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Thread: Why is the Big Bang Theory better than Steady State?

  1. #201  
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    Quote Originally Posted by kojax View Post
    I compare Ptolemy's geocentric solar system against Copernicus' heliocentric one. The first thing to note is that:

    1) - Ptolemy's system matched observation better than Copernicus' system. {snip}
    That's exactly right. For a great many purposes, the Ptolemaic model was a perfectly fine model. Its undoing wasn't the appearance of the heliocentric model per se, it was the steady accumulation of observational evidence that required ever-more elaborate and ad hoc corrections to bring the Ptolemaic model into agreement, and the ability of the heliocentric model to make ever better predictions once Newton's law of gravitation began to be applied.

    So if we are to continue with your historical analogy, SST is similar to the Ptolemaic one, where limited observational evidence initially allowed survival for a time as a contender. Once Slipher, Hubble et al. got into the story, though, the SST model began to look less viable. After precise CMB surveys were performed, the SST model was essentially consigned to the scrap heap of history. And again, multiple, independent lines of evidence and theory all converge to support the BBT model.

    If Steady State ever does reach completion and turn out a workable model for us, it will almost certainly bring physical laws of its own as well, and explanations that let us use those laws to do something useful.
    Yes, and if pink unicorns were bad-smelling flowers, then politics would be cathodes.

    I would argue that SS models have in fact already reached their completion. The end state is one of failure after many valiant attempts.

    The main problem with the BBT is that, like Ptolemy's system, expansion is wholly unexplained and quite capricious. You can't make a law about expansion in the BBT because it doesn't follow any kind of a reliable pattern in its behavior.
    I have no idea what you mean above. However, you appear to be imposing your own personal tastes on nature. The universe is under no obligation to be pleasing to your sense of aesthetics, so the universe's failure to conform to the emotional needs of humans is irrelevant. "The universe is not about you."

    The earliest stages of BBT are immune to observation
    as are the "earliest stages" of SST.

    , and so we have to rely 100% on application of known laws to describe them. That makes it a one way street as far as knowledge. If our known laws change, the BBT will be changed by them. But a better understanding of the BBT is not likely change our known laws. (At least not the early stages.)
    I would state things differently. As with any good scientific theory, BBT has been shaped by observational evidence. Consider this: Incredible energies are, and have been, at play in the universe. These energies are vastly greater than anything we can imagine harnessing in a terrestrial laboratory. Science progresses at the edges, and the edges are out there, not here. I see no reason why the process of shaping BBT to accommodate new understandings of the laws of nature shouldn't continue.
    Last edited by tk421; July 27th, 2012 at 10:17 AM.
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  2. #202  
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    Quote Originally Posted by tk421 View Post
    Quote Originally Posted by kojax View Post
    I compare Ptolemy's geocentric solar system against Copernicus' heliocentric one. The first thing to note is that:

    1) - Ptolemy's system matched observation better than Copernicus' system. {snip}
    That's exactly right. For a great many purposes, the Ptolemaic model was a perfectly fine model. Its undoing wasn't the appearance of the heliocentric model per se, it was the steady accumulation of observational evidence that required ever-more elaborate and ad hoc corrections to bring the Ptolemaic model into agreement, and the ability of the heliocentric model to make ever better predictions once Newton's law of gravitation began to be applied.

    So if we are to continue with your historical analogy, SST is similar to the Ptolemaic one, where limited observational evidence initially allowed survival for a time as a contender. Once Slipher, Hubble et al. got into the story, though, the SST model began to look less viable. After precise CMB surveys were performed, the SST model was essentially consigned to the scrap heap of history. And again, multiple, independent lines of evidence and theory all converge to support the BBT model.
    The heliocentric solar system suffered that same fate. It proposed circles, and observation accumulated until it became apparent that circular orbits didn't exist. Then the model failed. It failed utterly, and was rejected. Later on, someone decided to pick it up out of the trash bin and make a change to it, and see if it might stand up to scrutiny in its changed form. He was fortunate and it did.

    The problem with blind, near-bureaucratic, meticulous adherence to evidence and only evidence, un-tempered by any sense of aesthetics, is it renders us unable to see any patterns that aren't obviously apparent at first glance. We're lucky Kepler was willing to run himself ragged trying to find the hidden pattern behind it all. It was blind faith in aesthetics. He believed that the universe would follow an elegant pattern, and just kept looking until he found one. He only got Brahe's notes over his dead body (literally).

    I would suggest that the pattern of past scientific discovery, is that despite any and all first appearances, the universe has always turned out to be elegant in the past. It will probably continue turning out to be elegant in the future.

    The main problem with the BBT is that, like Ptolemy's system, expansion is wholly unexplained and quite capricious. You can't make a law about expansion in the BBT because it doesn't follow any kind of a reliable pattern in its behavior.
    I have no idea what you mean above. However, you appear to be imposing your own personal tastes on nature. The universe is under no obligation to be pleasing to your sense of aesthetics, so the universe's failure to conform to the emotional needs of humans is irrelevant. "The universe is not about you."
    It's not a matter that the universe has any kind of "obligation" to do so, but accumulated past experience in the history of science tells us that it most likely will do so.

    As with many things, there are patterns within patterns. For example, an object may be both moving and accelerating. Looking at its velocity, you would expect it to keep moving and may predict it will go a distance equal to . But if you do so you're ignoring the bigger pattern of acceleration.

    It's not that different here. There is an overarching pattern to the progress of science. This pattern has born out throughout its past, but you're only looking at one moment.


    The earliest stages of BBT are immune to observation
    as are the "earliest stages" of SST.
    There is no "earliest stage" of SST. That's why it's called "Steady State".

    The whole point of the theory is to propose that no point in the universe's history has ever been fundamentally different from the present.
    Some clocks are only right twice a day, but they are still right when they are right.
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  3. #203  
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    Quote Originally Posted by kojax View Post
    The heliocentric solar system suffered that same fate. It proposed circles, and observation accumulated until it became apparent that circular orbits didn't exist. Then the model failed. It failed utterly, and was rejected. Later on, someone decided to pick it up out of the trash bin and make a change to it, and see if it might stand up to scrutiny in its changed form. He was fortunate and it did.
    Before Newton, there was no theoretical framework -- other than religious ones. Hence, there were only the loosest of constraints on possible models. And within the observational dataset of the time, the Ptolemaic, Tychonic and Copernican models could all compete fairly well. Even Kepler's nested-polyhedra model could be force-fit, after a fashion. All could be called useful models within specified error bars, for a suitably constrained subset of the solar system.

    But today things are quite different in several important respects that you can't ignore (well, I guess you can, because you seemingly do; perhaps I should say that one ought not ignore them). One is that we now have an elaborate theoretical framework (actually overlapping sets of frameworks), informed by an incredibly rich dataset generated not only from astronomical observations, but also from particle physics, so the data span a breathtaking number of orders of magnitude. The constraints are enormously tougher, not looser. You seem insufficiently appreciative of the magnitude of the support for the BBT, and the magnitude of the falsifying evidence against SST.

    The problem with blind, near-bureaucratic, meticulous adherence to evidence and only evidence, un-tempered by any sense of aesthetics, is it renders us unable to see any patterns that aren't obviously apparent at first glance.
    The situation with aesthetics is that, being essentially psychological, different humans will have different notions of what is aesthetic, so there won't be uniform agreement on what constitutes an aesthetically satisfying theory. It's certainly turned out to be a very unreliable guide to the generation of good theories (here "good" means that it generates predictions in accord with experiment). Cosmological literature is rife with elegant theories that are wrong. So the hard-learned lesson is "aesthetics is nice, but don't get too attached to it as a goal in physics."

    I'm not sure what you mean by "blind adherence to evidence." A scientific theory certainly must reproduce in its predictions what experimental evidence shows to be reality. I don't know if or why you would call that blind; I would call it enlightened because it's this constraint that allows the triumph of reality over fantasy. That is the revolutionary, subversive aspect of the scientific method. It doesn't matter how elegant your idea is, nor how powerful or well-published you are -- if evidence says your theory doesn't work, it doesn't work.

    We're lucky Kepler was willing to run himself ragged trying to find the hidden pattern behind it all. It was blind faith in aesthetics. He believed that the universe would follow an elegant pattern, and just kept looking until he found one. He only got Brahe's notes over his dead body (literally).
    I would reword your narrative this way: We're lucky that Kepler believed that there is order to the workings of the universe. By believing that the universe conforms to certain laws, he worked to collect the data that would reveal those laws, setting the stage for Newton.

    That's exactly how science works, kojax. You seem to believe that Kepler did something beyond what scientists do daily, but what you call his "aesthetics" was just a proxy for "laws of nature" or some similar thing.

    I would suggest that the pattern of past scientific discovery, is that despite any and all first appearances, the universe has always turned out to be elegant in the past. It will probably continue turning out to be elegant in the future.
    Since, de gustibus non disputandum est, I can't agree or disagree. I happen to find many aspects of quantum theory inelegant, for example, and certainly found it more so when I was first introduced to it as an undergrad. As pointed out by a grad TA when I expressed that sentiment, he pointed out that our aesthetic sense is the result of evolutionary selection pressures, including the imperative to reproduce. Nowhere in that description is found a direct acknowledgment of quantum phenomena, so should it be surprising that human brains that are tuned to find food and mates don't see quantum elegance right away, if ever? But shouldn't a theory that can predict experimental outcomes to umpteen decimal places get some credit for beauty? So, by all means be guided by an aesthetic sense, but don't apply it too narrowly.

    There is no "earliest stage" of SST. That's why it's called "Steady State"

    The whole point of the theory is to propose that no point in the universe's history has ever been fundamentally different from the present.
    You rather missed the quotation marks around "earliest stage." It was deliberately rendered that way to trigger a cognitive pause, with the following purpose: To prove observationally that the universe is a steady-state one, you'd need to look infinitely backward in time and always see the same thing. Just as the BBT has an observational limitation (we can't see farther back than the time of last scattering), so does the SST. In that sense, the SST may be functionally unfalsifiable. If so, it could then be argued that SST is actually an unscientific theory, of the same level as a religious narrative.
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  4. #204  
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    Quote Originally Posted by tk421 View Post
    Quote Originally Posted by kojax View Post
    The heliocentric solar system suffered that same fate. It proposed circles, and observation accumulated until it became apparent that circular orbits didn't exist. Then the model failed. It failed utterly, and was rejected. Later on, someone decided to pick it up out of the trash bin and make a change to it, and see if it might stand up to scrutiny in its changed form. He was fortunate and it did.
    Before Newton, there was no theoretical framework -- other than religious ones. Hence, there were only the loosest of constraints on possible models. And within the observational dataset of the time, the Ptolemaic, Tychonic and Copernican models could all compete fairly well. Even Kepler's nested-polyhedra model could be force-fit, after a fashion. All could be called useful models within specified error bars, for a suitably constrained subset of the solar system.

    But today things are quite different in several important respects that you can't ignore (well, I guess you can, because you seemingly do; perhaps I should say that one ought not ignore them). One is that we now have an elaborate theoretical framework (actually overlapping sets of frameworks), informed by an incredibly rich dataset generated not only from astronomical observations, but also from particle physics, so the data span a breathtaking number of orders of magnitude. The constraints are enormously tougher, not looser. You seem insufficiently appreciative of the magnitude of the support for the BBT, and the magnitude of the falsifying evidence against SST.
    I don't think the data is going to be wrong. I see what you're saying about it being highly constrained, but patterns crossing disciplines is not uncommon in science. I understand, for example, that James Clerk Maxwell got a lot of the math for his equations from the existing equations of fluid dynamics. Electricity isn't exactly a fluid, but it could be described by the same patterns.

    As I read more about it, it appears that black body equations come from extrapolating the equations for harmonic resonance, and adding in the effect of photons quantizing it. You don't think that any other phenomena governed by the same principle or a similar principle might be discovered to exist? Even if we go with the BBT, we still have to allow a new phenomena to exist in expansion itself. If expansion exists the way the BBT proposes, then there are no rules to describe it. If two phenomena exist, SST's expansion, and one to create the BBT, then rules exist to describe both phenomena.

    So the question is: do you want one unconstrained phenomenon? Or two constrained phenomena?




    We're lucky Kepler was willing to run himself ragged trying to find the hidden pattern behind it all. It was blind faith in aesthetics. He believed that the universe would follow an elegant pattern, and just kept looking until he found one. He only got Brahe's notes over his dead body (literally).
    I would reword your narrative this way: We're lucky that Kepler believed that there is order to the workings of the universe. By believing that the universe conforms to certain laws, he worked to collect the data that would reveal those laws, setting the stage for Newton.

    That's exactly how science works, kojax. You seem to believe that Kepler did something beyond what scientists do daily, but what you call his "aesthetics" was just a proxy for "laws of nature" or some similar thing.
    I think we agree on this so far. Do you understand that really what I am wanting to do is find order? By believing that expansion conforms to certain laws, and then trying to find them, I don't believe it's that much different from what Kepler did.

    SST may prove to be that law or it may not, but one cannot expect to arrive at their goal always on the first try. The BBT provides no laws about expansion.


    I would suggest that the pattern of past scientific discovery, is that despite any and all first appearances, the universe has always turned out to be elegant in the past. It will probably continue turning out to be elegant in the future.
    Since, de gustibus non disputandum est, I can't agree or disagree. I happen to find many aspects of quantum theory inelegant, for example, and certainly found it more so when I was first introduced to it as an undergrad. As pointed out by a grad TA when I expressed that sentiment, he pointed out that our aesthetic sense is the result of evolutionary selection pressures, including the imperative to reproduce. Nowhere in that description is found a direct acknowledgment of quantum phenomena, so should it be surprising that human brains that are tuned to find food and mates don't see quantum elegance right away, if ever? But shouldn't a theory that can predict experimental outcomes to umpteen decimal places get some credit for beauty? So, by all means be guided by an aesthetic sense, but don't apply it too narrowly.
    A purely iterative theory could also yield perfect predictions. You know, like one where case by case, you just have a list miles long of cases and results, and each one matches observation because we simply wait until we've seen something before we write it down. That's what I mean by "purely bureaucratic" adherence to observation. So long as you tabulate the data accurately, you're guaranteed to arrive at some theory. Probably not the best one, but you'll get one.


    As to human perception of aesthetic beauty, one must remember that "natural selection" means the environment is essentially writing your DNA. Part of that environment is the universe it finds itself in. But also I see your point. We didn't evolve to be able to live in a vacuum, even though almost all of space is vacuum. So there's no reason to think we would evolve with other necessary adaptations to space, like an innate understanding of it.


    There is no "earliest stage" of SST. That's why it's called "Steady State"

    The whole point of the theory is to propose that no point in the universe's history has ever been fundamentally different from the present.
    You rather missed the quotation marks around "earliest stage." It was deliberately rendered that way to trigger a cognitive pause, with the following purpose: To prove observationally that the universe is a steady-state one, you'd need to look infinitely backward in time and always see the same thing. Just as the BBT has an observational limitation (we can't see farther back than the time of last scattering), so does the SST. In that sense, the SST may be functionally unfalsifiable. If so, it could then be argued that SST is actually an unscientific theory, of the same level as a religious narrative.
    Both have the Hubble Sphere, too. The CMBR provides a nice exception to that problem because it would have been emitted from everywhere at once.

    Another source we might hope to find would be something that has been incredibly cold for a very long time, of for some other reason hasn't undergone much change. If we could still reliably date it, then we might get something out of that.
    Some clocks are only right twice a day, but they are still right when they are right.
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