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WIMPs AWOL Again?
In article , "Robert L.
Oldershaw" writes: It depends on the theory, Robert. -------------------------------------------------------------------------------------------- So, the bottom line is that you cannot make a definitive prediction regarding the galactic dark matter. The whole idea of science is that different theories make different predictions which can be used to distinguish them. You seem to think that having more than one theory is a bad idea (and thus don't see the need for observations). |
#12
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WIMPs AWOL Again?
Robert L. Oldershaw wrote:
That's how things have been going for decades, except that nothing actually gets excluded, just "adjusted". Strings, branes, WIMPs, SUSY, extra dimensions, and so on, have been around for decades and are "adjusted" in an ad hoc manner when observations or theoretical constraints do not support them. Has anything been "exluded"? I have to say I'm no expert on these theories, but it seems to me that adapting theories in light of new evidence is science, as long as there is still room to do so within previously existing constraints. In that case, there is not enough data to exclude the theory. If future research were to reveal that the existance of WIMPS 27 GeV would necessarily cause some observable effect, and that effect is never observed, then it would be possible to exclude the theory. It is only holding on to unmodified theories by ignoring inconvenient data that would be a problem. |
#13
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WIMPs AWOL Again?
On Aug 21, 4:26*am, Phillip Helbig---undress to reply
wrote: In article , "Robert L. Oldershaw" writes: It depends on the theory, Robert. ---------------------------------------------------------------------------*----------------- So, the bottom line is that you cannot make a definitive prediction regarding the galactic dark matter. The whole idea of science is that different theories make different predictions which can be used to distinguish them. *You seem to think that having more than one theory is a bad idea (and thus don't see the need for observations). ------------------------------------------------------------------------ Your two posts are somewhat contradictory. If any theory that claims to be about "fundamental" understanding in cosmology and/or physics and it cannot predict the fairly specific nature of what the overwhelming majority of the Universe is composed of, then I say that theory is mere arm-waving. If it provides no definitive predictions, it is not science. It is still in a pseudo- science stage of development. RLO Discrete Scale Relativity [Mod. note: the weasel word here being 'definitive' -- mjh] |
#14
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WIMPs AWOL Again?
"Robert L. Oldershaw" wrote in
: Your two posts are somewhat contradictory. If any theory that claims to be about "fundamental" understanding in cosmology and/or physics and it cannot predict the fairly specific nature of what the overwhelming majority of the Universe is composed of, then I say that theory is mere arm-waving. If it provides no definitive predictions, it is not science. It is still in a pseudo- science stage of development. What, in your mind, constitutes a 'definitive' prediction? The bulk properties of dark matter are pretty nailed down. * Minimal or zero non-gravitational self interaction. * Zero electromagnetic interaction. * Most likely particulate in nature, due to massive observational exclusion of MACHO theories. * Nonrelativistic at decoupling, even more nonrelativistc now. * The equation of state for dark matter is that of dust, which is highly distinguishable between that of relativistic matter, photons, scalar and higher spin fields, etc. What further details are required of dark matter to explain cosmology better? The problem for the last few years is that particle physics has no answer. Did you know that the tools used to describe modern cosmology (GR and its' various solutions discovered over the years) all predate the standard model? Knowledge of composition is not required here, which is something you don't seem to grasp. By the way, do you stand by your claim that a neutron star size that spans a factor of 15 while extending into singularity territory is in any way definitive? Or do you think the double standards are ok? RLO Discrete Scale Relativity [Mod. note: the weasel word here being 'definitive' -- mjh] |
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WIMPs AWOL Again?
On Aug 21, 3:54*pm, Christian Froeschlin wrote:
I have to say I'm no expert on these theories, but it seems to me that adapting theories in light of new evidence is science, as long as there is still room to do so within previously existing constraints. In that case, there is not enough data to exclude the theory. If future research were to reveal that the existance of WIMPS 27 GeV would necessarily cause some observable effect, and that effect is never observed, then it would be possible to exclude the theory. It is only holding on to unmodified theories by ignoring inconvenient data that would be a problem. ---------------------------------------------------------------------------- Let me put things in the most simple form. Ideally we want theories that make definitive predictions that tell us whether the theory is fundamentally right, or fundamentally wrong. In the latter case, one does not "modify" the fundamentally wrong theory. One seeks a new model based on a new theoretical principle. We do not need epicycles. We need new and good ideas that lead to definitive predictions. RLO Discrete Scale Relativity |
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WIMPs AWOL Again?
On Aug 21, 5:23*pm, eric gisse wrote:
By the way, do you stand by your claim that a neutron star size that spans a factor of 15 while extending into singularity territory is in any way definitive? Or do you think the double standards are ok? ---------------------------------------------------------------------------------------------- To answer your question, the radius range for neutron stars is exactly the same as the radius range for subatomic nuclei, except that you must multiply the nuclear radii by a factor of 5.2 x 10^-17. This is a definitive prediction, regardless of how you want to misconstrue that. Robert L. Oldershaw http://www3.amherst.edu/~rloldershaw |
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WIMPs AWOL Again?
"Robert L. Oldershaw" wrote in
: Ideally we want theories that make definitive predictions that tell us whether the theory is fundamentally right, or fundamentally wrong. In the latter case, one does not "modify" the fundamentally wrong theory. One seeks a new model based on a new theoretical principle. Like for example, if one theory predicts dark matter is made of solar mass MACHOs but years of surveys only find some planets that make up a few percentage points, I suppose you would consider that an example of a theory that is fundamentally wrong. [Mod. note: quoted text trimmed. Please try to trim quoted text so that only directly relevant material is quoted -- mjh] |
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WIMPs AWOL Again?
In article , "Robert L.
Oldershaw" writes: Ideally we want theories that make definitive predictions that tell us whether the theory is fundamentally right, or fundamentally wrong. Agreed. In the latter case, one does not "modify" the fundamentally wrong theory. One seeks a new model based on a new theoretical principle. This is a straw-man argument. Most theories are not theories of everything which unanimously predict everything of interest. Most theories have some parameters which (as far as we know now) must be determined by observation. This does not mean that the theory is fundamentally wrong. For example, many new species of animals and plants are still being discovered. Our theories of biology are not fundamentally wrong on the grounds that they were not all predicted. In some cases, further progress on the theoretical side can allow one to predict things which were not possible in an older, coarser version of the theory. (While not as clear-cut, even postdictions are OK as long as they are unique and not adjustable. It is often an accident whether theory or observation is more advanced and accidents of human history have no bearing on the underlying physical reality.) I recommend John D. Barrow's book THEORIES OF EVERYTHING. It is about what we won't know even if we had a theory of everything (as the term is commonly used). Check it out. We do not need epicycles. Epicycles are, of course, an example of adjusting a theory to meet better observations, and rightly criticised for this. However, it is important to keep two things in mind. First, epicycles make a testable prediction, namely how the distance to a planet varies with time. The angular motion can be fit exactly with a sufficient number of epicycles (this is essentially Fourier synthesis (or analysis, depending one one's point of view), but measuring the distance can distinguish epicycles from other models. (To be sure, Copernicus's original heliocentric model was LESS accurate regarding positions of the planets, but, even disregarding the question of distance for the moment, in some sense more accurate because it is closer to the truth. This is the (perhaps undefinable) beauty of a theory which is often an indicator of what is right.) Also, the main reason Ptolemy's epicycles stayed around for so long is because the Church burned people who thought otherwise: not what we today understand as scientific discourse. Think of the so-called old quantum theory. It solved many problems in classical physics, but was not definitive. What happened? Was it replaced by a new paradigm? No, it was refined. Was there input from observation? Sure---how else would one know that it was not correct. Did this involve adjusting free parameters until they fit? No. It's still not a complete theory in some sense, but it is better than the old quantum theory. This is the way most science progresses. Kuhn's ideas about overthrowing the paradigm, with the Copernican revolution (a pun which many don't get) being an example, are mostly wrong since based on examples like this when it was not debate within science but rather the reduction of torture which allowed a new paradigm to arrive. (Also, Kuhn's ideas contain the seeds of their own distruction. Either they are scientific or not. If not, then we can ignore them. If they are, then by his own reasoning they will soon be replaced with a new paradigm.) We need new and good ideas that lead to definitive predictions. Right. And when these definitive predictions are falsified by other observations, one has to move on. The steady-state theory was, in almost all respects, a very good theory. It made testable predictions. They were falsified. Some people, like Bondi and Morison, moved on. Others, like Hoyle (who had done very good work in other areas), started to ignore reality. |
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"Robert L. Oldershaw" wrote in
: On Aug 21, 5:23*pm, eric gisse wrote: By the way, do you stand by your claim that a neutron star size that spans a factor of 15 while extending into singularity territory is in any way definitive? Or do you think the double standards are ok? ---------------------------------------------------------------------- - ----------------------- To answer your question, the radius range for neutron stars is exactly the same as the radius range for subatomic nuclei, except that you must multiply the nuclear radii by a factor of 5.2 x 10^-17. This is a definitive prediction, regardless of how you want to misconstrue that. Robert L. Oldershaw http://www3.amherst.edu/~rloldershaw How do you know that neutron stars fit inside such a range? You've been arguing for the past few days that science has ABSOLUTELY NO IDEA!!! how big a neutron star is. A proton (Hydrogen) is about 0.8 fm, and Uranium is [1] roughly 175,000 fm. So taking 10km as the middle of the neutron star range gives a rough upper limit of...two million kilometers? Using *your* "predicted" (when are you going to show how you obtained that prediction?) 6km gives an upper bound of about 1.8 million km. That's not even taking into account that random factor that you pulled out of the air. As for your claim that the range is the same, you aren't even within the correct order of magnitude. Factor of 15 vs factor of ~200,000. When your definitive prediction is incorrect by four orders of magnitude, are you going to add epicycles or just admit your theory is wrong? I consider this more of a test of how well you will stick to your claims regarding definitive predictions and the validity of a theory more than anything else, because you aren't even close to being correct here. By the way, I would like to know if you even LOOKED at the published litearture regarding neutron star radii. Did you? [1] - http://www.chemicool.com/elements/uranium.html#radius |
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WIMPs AWOL Again?
On Aug 22, 6:00*pm, eric gisse wrote:
Like for example, if one theory predicts dark matter is made of solar mass MACHOs but years of surveys only find some planets that make up a few percentage points, I suppose you would consider that an example of a theory that is fundamentally wrong. ------------------------------------------------------------------------------------------------ Have you read Mike Hawkins' preprint: "The case for primordial black holes as dark matter"? I think that he would vigorously disagree with your statement above. And bear in mind that he is a university professor who actually does scientific research and publishes scientific papers, rather than an amateur. You might consider 0.2 trillion unbound planetary-mass objects trivial, but I think if you had predicted them then you would be singing quite a different tune. RLO Fractal Cosmology |
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