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Are the foundations stable

  1. Sep 16, 2010 #1
    I enjoy Physics like many and always keep an eye out for new discoveries, but is our understanding of the universe becoming too complicated and involved.
    We are constantly finding new information that does not fit the current model, but by adding a new constant or variable into the equations it repairs the problem, but gives us new things to look for such as dark matter and dark energy.
    I can’t help thinking about Aristotle’s crystalline spheres and the Earth centered universe, this was a simple concept initially, until the motion of the planets was realised, then it became a complex mathematical model to try to explain this motion, Copernicus then simplified the problem, and removed the complexity.
    I hope we are not heading in that direction again, is the foundation sound, equations are build on previously established equations does anyone re-examine these? I want to see a unification theory, although it would be a shame if we have got it wrong again.
     
  2. jcsd
  3. Sep 16, 2010 #2
    And then Kepler brought complexity, which Newton simplified and then people looked more closely and things got complex again.

    The foundations are based on observations. Ultimately we have hundreds of years of data on how planets move, and so we try to describe what we see. It gets more difficult because as time passes, we get more and more data which people try to explain.

    I'm not sure that one exists. Reality is much too complicated.

    Also it's not getting it wrong. You are right to within some error.
     
  4. Sep 18, 2010 #3
    Dear Twofish-quant,

    "Reality is much too complicated" ???

    Sounds like a rationalization to me. Is that any way to instruct
    a newbee? Einstein would not say that, nor would Occam. The
    theory is (should be) quite simple...if "reality is too complicated"
    could it be that the theory is at fault and has become a
    "Rube Goldberg"(sp) machine?
     
  5. Sep 20, 2010 #4
    EnergyLoop, I've been thinking of entering a post virtually identical to yours, thank you for sparing me the trouble! I'm also a fan of physics, even signed up for physics, switched to mechanical engineering when I learned that my math talent was not all that strong plus that more years of college are needed to get anywhere in physics.

    I, for one, am getting a bit fed up with the apparent ease that physicists can drag up just about anything to make their numbers come out right, e.g., dark energy. Problem is, I want to trust physicists, and feel uncomfortable when it seems like they are faking it.

    Anyway, thanks, EnergyLoop!
     
  6. Sep 27, 2010 #5
    It's an observation.

    Let's suppose you look at a distant star. It's just a point of light and points of light are simple. Now suppose you look closer, and you find that it's not just a point of light, there are magnetic fields, mass loss, and all sorts of complex things. Now it may have planets, and on one of those planets, it may have intelligent beings with complex societies.

    So the more you see, the more complex things are. We are really seeing this sort of thing with cosmology.

    Yes. It is.

    Einstein was wrong about a great many things. So was Occam. Coming up with a simple theory that explains everything is great if you can do it, but it turns out that you can't. Once you've been in the business long enough, you give up trying to explain everything and you are doing good if you can find a simple theory that explains *anything*.
     
  7. Sep 27, 2010 #6
    So Einstein and Occam can join the club. I really like that.
    I had suspected that Einstein still had a pretty tight grip
    on expert opinions. And I'm always bringing up Occam
    when things get too complicated. Think I'm tending
    a little more toward Murphy. But I'm still wondering
    whether a simple theory can sprout many details that
    only make it seem to be complicated.
     
  8. Sep 27, 2010 #7
    If you go the opposite direction of cosmology, you'll find an interesting progression and conundrum.

    Very complex phenomena which we cannot predict reliably like weather come from emergent behavior of molecules that are relatively simple. The major interactions of molecules are well understood as they relate to our atmosphere. If you go one level smaller, you find things are even simpler, we have basically only three components for everything: the electron, the proton, and the neutron.

    So as we go smaller we get fewer less complex concepts. Part of the reason, is that one force, electromagnetism dominates at the small scale because of the proximity of the particles and the relative strengths of the forces.

    Nature creates complexity through emergence when you go in the opposite direction from smaller to larger. Cosmology represents even greater complexity because tiny forces result in major effects. This is much like how the tiny Coriolis Effect causes the rotation of low-pressure cyclones to rotate in counter-clockwise direction in the Norther hemisphere and clockwise in the Southern Hemisphere.

    The conundrum is that when physicists were searching for smaller and smaller particles, they found electrons, and protons and neutrons and things appeared to be simpler. Then they started getting an explosion of different types of new particles as they smashed atoms together at higher and higher energies in particle accelerators. This was not expected. This has been cleaned up a bit with the Standard Model's 12 different types of fermions and bosons but the situation is not as simple as the direction of prior research would have led scientists to believe, i.e. simpler and simpler leads, at the limit, to one single thing.

    String Theory purports to solve this dilemna by proposing that all the particles are, in turn, composed of one single thing: strings vibrating at different frequencies.

    Personally, I think there are elements of String Theory that are the right approach, but I don't find the theory to be at all a simplification. I mean, String Theorists will be the first to tell you that no one knows what String Theory even is at this point. It must be pretty complex for that to be the case after almost 40 years of research.

    I'm still hoping for a simple theory that one could explain to those without Ph.Ds in mathematics. There are plenty of indications that all of our current theories are not the last word (but then they never have been), not the least of which is the inability to merge general relativity with quantum mechanics.
     
    Last edited: Sep 27, 2010
  9. Sep 27, 2010 #8
    That the atom is a merging to an electronprotonneutron entity (force?)?

    I'm not clear about that Coriolis effect. It looks like a real force
    to me and that rotation(spin) therefore appears to be a fifth force.
    IE, could(should) spin be a fifth force? Or is it just the result
    of spinning relativity?

    Then is it old style thinking that the 4 forces could(should) be be
    merged into a single force? That the success of electroweak merging and
    strongelectroweak merging(standard model) could(should) lead to a single
    strongelectroweakgravity merging? If we could(should) quantize
    gravity?

    Strings? What's that all about? Don't answer unless it's simple; I suspect
    it's volumes.

    It is my intuitive(full of holes) feeling that theories should
    make predictions. And that if a theory cannot predict, that it
    is only a conjecture. I am being told(here on PF), that our
    observations predict a void(dead) universe in the distant
    future. Should not a theory be reserved to make this prediction,
    not merely observations? IE, that data leads to conjecture,
    not prediction? I must admit that I have no personal theory on
    this matter; I just feel that we don't even have a theory. And
    all we have is really just a filing cabinet of observations; that
    the theory is only on how the filing cabinet is arranged(General
    Relativity).
     
  10. Sep 28, 2010 #9
    @ ClamShell (That the atom is a merging to an electronprotonneutron entity (force?)?)

    ''In physics, fundamental interactions (sometimes called interactive forces) are the ways that the simplest particles in the universe interact with one another. An interaction is fundamental when it cannot be described in terms of other interactions.''

    http://en.wikipedia.org/wiki/Gravitation
    http://en.wikipedia.org/wiki/Particle_physics
    http://en.wikipedia.org/wiki/Atom
    http://en.wikipedia.org/wiki/Fundamental_interaction
    http://en.wikipedia.org/wiki/String_theory


    http://en.wikipedia.org/wiki/Coriolis_effect
     
  11. Sep 28, 2010 #10
    I don't think String Theory seeks to simplify, but to explain... in a way, if it really is what it's supposed to be then it might be the proverbial safe with the key locked inside.
     
  12. Sep 29, 2010 #11

    From Wikipedia link above:

    "String theory is a developing theory in particle physics that attempts to reconcile quantum mechanics and general relativity.[1] It is a candidate for the theory of everything (TOE), a manner of describing the known fundamental forces and matter in a mathematically complete system. The theory has yet to make quantitative experimental predictions, which a theory must do in order to be confirmed or falsified."

    I have been told that a theory has two parts: the formalism and
    the interpretation. And that the interpretation is not only required
    to faithfully reproduce observations, but is also required to
    make predictions that can lead to sensitive experiments that
    will either confirm or deny the validity of the theory. This leads
    me to believe that String theory is only the formal part. If
    it is based on the concept of a *vibrating string*, it is a simple
    formalism. The interpretation seems to be the hard part.
     
  13. Sep 29, 2010 #12
    There is no formalism of string theory... there aren't even exact equations yet. Nearly everything you've said is strangely off-base.
     
  14. Sep 29, 2010 #13
    What I said was:

    I have been told that a theory has two parts: the formalism and
    the interpretation. And that the interpretation is not only required
    to faithfully reproduce observations, but is also required to
    make predictions that can lead to sensitive experiments that
    will either confirm or deny the validity of the theory. This leads
    me to believe that String theory is only the formal part. If
    it is based on the concept of a *vibrating string*, it is a simple
    formalism. The interpretation seems to be the hard part.

    Knew I should have put a question mark in there. I will learn
    only if you correct me. But right now, I don't even know
    what (if anything) that I said that was not off base.
     
  15. Sep 29, 2010 #14
    From Wikipedia link above:

    Although string theory comes from physics, some say that string theory's current untestable status means that it should be classified as more of a mathematical framework for building models as opposed to a physical theory.[31] Some go further, and say that string theory as a theory of everything is a failure.[32][33] This led to a public debate in 2007,[34][35] with one journalist expressing this opinion:

    "For more than a generation, physicists have been chasing a will-o’-the-wisp called string theory. The beginning of this chase marked the end of what had been three-quarters of a century of progress. Dozens of string-theory conferences have been held, hundreds of new Ph.D.s have been minted, and thousands of papers have been written. Yet, for all this activity, not a single new testable prediction has been made, not a single theoretical puzzle has been solved. In fact, there is no theory so far—just a set of hunches and calculations suggesting that a theory might exist. And, even if it does, this theory will come in such a bewildering number of versions that it will be of no practical use: a Theory of Nothing."
    —Jim Holt[36]"

    Therefore, I think that the answer to the question posed by by this thread is: No
     
  16. Sep 29, 2010 #15
    I don't think you do. What I think is really happening is that people ignore the complex things. No one really understands how an atomic nucleus works, and no one understands how a proton works.

    Not true. At small scales, the strong nuclear force dominates and the strong nuclear force is extremely companies because it is strong. Electromagnetism is relatively weak so that you can look at two EM interactions separately. This doesn't work with strong nuclear forces.

    Also even with EM, you can get chaotic behavior in atoms.

    I don't think this is true.
     
  17. Sep 29, 2010 #16
    It should be pointed out that one of the more promising approaches that I've seen to quantize gravity (loop quantum gravity) is a fundamentally different approach. Rather than trying to come up with a "theory of everything" they just quantize gravity and ignore the other forces.

    It's not too difficult to come up with a string theory that explains many things. If you have *only* classical gravity and EM, then it's easy to come up with a theory that explains that. It's when you try to explain *everything* that things become hard, and I like some of the recent ideas in quantum gravity because they just try to explain gravity.

    Also there is no need for the theory to produce *correct* predictions. Theories that produce bad predictions that are obviously wrong can be extremely useful. The problem that I have with string theory, is that it hasn't gotten to the point that it can make *BAD* predictions.

    The point that the purpose of a model is to produce *bad* predictions is something that non-scientists don't get. The nice thing about the standard model of cosmology is that it makes predictions. The standard model of cosmology-2010 can and does produce some *BAD* predictions, and dealing with those predictions will get us to standard model-2020.
     
  18. Sep 29, 2010 #17
    Except that vibrating strings are not simple at all.
     
  19. Sep 29, 2010 #18
    Makes sense, or should I say: Makes sense to my sense of order; thanks
     
  20. Sep 29, 2010 #19
    Not simple and not formalized... I don't think ClamShell actually understands however.

    ClamShell: Do some reading on the formalism of QM, then try to find an analog in String Theory... you won't.

    Twofish-Quant: The point about Bad Predictions... String Theory is definitely weak as hell; the scales needed cannot be probed, it doesn't make unique predictions that have been tested, and it doesn't make predictions that can be falsified... it's either very young, or complete rubbish. Lets face it, the only reason it's being taken at all seriously is that when it comes to unifying 4 forces, it's the only game in town. As you point out the approaches which seek to focus on quantizing gravity without unification are possibly far more useful for now.
     
  21. Sep 29, 2010 #20
    Clearly, going from 94 (naturally occurring) elements to 3 basic atomic building blocks is a simplification. Further, the number of ways that the elements can interact is vastly more complex than the number of ways that the proton, neutron, and electron can interact. A simple chart of the nuclides shows an exhaustive list of the possible interactions for the subatomic particles. We are building new molecular compounds and discovering ones in nature each and every day.

    I thought I pointed out that things started to get more complex only once people started looking at the subatomic particles more closely.

    I should have been more precise. My comment referred to the scale up to but not including the subatomic particles. Once you consider the strong force, obviously it's called strong for a reason and it dominates in its regime at the nucleus and within protons and neutrons. But it only dominates once you get to the scale of the nucleus, for atomic interactions and above, it has negligible effect.

    My point was that we saw a nice conceptual progression from more types of parts with greater complexity to less types of parts with lesser complexity, until we started looking at the nucleus more closely. What the physicists found when they starting probing the nucleus and subatomic particles further was a big surprise.

    And, as you point out, we still don't understand the nucleus or the proton, despite so many's adoration of the Standard Model. For example, we don't have a good formula for computing the binding energies of the nucleus. The best one we have is part theory and part empirical fudge factors and it differs significantly from actual experimental measurement for many specific nuclides. Compared with the precision that we can judge planetary movement this is pitiful.

    I said:
    You said:
    Weather, life, stars, galaxies, molecules, etc. are all much more complex than their constituent parts. In what way do you think my statement was not true? Do you not think that a simple biological compound like DNA is more complex than its constituent parts? A human brain?

    Or is it that you don't think that these complex phenomena are emergent?
     
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