<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It is very simple. A theory is set of principles that produces a predictive model, almost always a mathematical model,</DIV></p><p>Alright, but there must be a greater requirement. Otherwise, someone can simply whip up a math formula about how many elves can fit on the head of a pin, and "predict" any number. A mathematical number about "inflation" isn't particularly compelling to a "skeptic" of the existence of "inflation". How does one know such a thing even exists in nature? </p><p>The "predictions" of many of these arguments have also changed over time, They will change again and they will be modified to "explain" the recently discovered "dark currents" flowing through our universe. </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>the predictions of which have been verified by a large body of empirical evidence.</DIV></p><p>Without a control mechanism and without a clear way to "falsify' a particular "theory" (Lambda-CDM theory for instance), what exactly do you mean by the term "emprical evidence"? Got any emprical evidence of MOND theory, or any particular evidence of a particular hypothetical SUSY partical you find compelling? If so, why? What exactly constitutes "emprical evidence' unless a control mechanism is being applied to a real "experiment"? What empircal experiment (complete with control mechanisms) demonstrates that "inflation" has some affect on objects in nature? Where does "inflation" come from?</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>That empirical evidence can be in the form of laboratory experiments</DIV></p><p>Here we seem to be in total agreement. I have no problem with Birkeland's work with aurora because they were "lab tested" ideas, not simply math formulas on paper.</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>or it can be in the form of precision measurements of phenomena observed in nature. </DIV></p><p>Well, there's a problem here without a control mechanism from a skeptics perspective. I might "observe" something that leads me to believe that distant objects are "accelerating'. Chalking that up to "dark" forces means nothing if the force itself has not been identified. Slapping math formulas to a placeholder term for human ignorance does nothing constructive for us without identifying the actual force of nature that is responsible for this observation.</p><p>Birkeland didn't just point to the aurora and claim that "dark energy" cause that phenomenon. He created actual empirical experiments to test "real" and "known" forces of nature. He "tested" his ideas in physical experiments and made careful observations as he made changes to his control mechanisms. He left nothing to chance. </p><p>Whereas Chapman's theories looked fine on paper and might have been computer modelled with great precision, the failed to match the energy flow of particles in our atmosphere. Birkeland's model was superior because he paid attention to detail, took in-situ measurements, created emprical experiments *and* he did the math. Math alone did not make his theory superior to Chapman's theories. His empirical experiments and in situ measurements made his theory superior to Chapman's ideas. Whereas Birkeland's theories on energy flow stood the test of time, Chapman's math formulas were eventually laid to rest. They "predicted" the right amount of energy, but not the actual flow pattern of those energy flows. </p><p>IMO Birkeland's "methods" are "classic" methods of science. He built real experiments, varied the control mechanisms of his experiments and took maticulous notes. He took in-situ measurements of the magnetic fields of the planet during solar storms. He did it "by the book". IMO that's why his work has stood the test of time, or most of it anyway. We have learned a few things about our universe since that time, but the basic concepts of energy flow patterns that Birkeland produced in his lab have certainly stood the test of time and have fit with recent "observations", that Birkeland himself could not have accessed in his time. </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The key element is predictive capability that is in agreement with experimental data.</DIV></p><p>I don't seem to have a problem with that logic as long as one sticks to *known and identified* forces of nature. When astronomers start labeling forces of nature, "dark this" or "dark that", I fail to comprehend the value of putting math to these items. They do not exist in nature unless you can demonstrate that they do exist in nature. A "dark force" tells me nothing. A physical experiment tells me how it works. </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Predictive capability in physics is accomplished by means of mathematical models that allow the basic principles of the theory to be applied to a wide variety of situations. </DIV></p><p>The problem from a skeptics viewpoint is that these theories have become a little *too* easy to manipulate and make to fit an endless variety of various possible situations. Inflation for instance has 'evolved' over time, as have the various "properties' being assigned to "dark matter". I've now seen articles talking about the half life of 'dark matter', it's abiliity to "pass through' other forms of matter, it's ability to emit gamma rays, and most recently it's ability to release hundred billion volt electrons. I've yet to see anyone produce a gram of this stuff to verify any of these presumed "properties" of "dark matter" and yet I'm told it's many times more abundant than the dirt in my backyard. I must say, this sounds "fishy" at some point. How many "properties" are we allowed to ascribe to an unverified entitiy and how many mathematical "predictions" are we allowed to make *without* ever "testing" the ideas?</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>This requires that acceptable theories be quantitative rather than qualitative and descriptive in nature.</DIV></p><p>Here's the rub as I see it. As a skeptic of current theory, I don't have any trouble with the quantification part of what's going on in astronomy. It seem adequately quantified, in fact it seems overly fixated on quantification, and it's lacking in "qualification". Birkeland didn't take Chapman's "mathematical only" approach to energy exchanges between spheres in space. He built actual experiments to test his ideas using real parameters that might be found in space. He build a sphere in a vacuum and simulated his theories in actual emprical experiments and created aurora around his spheres as he "predicted". There's a "qualification" aspect here that seems to be completely lacking in contemporary theories of astronomy. </p><p>It's find to "assign" properties to something you call "inflation", but when do I get to see it work in laboratory experiment with control mechanisms? Am I simply supposed to accept this on faith, or is there a physical force of nature called "inflation" that can be demonstrated to exist in nature? </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It also imposes a requirement for rigorous formulation of the conditions under which the theory applies and the parameters that can be used to describe and predict natural phenomena. </DIV></p><p>But the "properties" being ascribed to various theories has exceeded what is "natural", at least what "naturally" shows up in emprical experimentation. Dark matter is now being presumed to emit billion volt electrons, gamma rays, etc, yet it's never been done in a lab. Inflation is presumed to have increased volume over many orders of magnitude yet retained a near constant density. The "properties" being assigned to these "forces" are beyond 'natural", some of them are "supernatural". No other known force of nature behaves this way as it relates to density and volume.</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Quantitative descriptions are required, rather than descriptive analogies.</DIV></p><p>Fine, but that alone isn't enough to always distinguish between competing theories. Prior to recent lensing data, MOND theory was indistinguishable from "dark matter" theories as it related to "predicting" the galactic rotation patterns of galaxies. Chapman's math formulas were "practical" and useful at "predicting" the total amount of energy exchange between the sun and the Earth, but they failed to accurately predict the flow patterns of energy. Do we have to wait 70 years to verify one theory over another, like Birkeland's theory or Chapman's theory only due to a lack of information, or is there something useful in Birkeland's classic "approach" that can be applied here and now to most scenarios we might find in space? </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>When a theory produces predictions that are contradicted by valid experimental data, it is wrong. </DIV></p><p>In my experience that is rarely if ever true. I'll bet there are still a few MOND theorists who are attempting to make some mathematical sense out of the more recent lensing data. I'm sure that inflation theory didn't crumble when we found "holes" in WMAP data, and it will be modified again to "predict" those "dark flows" somehow. I've noticed that astronomers rarely if ever just "give up" on a theory simply because it failed to predict a specific observation.</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It may continue to be considered a valid approximation under some circumstances, as for instance Newtonian mechanics is considered a valid method of analyzing the movement of bodies when velocities are small when compared to the speed of light and gravitational fields are modest.</DIV></p><p>I hear you, but... </p><p>For that matter, Chapman's theories still mathematically "predict" the correct overall amount of energy exchange, but his theories fail to tell us anything about our universe or how it really functions. Birkeland's model was "better" and more accurate. Why? Can we apply his "method' here to other types of 'observations"?</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>When applied at the scale of astronomy, theories such as general relativity enjoy broad applicability on the basis of their validation via precise observations of natural phenomena and their predictive capability.</DIV></p><p>Ok. Einstein's "predictions" have been veried to tell us more about the natural universe than Newton's simple concepts. </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So for instance general relativity enjoys acceptance due to a broad range of observations and its predictions are generally accepted unless directly contradicted by experiment or conflict with equally well-established theories (as for instance is the case near the singularity of a black hole where the conflict with quantum mechanics shows that general relativity may not be a valid approximation).
http://en.wikipedia.org/wiki/General_relativity <br /> Posted by DrRocket</DIV></p><p>Yet Einstein himself didn't believe in "black holes" to begin with.
</p><p>There's another issue here that comes into play from a historical perspective. Einstein's simplified GR theories have an effect on material objects that in no way resembles the behaviors and movements of matter in Lambda-CMD theory. So many different and unique "sub-hypothesis" have been stuffed into Einstein's early GR theories that gravity no longer has the same meaning in these formulas. </p> <div class="Discussion_UserSignature">
It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>