theory by mrgeometry · · Score: 1

      Yes, of course you're right about the tensor and signature. That was silly of me. Thanks. I think the issue is partly physics terminology vs. math terminology: for me, a form is actually symmetric... I should have been more careful.

      I have to point out, however, that a 6-dimensional fiber bundle on a 4-dimensional space IS a 10-dimensional manifold! Locally it looks like a product, but globally it can fail to be a product. Still, even if it's not a product, it is always a manifold. A product is a specific example of a fiber bundle---a trivial example, in the technical sense of "trivial"... So why can't space-time be a nontrivial bundle?

      Example: a cylinder in R^3 is a bundle of lines over a circle. It's trivial---a cylinder is the product of a line and a circle. A Moebius band is **also** a bundle of lines over a circle: to see this, draw a circle down the center of the band, and that's the base space; then all the "perpendicular" lines going edge to edge on the band are the fibers. The Moebius band is non-trivial. This takes some proof, but it's true.

      I am *not* BS'ing this. I know whereof I speak. Many books on topology, such as Munkres, have good explanations of trivial vs. non-trivial bundles.

      Since you allow the base space to be a general 4-manifold M, you might as well allow non-trivial bundles. Locally they will be trivial; locally M is just R^4 (with a tensor field, etc.).

      zach

    24. Re:String Theory by lethe1001 · · Score: 1

      i am aware of the difference between a trivial and a nontrivial bundle. i just am not sure why you want spacetime to be a bundle.

      have to point out, however, that a 6-dimensional fiber bundle on a 4-dimensional space IS a 10-dimensional manifold!
      yes, a 4 dimensional base space with a 6 dimensional fibre is a 10 dimensional manifold. but there are lots of other 10 dimensional manifolds that are not bundles, not even locally. i don t know why you want to restrict spacetime to be a bundle.

      A product is a specific example of a fiber bundle---a trivial example, in the technical sense of "trivial"... So why can't space-time be a nontrivial bundle?
      the property of being a bundle is extra structure that a manifold can have. not all manifolds have this structure. of course, if spacetime is M4xCY3, then it can be made into a trivial bundle rather obviously, but the point is, there is no reason to do this. a product of manifolds is just a product of manifolds. not a bundle.

      Example: a cylinder in R^3 is a bundle of lines over a circle. It's trivial---a cylinder is the product of a line and a circle.
      yes, but you can also make the line the base space of the cylinder, and let each fibre be the circle. this is a totally different bundle, but the same manifold. furthermore, there is no canonical "best choice" of which of these two bundles i should choose, if i want to start calling this cylinder a bundle. since i am only interested in what kind of topology and geometry spacetime has, it makes no sense to choose some bundle structure on it.

      so let s stop talking about bundles. i guess you still want to ask the question why is spacetime M4xCY3 instead of having M4 embedded in the 10 dimensional spacetime in some nontrivial way. i think that s a good question. i donno

    25. Re:String Theory by mrgeometry · · Score: 1

      OK, good point, why have a bundle at all? For one thing, bundles are much easier to deal with than general manifolds---we don't even understand 3-manifolds, let alone 10-manifolds (eg, Poincare conj.). For another thing, if MathWorld says it's a product, and I'm curious about generalizing it, I think it's reasonable to make a small step to fiber bundles, before leaping all the way up to general manifolds. But as you say, the question generalizes up more.

      I hope you don't mind if I pick a nit or two in your post:

      a product of manifolds is just a product of manifolds. not a bundle.

      But isn't it a trivial bundle, in two different ways, as you point out with reference to the example of a cylinder?

      Anyway, most bundles are not trivial, and non-trivial bundles can't be simply "turned sideways" like a product can. I could be wrong, but it seems to me that in the topological category, and maybe in the smooth category as well, "most" bundles have a "unique" bundle structure map (in the sense that any two of them differ by a unique automorphism of the bundle space). On the other hand, spacetimes live in the category of smooth spaces with a tensor field which satisfies some conditions, etc... and in that category, maybe bundle structures are not unique?

      So I was going to disagree with you about non-existence of canonical bundle structures, but actually you're probably right! :-)

      Anyway, I don't mean to argue about fiber bundles per se... Sorry... Thanks for the discussion, it's helped me think through my question a little more carefully than I had originally, and even given me a few new questions to think about!

    26. Re:String Theory by lethe1001 · · Score: 1

      ut isn't it a trivial bundle, in two different ways, as you point out with reference to the example of a cylinder?
      a bundle is a triple (E,M,p). E and M are manifolds, and p is a smooth map from E to M. until i specify a base space and a mapping, i don t have a bundle. if E is a product manifold, there are at least two easy choices to make it into a bundle, but there might be other choices. the point is, until i have made some choice, it is incorrect to say that M1xM2 is a bundle.

      Anyway, most bundles are not trivial, and non-trivial bundles can't be simply "turned sideways" like a product can. I could be wrong, but it seems to me that in the topological category, and maybe in the smooth category as well, "most" bundles have a "unique" bundle structure map (in the sense that any two of them differ by a unique automorphism of the bundle space). On the other hand, spacetimes live in the category of smooth spaces with a tensor field which satisfies some conditions, etc... and in that category, maybe bundle structures are not unique?
      the manifold M1xM2 can be a bundle in lots of ways, 2 of which are trivial. it is not a bundle until i choose such a way. your question about most bundles having a unique bundle structure doesn t quite make sense. do you want to know if most pairs of manifolds admit a unique mapping between them that makes them into a bundle? i think that is clearly not true. i don t even think it is true up to bundle morphisms.

  5. I'm busy tonight by anthony_dipierro · · Score: 1

    Some record it and put it on Kazaa for me.

    1. Re:I'm busy tonight by NanoGator · · Score: 2, Interesting

      "Some record it and put it on Kazaa for me."

      If the television industry were to be a little more forward thinking, they'd do that themselves. They'd put a few commercials in, get paid for it, and it'd be distributed virtually for free. If they maintain a server to make those shows availble with a decent download rate, then they can pretty much insure that nobody's going to edit out the commercials. (If they wanted to be real assholes, they could use Microsoft's Media format and disable indexing on it, thus meaning you can't skip commercials.)

      --
      "Derp de derp."
    2. Re:I'm busy tonight by DJayC · · Score: 4, Informative

      Actually, PBS is allowing you to view the program on the website after both airings. (this week and next week)

      From the site:
      "Immediately following the broadcast of "The Elegant Universe" on October 28th and November 4, watch the entire three-hour special here. Each episode will be divided into chapters and can be viewed with the QuickTime or RealPlayer plug-ins. "

      And the link:
      http://www.pbs.org/wgbh/nova/elegant/program.html

    3. Re:I'm busy tonight by anthony_dipierro · · Score: 2, Funny

      We're talking about PBS here. It's really easy to skip the commercials already, since they're not embedded in the program.

      Of course, if they offered it for download on the internet, they wouldn't sell as many DVDs for $20.

      Whatever, my tax money is already paying for the program. Please, someone record this and put it on Kazaa for me.

    4. Re:I'm busy tonight by hackwrench · · Score: 1

      But in this case it's PBS, so it should be OK.

    5. Re:I'm busy tonight by anthony_dipierro · · Score: 1

      Awesome. Thanks a lot for the link.

    6. Re:I'm busy tonight by NanoGator · · Score: 1

      "Of course, if they offered it for download on the internet, they wouldn't sell as many DVDs for $20."

      To be fair, VCRs/Tivos and seeing the show on TV as it airs aren't creating less of a risk for that. At least, in this case, somebody who didn't hear about the show until after it was aired would have a fair shot at watching it.

      --
      "Derp de derp."
    7. Re:I'm busy tonight by dogbowl · · Score: 0, Offtopic

      Just send me your Replay ID

      --

      These pretzels are making me thirsty.
    8. Re:I'm busy tonight by Anonymous Coward · · Score: 0

      Look around, I saw a program that will re-index wmv files. (I'm sure M$ would find it violates DRM/DCMA)

    9. Re:I'm busy tonight by Anonymous Coward · · Score: 0

      Just watched it last night. It was two hours and between the hours my replaytv started skipping commercials. What's worse, it didn't skip the "ads" for Elegant Universe. They repeated every idea from the first our, the told all about the next hour. Then the next hour started by repeating the first our. If the cut out the redundant stuff, the show would fit in about 45 minutes. They said thinks like "theory of the big and theory of the small dont' agree" over a dozen times. I'd like to see an edited version on Kazaa.

    10. Re:I'm busy tonight by LunaticLeo · · Score: 1
      FYI, the federal contribution to PBS thru CPB (Corperation for Public Broadcasting) is less than %14 (see this link ) .

      Now there is also State contributions to individual PBS affiliated public broadcast stations. I don't know what the aggregate State contribution to all of Public Broadcasting in the USA.

      --
      -- I am not a fanatic, I am a true believer.
    11. Re:I'm busy tonight by Anonymous Coward · · Score: 0

      Now if only someone would "glue" these together, convert it to a more standard format, and make it available for download via P2P? :)

    12. Re:I'm busy tonight by anthony_dipierro · · Score: 1

      Give me $250 million a year and a broadcast license and I'll gladly make the remaining 86% myself.

      It's a waste of taxpayer money, and anything developed by the company should be 100% copyright free.

  6. embarassing? by TwistedGreen · · Score: 2, Interesting

    The two segments of the show turn their spotlights on a crisis in physics, one invisible to the general public but increasingly embarrassing to the discipline... general relativity is completely out of whack with the equally accurate explanation... known as quantum mechanics.

    How is this an embarassment? It's a fascinating puzzle to have uncovered! Once we nix this dilemma, we'll have the most comprehensive understanding of the physical universe ever before achieved! But it's embarassing that we've already gotten this far? Whomever thinks that does not have an accurate understanding of the nature of science.

    1. Re:embarassing? by pbox · · Score: 1
      Once we nix this dilemma,
      A famous (almost, but not really) last word. You like the physics dude at the end of 19th century (I think he was French?) who said: Once we nix this dilemma (ie. why does the photographic paper darken when uranium is placed on it) we will have a complete knowledge of the Universe. A-bomb, relativity and holograms are just a few that came right afterwards.
      --
      Code poet, espresso fiend, starter upper.
    2. Re:embarassing? by TwistedGreen · · Score: 1

      Well, I didn't say that we'd have a complete understanding. I said that ...we'll have the most comprehensive understanding of the physical universe ever before achieved.

      This will be a major step towards a unified physical model, but it won't necessarily be the final one.

    3. Re:embarassing? by Alsee · · Score: 1

      How is this an embarassment? It's a fascinating puzzle to have uncovered!

      It is an "embarassment" because this puzzle was uncovered decades ago. Not only haven't we made any real progress on it, we haven't even been able to dream up an experiment to begin to explore the problem.

      We have come up with experiments to test Relativity and the results have been exactly right to unimaginable precision. We have come up with experiments to test Quantum Mechanics, and the results have been an exact match as well.

      The problem is that Relativity and Quantum Mechanics fundamentally conflict with each other, and we can't think of a single experiment we can do to explore that confict. We've hit a glass wall dividing them, and that wall hasn't signifigantly budged in decades. In order to climb that wall we need to find some bump or crack on one side or the other to grab onto. The problem is that both theories are "too perfect", both sides of the glass wall are flawless.

      -

      --
      - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
  7. If you already plan to watch Nova... by node+3 · · Score: 5, Informative

    Don't try too hard to find "Brian Greene's Elegant Universe" in your local listing. Instead, just watch Nova as planned, as that's the show which will be covering the topic. Part one is tonight. Part two is next week.

    I don't know why the article (at least), or the headline (even better) didn't mention this. It's sort of the inverse of "The Lone Gunman are Dead".

    Yes, it's in one of the seven links. Did you click all seven? I didn't.

    1. Re:If you already plan to watch Nova... by fillmore · · Score: 1

      8 links. And no, I didn't click all of them. :)

    2. Re:If you already plan to watch Nova... by babbage · · Score: 1
      Don't try too hard to find "Brian Greene's Elegant Universe" in your local listing. Instead, just watch Nova as planned, as that's the show which will be covering the topic. Part one is tonight. Part two is next week.

      Actually, checking local listings is probably a good idea: WGBH & sister stations in Boston & New England broadcast the first two parts back to back last night, and will be repeating these two several times over the next week. The third part is scheduled for the week of 4 November.

      It probably wouldn't be a bad idea to look up $your_city tv listings on Google, or buy a copy of your local newspaper. I realize that this is too late for last night's show, but if WGBH is typical (okay, so they produced it, they have an interest in letting lots of people see it, but still), your local PBS affiliate may be doing one or more re-broadcasts over the next few days.

      --
      DO NOT LEAVE IT IS NOT REAL
  8. More information by daigu · · Score: 2, Informative

    It's a bit dated, but this bibliography has some of the more interesting works in the field.

  9. book; better book by bcrowell · · Score: 2, Insightful
    I guess I'm just an intellectual snob, but I can't see tackling a difficult subject like string theory by watching a TV show. The thing that always bugs me about TV is that I can't turn the page when I want to, either forward or backward!

    The TV show is based on a book of the same title, which I've read. I don't think it's the best introduction to the subject of quantum gravity, because it's all predicated on string theory, which is only one possible candidate for a theory of quantum gravity. Actually string theory has made essentially no progress in the last 20 years. You still can't calculate anything with it, it still doesn't make testable predictions, and there are still too many different versions of string theory, with no way to tell which (if any) is correct.

    A much better book is Lee Smolen's Three Roads to Quantum Gravity. What I like about it is that it focuses on basic principles of what a theory of quantum gravity must be like, rather than just describing all the (probably incorrect) details of one (probably incorrect) theory. Before reading Smolen's book, I'd also recommend starting off with QED: The Strange Theory of Light and Matter by Feynman, which describes the relatively well understood unification of quantum mechanics with special relativity (as opposed to general relativity).

    --
    Find free books.
    1. Re:book; better book by Curtman · · Score: 2, Interesting

      I don't think TV is a great media for exploring a subject, so much as it is great for presenting you with an overview of what something is about. I've tried many times to read physics books and tire of them pretty quickly because I don't understand some underlying principle. I need lots of pictures and naration to handle these concepts. Thanks for the suggested reading, I think this series will be enough of a snapshot to prompt me to pick one of these books up and actually get through it.

    2. Re:book; better book by Anonymous Coward · · Score: 0
      The thing that always bugs me about TV is that I can't turn the page when I want to, either forward or backward!

      After watching the show, I can say that forward is the only thing. They repeated the same ideas over and over and over. Sometimes they used the same sentance eight or nine times. Hokey special effects don't make up for that.

    3. Re:book; better book by MysticGlyph · · Score: 2, Interesting

      I also have read extensivly on the subject of string theory. I found the PBS program to be VERY helpful in laying out difficult to understand concepts and actually making things understandable to the laymen, or armchair (wannabe) physicist. Another great source for string theory information is at http//www.mkaku.org ...and Michio Kaku's book "Hyperspace" is a fun and informative read, I highly suggest it for anyone interested in learning more about string theory.

      --
      Try my new smokable Sig, ...Sig-erette.
    4. Re:book; better book by iansmith · · Score: 1

      "The thing that always bugs me about TV is that I can't turn the page when I want to, either forward or backward!"

      Get a TiVo, then you can! :-)

      Books have lots of great benifits, but a well done show (Like NOVA usually is) has advantages too.

      Use both.

  10. "equally accurate" by Bootsy+Collins · · Score: 1, Interesting

    It's unfortunate that the article describes GR and QM as being "equally accurate." Presumably that helps dramatize the conflict -- if they're equally accurate, there's no reason to decide whether one of them is a better approximation of reality than the other. That helps the "crisis," as they call it, seem more like a crisis.

    But in actuality, of our theories of the four forces, GR is the least well-tested of the four. It seems particularly inappropriate to compare the accuracy of predictions of GR to those of QM, since the predictions of QM have been tested to many more decimal places than those of GR (I think the theoretical prediction of the Lamb shift has been confirmed to something like 8 significant figures now). That's not indicative of a flaw in GR at all -- it merely reflects the fact that doing experimental/observational studies of gravity are really, really hard. But since GR hasn't been examined as well, we can't say that its predictions are equally accurate.

    1. Re:"equally accurate" by barawn · · Score: 2, Informative

      Er? QED is arguably the most accurate theory - something like what, 11 different measurements of alpha yield the same result to 10 digits or so? (I want to say that this is in Peskin & Schroeder's Quantum Field Theory, but I could be wrong). However, for one, that's only QED, not quantum mechanics in general. It's not like QCD is well tested - at all.

      And, for two, it depends on what you mean by "accurate". Certain portions of GR - for instance, the equivalence principle - have been tested ridiculously accurate - 1 part in 10^12, or something like that. Plus, if memory serves, the binary pulsar measurement was ridiculously good in agreement.

      QED is by far the more accurately tested theory of the two. By *far*. But if you group all quantum field theories together, then it's not so good (because strong strong interactions are just as hard as gravity), and "quantum field theories in general" start to look about as accurate as general relativity.

      I think the basic idea is that QM and GR are fundamentally different theories. You look at them, and it sounds like you're talking about two different Universes, with two different physical laws. And the problem is, that within the domain of their accuracy (GR is large-scale, 'strong' gravity, QFTs are generally short-range 'weak' interactions, but only because the long range stuff is classical) they're both extremely accurate - about as accurate as the measurement can make. And the main problem is that no one has a friggin' clue how to unify the two.

      Well, they have a clue. It's just that most of the time, that clue makes the universe look like a complete disaster. It's like in the 1930s, during the revolution in particle physics: "who ordered THAT?"

    2. Re:"equally accurate" by Bootsy+Collins · · Score: 1

      Oof.

      However, for one, that's only QED, not quantum mechanics in general. It's not like QCD is well tested - at all.

      Fair enough -- although, in the case of QCD, the reason for being poorly tested is the difficulty in extracting good predictions out of the theory (although the lattice gauge simulation folks have been promising much better ones for a long time now). The idea I was reaching for was that, to the extent that we currently extract testable predictions, QM was much better tested than GR.

      But then you reminded me that . . .

      Certain portions of GR - for instance, the equivalence principle - have been tested ridiculously accurate - 1 part in 10^12, or something like that. Plus, if memory serves, the binary pulsar measurement was ridiculously good in agreement.

      . . .which is embarassing because I really should have remembered the binary pulsar observations. I was thinking in terms of perihelion precession and all that stuff and completely forgot about that. Duh.

    3. Re:"equally accurate" by Anonymous Coward · · Score: 0

      you mean "accurate" or "precise".. If you are talking 8 vs. 10 decimals, then you mean precise.. We may never know what is "accurate" in most of these measurements.

    4. Re:"equally accurate" by barawn · · Score: 1

      He meant "accurate". Precision is the repeatability of the experiment, and the degree to which it varies. It's a flaw in the experiment, not in agreement with theory. When you're talking about an experiment agreeing with theory, you're talking about accuracy.

      As for the "accuracy" of the measurements, of course we know whether or not they're accurate. What you do is you take one constant ("alpha", the fine structure constant, in the case of QED) and let the experiment determine it, rather than it determining the experiment. Since the same theory explains all sorts of different predictions, the degree to which the experiments agree with each other on the value of "alpha" tells you how accurate your theory is.

      Currently, with QED, I think that's about 10 or 11 decimal places. (alpha is about 1/137, so that's about 9 orders of magnitude accuracy).

  11. I reserved Smolen's book... by Futurepower(R) · · Score: 1

    I thought the show was terrible. I reserved Smolen's book at the library. Thanks for the recommendation.

  12. Good thinking. Good recommendations. by Futurepower(R) · · Score: 1

    Mod parent up!!!! This is the most sensible comment I've found.

    1. Re:Good thinking. Good recommendations. by Anonymous Coward · · Score: 0

      Mod parent down!!!! It is Offtopic and an annoying "Mod parent up" post.

  13. Gravitation and it's source by BlankStare · · Score: 1

    Check out this link. I think these folks may be on to something: http://www.calphysics.org/gravitation.html

  14. I caught this show by chance by pmz · · Score: 1


    and have to say it was one of the best-digested shows about science I've seen in a very long time. This would be great stuff to show high-school-age students, as long as they are given a disclaimer: "this stuff is much harder than it looks, these guys on the show are Ph.D.s and have won Nobel Prizes..."

    --
    Healthcare article at Kuro5hin
  15. What has happened to Nova? by patniemeyer · · Score: 1

    Not withstanding this particular show - which sounds good - has anyone noticed that Nova just sucks now. I remember years ago that it covered interesting, deep topics in science in a way that no other show did. Now it's more in tune with the Discovery channel and recreating how Egyptians might have moved blocks of stone or other such nonesense.

    On that topic - is it possible to get *all* of the back episodes of Nova somehow? Are they in the public domain, being public television? I'm assuming not... sad.

    Thanks,
    Pat

  16. The Elegant Universe in an Nutshell by dexter+riley · · Score: 1

    I watched the first two hours last night, and here's what I got:

    1. General Relativity makes sense at large scales, and
    2. Quantum physics makes sense (if you're a Quantum physicist) at tiny scales. However,
    3. No theory has been proven to explain the universe at all scales. Luckily (for Brian Greene's publishers),
    4. The string theorists think they have! Also luckily (for the string theorists without tenure),
    5. There is no way to experimentally disprove String theory, so...
    6. ???
    7. Profit!!!
    8. Too bad Nova spent all the profit on digital effects of wiggling strings, and getting nobel laureates to talk on camera.

    Note that at very small times and/or scales, these steps may not appear in the order listed, and new rules may appear or vanish for no apparent reason.