Does dark matter come in two types?
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From: eric gisse on 20 Jun 2010 17:57 dlzc wrote: > Dear eric gisse: > > On Jun 14, 4:11 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> dlzc wrote: >> > Dear eric gisse: >> >> > On Jun 13, 9:34 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> >>dlzc wrote: >> >> >> [...] >> >> >> > How can you keep a straight face, decrying non-physical >> >> > "Dark Fluid" or TeVeS, for non-physical, >> >> > arbitrarily-distributed Dark Matter? >> >> >> Because it is neither. >> >> > It cannot be touched, or detected in any way that these >> > other "non-physical" theories do not predict. >> >> Dark matter does not model cause, only effect. > > It is is still non-physical (based on evidence), and arbitrary. 1) Bullet cluster. Looks physical to me. 2) Perfect fluid with zero pressure, and no observed non-gravitational interactions. Yeah, that's really arbitrary. > >> Ask particle physics if you want to know the answer. It >> is suspected that the particle will interact only via the >> weak interaction and gravitation. > > It was proposed to only interact via gravitation. Since we keep > trying to turn it into "something", we have to rule out the other > "three forces". Certainly isn't interacting via E&M or the strong force. > >> The arbitrary fields crowd can only shrug, or try >> to deflect. > > Fields of DM... Not even remotely close to the same thing conceptually, mathematically, or physically. Dark matter is 1 parameter: density. Nothing else. [...] > Look at any paper that talks about DM distribution, or even just > galactic behaviors. First thing they do is derive a M/L for that > galaxy, concentrating at the center, to apply to the rest of the > galaxy. They can't see all the matter, so they use this luminosity > "yardstick"... The mass-to-light ratio is irrelevant to the argument (plus I thought you were using mass-to-length) because the _shape_ of the rotation curve is the only relevant piece of information when describing the generalities of the situation. If you want to argue that the assumptions of a massive central core and relatively lighter spiral arms are wrong, you'll have to do a LOT better than this. > > For examples: > http://www.physics.smu.edu/~kehoe/ugradRes/kv_thesis.pdf > ... page 4. Look at the SHAPE OF THE CURVE. That is not what is observed. Welcome to mid-20th century observational astronomy. Now catch up to the late 20th/21st century by learning about gravitational lensing. You find that the gravitational mass disagrees strongly with the visible mass, and coupled with cluster mergers we can conclude...? Plus, just for giggles, http://www.naic.edu/~rminchin/virgohi21.html > http://www.ifa.hawaii.edu/~barnes/ast626_05/dmdg.pdf > ... bottom of page 2. > > They do it, because they were taught to do it that way. For fucks sake. This argument is stupid no matter how it is invoked. > Rather than > simply accepting that the "local" rotational speed describes the > normal mass inside that orbit. Uh, that's what's assumed. Pay attention. Speed of orbit is a direct function of the interior mass. Read your own references. > They *invent* DM to cover this hoary > mistake. > >> >> > Guys, "DM" is likely just unlit normal matter. >> >> >Probably ionized, so that it has limited capacity to >> >> > re-radiate (like the missing normal matter between >> >> > us and quasars). >> >> >> Uuuuuuhhhh, not a chance. >> >> > That was adult. To be expected when you are >> > responding in this mode. >> >> How wrong does something have to be before I don't have >> to take it seriously? >> >> A gram of ionized Hydrogen has more attractive force >> than the entire planet put together. What mechanism do >> you propose to maintain this charge separation? > > Did you not realize the stuff also is washing across our own > heliosheath, and is in close company with unbonded electrons? You seem to be under the impression that an ionized plasma can stay fully ionized *and* maintain charge separation. It doesn't work that way - not anywhere near completely. > Now you > are pulling lint form your pockets, rather than thinking. > >> What mechanism do you propose which suppresses all >> radiation from the from the separated protons and electrons? > > Same thing that works for solar wind. The solar wind is quite visible in the radio range. > Both charges have roughly the > same average motion (until magnetic fields kick in). > >> How do your proposed mechanisms line up with what is >> observed in the bullet cluster and similar collisions? >> >> The notion is wrong. I shouldn't even have to explain it, >> because it is *that wrong*. > > Not all the intergalactic gas collided and got hot. Most of it > continued on, just like the stars that are no longer surrounded by > their host dust clouds. We cannot see point light sources. > > We can look at Andromeda, and we can see the errors in applying M/L to > infer distribution of normal mass. We can see anomalous collections > of "dust" at least. But we do it anyway. > > MOND is out. TeVeS is out. DM is out. It is just normal matter, and > an accounting error. But a *lot* of normal matter... microlensing > works, because there is sufficient normal matter to accomplish it. http://www.naic.edu/~rminchin/virgohi21.html No. > > David A. Smith
From: dlzc on 22 Jun 2010 18:15 Dear eric gisse: On Jun 20, 2:57 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > dlzc wrote: > > On Jun 14, 4:11 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > >>dlzc wrote: > >> > On Jun 13, 9:34 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > >> >>dlzc wrote: > > >> >> [...] > > >> >> > How can you keep a straight face, decrying > >> >> > non-physical "Dark Fluid" or TeVeS, for > >> >> > non-physical, arbitrarily-distributed Dark Matter? > > >> >> Because it is neither. > > >> > It cannot be touched, or detected in any way that > >> > these other "non-physical" theories do not predict. > > >> Dark matter does not model cause, only effect. > > > It is is still non-physical (based on evidence), and > > arbitrary. > > 1) Bullet cluster. Looks physical to me. It did not interact. How physical is that? But then neither did the stars that should have been visible from those two clusters. > 2) Perfect fluid with zero pressure, and no observed > non-gravitational interactions. .... despite them looking for weak interactions... > Yeah, that's really arbitrary. Sure seems that way. How do we detect the charge matter impinging on our heliosheath? Can we do that over lightyears, then megamarsecs, for stellarsheaths? > >> Ask particle physics if you want to know the answer. It > >> is suspected that the particle will interact only via the > >> weak interaction and gravitation. > > > It was proposed to only interact via gravitation. Since > > we keep trying to turn it into "something", we have to > > rule out the other "three forces". > > Certainly isn't interacting via E&M or the strong force. Lots of things don't interact that way when they are heated to tens of millions of degrees, and allowed to plow on through mostly empty space. > >> The arbitrary fields crowd can only shrug, or try > >> to deflect. > > > Fields of DM... > > Not even remotely close to the same thing > conceptually, mathematically, or physically. > Dark matter is 1 parameter: density. Nothing else. Distrtibution, arbitrary. Fit to observed data. How arbitrary! > [...] > > > Look at any paper that talks about DM distribution, > > or even just galactic behaviors. First thing they do > > is derive a M/L for that galaxy, concentrating at the > > center, to apply to the rest of the galaxy. They > > can't see all the matter, so they use this luminosity > > "yardstick"... > > The mass-to-light ratio is irrelevant to the argument > (plus I thought you were using mass-to-length) > because the _shape_ of the rotation curve is the > only relevant piece of information when describing > the generalities of the situation. No. The mass is inferred form the luminosity. The assumption is as I describe. And the "normal mass deficit", therefore the "required Dark Matter" derives form the assumption. > If you want to argue that the assumptions of a > massive central core and relatively lighter spiral arms > are wrong, you'll have to do a LOT better than this. Vice versa. The central area is swept clear (this we know), and is very hot (and therefore more luminous, this we know). So it appears to require Dark Matter where none is required. The rotation curves describe the *normal* matter. We didn't have rotation curves when the M/L method was devised. > > For examples: > >http://www.physics.smu.edu/~kehoe/ugradRes/kv_thesis.pdf > > ... page 4. > > Look at the SHAPE OF THE CURVE. That is not > what is observed. Welcome to mid-20th century > observational astronomy. > > Now catch up to the late 20th/21st century by > learning about gravitational lensing. Works for normal mass too. > You find that the gravitational mass disagrees > strongly with the visible mass, and coupled with > cluster mergers we can conclude...? That we can't see point light sources, and we can't see ionized gas (unless it quenches). > Plus, just for giggles, http://www.naic.edu/~rminchin/virgohi21.html Link thrown twice. See below. > >http://www.ifa.hawaii.edu/~barnes/ast626_05/dmdg.pdf > > ... bottom of page 2. > > > They do it, because they were taught to do it that way. > > For fucks sake. This argument is stupid no > matter how it is invoked. No, Eric, it is not. > > Rather than > > simply accepting that the "local" rotational > > speed describes the normal mass inside that > > orbit. > > Uh, that's what's assumed. Pay attention. No, it's not. The normal mass is assigned from an old method, based on assumptions we know are incorrect. > Speed of orbit is a direct function of the interior > mass. Read your own references. That is what I said. You just assume the mass is normal + Dark, based on an assumption that "everybody" makes. Namely M/L. I've provided two links that form that same conclusion. Yet you cannot see the nose in front of your own face. > > They *invent* DM to cover this hoary > > mistake. > > >> >> > Guys, "DM" is likely just unlit normal matter. > >> >> >Probably ionized, so that it has limited capacity to > >> >> > re-radiate (like the missing normal matter between > >> >> > us and quasars). > > >> >> Uuuuuuhhhh, not a chance. > > >> > That was adult. To be expected when you are > >> > responding in this mode. > > >> How wrong does something have to be before I don't have > >> to take it seriously? > > >> A gram of ionized Hydrogen has more attractive force > >> than the entire planet put together. What mechanism do > >> you propose to maintain this charge separation? > > > Did you not realize the stuff also is washing across > > our own heliosheath, and is in close company with > > unbonded electrons? > > You seem to be under the impression that an ionized > plasma can stay fully ionized *and* maintain charge > separation. It doesn't work that way - not anywhere > near completely. Apparently you haven't been paying attention: http://www.physorg.com/news192799714.html .... ionized hydrogen and oxygen missing five electrons... detected because of *absoprtion*, not emission. > > Now you > > are pulling lint form your pockets, rather than thinking. > > >> What mechanism do you propose which suppresses > >> all radiation from the from the separated protons and > >> electrons? > > > Same thing that works for solar wind. > > The solar wind is quite visible in the radio range. It is unknown, and invisible, until it interacts with matter that allows it to quench. You can see evidence of this in the samplers that have been used. > > Both charges have roughly the > > same average motion (until magnetic fields kick in). > > >> How do your proposed mechanisms line up with what is > >> observed in the bullet cluster and similar collisions? > > >> The notion is wrong. I shouldn't even have to explain it, > >> because it is *that wrong*. > > > Not all the intergalactic gas collided and got hot. Most > > of it continued on, just like the stars that are no longer > > surrounded by their host dust clouds. We cannot see > > point light sources. > > > We can look at Andromeda, and we can see > > the errors in applying M/L to infer distribution > > of normal mass. We can see anomalous collections > > of "dust" at least. But we do it anyway. > > > MOND is out. TeVeS is out. DM is out. It is > > just normal matter, and an accounting error. But > > a *lot* of normal matter... microlensing works, > > because there is sufficient normal matter to > > accomplish it. > > http://www.naic.edu/~rminchin/virgohi21.html > > No. Unconvinced. Talking spiral galaxies here, and *known* errors in M/L assumption. David A. Smith
From: eric gisse on 22 Jun 2010 22:41 dlzc wrote: > Dear eric gisse: > > On Jun 20, 2:57 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> dlzc wrote: >> > On Jun 14, 4:11 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> >>dlzc wrote: >> >> > On Jun 13, 9:34 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> >> >>dlzc wrote: >> >> >> >> [...] >> >> >> >> > How can you keep a straight face, decrying >> >> >> > non-physical "Dark Fluid" or TeVeS, for >> >> >> > non-physical, arbitrarily-distributed Dark Matter? >> >> >> >> Because it is neither. >> >> >> > It cannot be touched, or detected in any way that >> >> > these other "non-physical" theories do not predict. >> >> >> Dark matter does not model cause, only effect. >> >> > It is is still non-physical (based on evidence), and >> > arbitrary. >> >> 1) Bullet cluster. Looks physical to me. > > It did not interact. How physical is that? Gravitational lensing says something is there. Do you have reason to disagree? > But then neither did the > stars that should have been visible from those two clusters. Stars do not meaningfully participate in a cluster meregr beyond their contribution to gravitation. Direct hits are a bit on the rare side. > >> 2) Perfect fluid with zero pressure, and no observed >> non-gravitational interactions. > > ... despite them looking for weak interactions... Read my words carefully. "No observed non-gravitational interactions". The scattering cross section of a neutrino would fit nicely within cluster merger data sets. > >> Yeah, that's really arbitrary. > > Sure seems that way. How do we detect the charge matter impinging on > our heliosheath? Radio, direct contact with magnetometers. > Can we do that over lightyears, then megamarsecs, > for stellarsheaths? If you had a baseline big enough and could distinguish heliopause radio noise from not only the background but from the parent star itself, sure. > >> >> Ask particle physics if you want to know the answer. It >> >> is suspected that the particle will interact only via the >> >> weak interaction and gravitation. >> >> > It was proposed to only interact via gravitation. Since >> > we keep trying to turn it into "something", we have to >> > rule out the other "three forces". >> >> Certainly isn't interacting via E&M or the strong force. > > Lots of things don't interact that way when they are heated to tens of > millions of degrees, and allowed to plow on through mostly empty > space. Does synchrotron radiation not count? Regardless, light scatters like crazy through plasma. That stuff would be shining like a beacon if it were what you thought. I do not know how to make it more clear to you that dark matter can not be ionized gas without beating you to death with an E&M textbook, then a plasma physics textbook for good measure. > >> >> The arbitrary fields crowd can only shrug, or try >> >> to deflect. >> >> > Fields of DM... >> >> Not even remotely close to the same thing >> conceptually, mathematically, or physically. >> Dark matter is 1 parameter: density. Nothing else. > > Distrtibution, arbitrary. Fit to observed data. How arbitrary! *rolls eyes* > >> [...] >> >> > Look at any paper that talks about DM distribution, >> > or even just galactic behaviors. First thing they do >> > is derive a M/L for that galaxy, concentrating at the >> > center, to apply to the rest of the galaxy. They >> > can't see all the matter, so they use this luminosity >> > "yardstick"... >> >> The mass-to-light ratio is irrelevant to the argument >> (plus I thought you were using mass-to-length) >> because the _shape_ of the rotation curve is the >> only relevant piece of information when describing >> the generalities of the situation. > > No. The mass is inferred form the luminosity. Not relevant. Look at the rotation curves. The exact value for mass is relevant for quantification but not for describing the gross features of the potential. > The assumption is as I > describe. And the "normal mass deficit", therefore the "required Dark > Matter" derives form the assumption. Sure. That's quantification. Now look at the rotation curves that mesh with the observed matter, then what's actually observed. > >> If you want to argue that the assumptions of a >> massive central core and relatively lighter spiral arms >> are wrong, you'll have to do a LOT better than this. > > Vice versa. The central area is swept clear (this we know), An odd claim given the observational fact that the central core of a galaxy has a higher stellar density than the outer areas. Unless you mean the absolute center where the supermassive black hole is located. That's only sortof true, and only over a few cubic parsecs. > and is > very hot (and therefore more luminous, this we know). The 'central area' is as much vacuum as the outer area. Temperature is not a meaningful parameter. > So it appears > to require Dark Matter where none is required. The rotation curves > describe the *normal* matter. We didn't have rotation curves when the > M/L method was devised. LOOK AT THE ROTATION CURVES. You keep talking as if they don't exist and aren't relevant. > >> > For examples: >> >http://www.physics.smu.edu/~kehoe/ugradRes/kv_thesis.pdf >> > ... page 4. >> >> Look at the SHAPE OF THE CURVE. That is not >> what is observed. Welcome to mid-20th century >> observational astronomy. >> >> Now catch up to the late 20th/21st century by >> learning about gravitational lensing. > > Works for normal mass too. Normal mass is ruled out. Welcome to late 20th/21st century observational astronomy. > >> You find that the gravitational mass disagrees >> strongly with the visible mass, and coupled with >> cluster mergers we can conclude...? > > That we can't see point light sources, and we can't see ionized gas > (unless it quenches). Urrrrrr....? We can see point light sources quite fine - we call them stars. We can also see ionized gas VERY WELL. Open a plasma physics textbook. > >> Plus, just for giggles, > http://www.naic.edu/~rminchin/virgohi21.html > > Link thrown twice. See below. > >> >http://www.ifa.hawaii.edu/~barnes/ast626_05/dmdg.pdf >> > ... bottom of page 2. >> >> > They do it, because they were taught to do it that way. >> >> For fucks sake. This argument is stupid no >> matter how it is invoked. > > No, Eric, it is not. Yeah, it is. "But that's how you were taught, you don't think!!!" is a rather familiar rallying cry from a large percentage of this newsgroup. [snip repetitions]
From: dlzc on 23 Jun 2010 00:37 Dear eric gisse: On Jun 22, 7:41Â pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > dlzc wrote: > > On Jun 20, 2:57 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > >>dlzcwrote: > >> > On Jun 14, 4:11 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > >> >>dlzcwrote: > >> >> > On Jun 13, 9:34 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > >> >> >>dlzcwrote: > > >> >> >> [...] > > >> >> >> > How can you keep a straight face, decrying > >> >> >> > non-physical "Dark Fluid" or TeVeS, for > >> >> >> > non-physical, arbitrarily-distributed Dark Matter? > > >> >> >> Because it is neither. > > >> >> > It cannot be touched, or detected in any way that > >> >> > these other "non-physical" theories do not predict. > > >> >> Dark matter does not model cause, only effect. > > >> > It is is still non-physical (based on evidence), and > >> > arbitrary. > > >> 1) Bullet cluster. Looks physical to me. > > > It did not interact. Â How physical is that? Â > > Gravitational lensing says something is there. Do you > have reason to disagree? Something is there. > > But then neither did the > > stars that should have been visible from those two > > clusters. > > Stars do not meaningfully participate in a cluster > meregr beyond their contribution to gravitation. Direct > hits are a bit on the rare side. Right. So the "lensing dark stuff" includes most of the stars. Yet it is dark. > >> 2) Perfect fluid with zero pressure, and no observed > >> non-gravitational interactions. > > > ... despite them looking for weak interactions... > > Read my words carefully. "No observed non-gravitational > interactions". > > The scattering cross section of a neutrino would fit nicely > within cluster merger data sets. But the stars don't, and we can't see them. > >> Yeah, that's really arbitrary. > > > Sure seems that way. Â How do we detect the charge > > matter impinging on our heliosheath? > > Radio, direct contact with magnetometers. > > > Can we do that over lightyears, then megamarsecs, > > for stellarsheaths? > > If you had a baseline big enough and could distinguish > heliopause radio noise from not only the background > but from the parent star itself, sure. I'd like to see the stellarsheath of Barnard's star, or V385 Carinae... http://www.space.com/scienceastronomy/puffy-star-cosmic-jellyfish-photo-100622.html .... how much matter is it plowing through... > >> >> Ask particle physics if you want to know the answer. It > >> >> is suspected that the particle will interact only via the > >> >> weak interaction and gravitation. > > >> > It was proposed to only interact via gravitation. Â Since > >> > we keep trying to turn it into "something", we have to > >> > rule out the other "three forces". > > >> Certainly isn't interacting via E&M or the strong force. > > > Lots of things don't interact that way when they are heated > > to tens of millions of degrees, and allowed to plow on > > through mostly empty space. > > Does synchrotron radiation not count? No magnetic fields, for the most part. > Regardless, light scatters like crazy through plasma. Dense plasma, sure. > That stuff would be shining like a beacon if it were what > you thought. I do not know how to make it more clear > to you that dark matter can not be ionized gas without > beating you to death with an E&M textbook, then a > plasma physics textbook for good measure. I provided a link, where hydrogen and O5- plasma was undetectable, invisible, until we looked at X-ray absorption. How long can you stand in ignorance, and act proud? > >> >> The arbitrary fields crowd can only shrug, or try > >> >> to deflect. > > >> > Fields of DM... > > >> Not even remotely close to the same thing > >> conceptually, mathematically, or physically. > >> Dark matter is 1 parameter: density. Nothing else. > > > Distrtibution, arbitrary. Â Fit to observed data. Â How > arbitrary! > > *rolls eyes* *meaningful comment* > >> [...] > > >> > Look at any paper that talks about DM distribution, > >> > or even just galactic behaviors. Â First thing they do > >> > is derive a M/L for that galaxy, concentrating at the > >> > center, to apply to the rest of the galaxy. Â They > >> > can't see all the matter, so they use this luminosity > >> > "yardstick"... > > >> The mass-to-light ratio is irrelevant to the argument > >> (plus I thought you were using mass-to-length) > >> because the _shape_ of the rotation curve is the > >> only relevant piece of information when describing > >> the generalities of the situation. > > > No. Â The mass is inferred form the luminosity. > > Not relevant. Look at the rotation curves. "All normal mass" will produce an identical rotation curve. > The exact value for mass is relevant for quantification > but not for describing the gross features of the potential. Without the M/L error, we'd find that there is no requirement for CDM. > > The assumption is as I describe. Â And the "normal > > mass deficit", therefore the "required Dark Matter" > > derives form the assumption. > > Sure. That's quantification. Now look at the rotation > curves that mesh with the observed matter, then what's > actually observed. The normal mass curve is established from luminosity. Which is an error. You can generate the exact same rotation curve with all normal matter. > >> If you want to argue that the assumptions of a > >> massive central core and relatively lighter spiral arms > >> are wrong, you'll have to do a LOT better than this. > > > Vice versa. Â The central area is swept clear (this we > know), > > An odd claim given the observational fact that the central > core of a galaxy has a higher stellar density than the > outer areas. http://iopscience.iop.org/0004-637X/559/1/326/fulltext .... Introduction "showed signatures of a single rotating disk with the center swept clear of material" http://iopscience.iop.org/1538-4357/488/2/L149/975374.text.html .... Conclusions. The model of the Milky Way worked if "the â¼0.1 pc region of the Galaxy, ... is swept clear of gas" > the absolute center where the supermassive black hole is > located. That's only sortof true, and only over a few cubic > parsecs. It is larger than that, that is swept clear. And this is the region that has hotter more luminous stars, and less unlit mass than further out. > > and is > > very hot (and therefore more luminous, this we know). > > The 'central area' is as much vacuum as the outer area. > Temperature is not a meaningful parameter. It directly relates to luminosity. How can you keep making the same mistakes? > > Â So it appears > > to require Dark Matter where none is required. Â The > > rotation curves describe the *normal* matter. Â We > > didn't have rotation curves when the M/L method was > > devised. > > LOOK AT THE ROTATION CURVES. You keep talking > as if they don't exist and aren't relevant. The rotation curves define the amount of mass. The M/L mistake defines Dark Matter, the rotation curve, and microlensing does not. Ask yourself how they know how much *normal* matter is in a given region of a galaxy? > >> > For examples: > >> >http://www.physics.smu.edu/~kehoe/ugradRes/kv_thesis.pdf > >> > ... page 4. > > >> Look at the SHAPE OF THE CURVE. That is not > >> what is observed. Welcome to mid-20th century > >> observational astronomy. > > >> Now catch up to the late 20th/21st century by > >> learning about gravitational lensing. > > > Works for normal mass too. > > Normal mass is ruled out. Welcome to late 20th/21st > century observational astronomy. You ignored the link. Late 20th. Hydrogen and O5- plasma (the "missing normal matter") is invisible except by absorption of X-rays from more distant quasars. Normal matter, yet Dark. > >> You find that the gravitational mass disagrees > >> strongly with the visible mass, and coupled with > >> cluster mergers we can conclude...? > > > That we can't see point light sources, and we can't > > see ionized gas (unless it quenches). > > Urrrrrr....? We can see point light sources quite fine - > we call them stars. OK, then where are the stars in the bullet cluster, the ones that didn't get involved in the stellar collision, but would be where you mythical Dark Matter is? Point light sources, something the size of a star at that distance... CANNOT be imaged. It depends on dust clouds and other stars to be visible. > We can also see ionized gas VERY WELL. Open a > plasma physics textbook. X-rays. Please quit arguing from ignorance. > >> Plus, just for giggles, > >http://www.naic.edu/~rminchin/virgohi21.html > > > Link thrown twice. Â See below. > > >> >http://www.ifa.hawaii.edu/~barnes/ast626_05/dmdg.pdf > >> > ... bottom of page 2. > > >> > They do it, because they were taught to do it that way. > > >> For fucks sake. This argument is stupid no > >> matter how it is invoked. > > > No, Eric, it is not. > > Yeah, it is. "But that's how you were taught, you don't > think!!!" is a rather familiar rallying cry from a large > percentage of this newsgroup. > > [snip repetitions] Snip the appropriate link, because you'd rather argue than think. Let's try it again: http://sciencemag.org/cgi/content/abstract/319/5859/55 Ask yourself how they know how much *normal* matter is in a given region of a galaxy? David A. Smith
From: eric gisse on 23 Jun 2010 02:14
dlzc wrote: [...] >> Gravitational lensing says something is there. Do you >> have reason to disagree? > > Something is there. Baryonic matter is wholly excluded, and leptons can't make the mass budget. Ruh roh. > >> > But then neither did the >> > stars that should have been visible from those two >> > clusters. >> >> Stars do not meaningfully participate in a cluster >> meregr beyond their contribution to gravitation. Direct >> hits are a bit on the rare side. > > Right. So the "lensing dark stuff" includes most of the stars. Yet > it is dark. Welcome to the conundrum. > >> >> 2) Perfect fluid with zero pressure, and no observed >> >> non-gravitational interactions. >> >> > ... despite them looking for weak interactions... >> >> Read my words carefully. "No observed non-gravitational >> interactions". >> >> The scattering cross section of a neutrino would fit nicely >> within cluster merger data sets. > > But the stars don't, and we can't see them. Yeah, we do. Rather clearly, actually. > >> >> Yeah, that's really arbitrary. >> >> > Sure seems that way. How do we detect the charge >> > matter impinging on our heliosheath? >> >> Radio, direct contact with magnetometers. >> >> > Can we do that over lightyears, then megamarsecs, >> > for stellarsheaths? >> >> If you had a baseline big enough and could distinguish >> heliopause radio noise from not only the background >> but from the parent star itself, sure. > > I'd like to see the stellarsheath of Barnard's star, or V385 > Carinae... > http://www.space.com/scienceastronomy/puffy-star-cosmic-jellyfish- photo-100622.html > ... how much matter is it plowing through... Lots, and the source of it is the star itself. Supergiants spew. > >> >> >> Ask particle physics if you want to know the answer. It >> >> >> is suspected that the particle will interact only via the >> >> >> weak interaction and gravitation. >> >> >> > It was proposed to only interact via gravitation. Since >> >> > we keep trying to turn it into "something", we have to >> >> > rule out the other "three forces". >> >> >> Certainly isn't interacting via E&M or the strong force. >> >> > Lots of things don't interact that way when they are heated >> > to tens of millions of degrees, and allowed to plow on >> > through mostly empty space. >> >> Does synchrotron radiation not count? > > No magnetic fields, for the most part. Observationally false. > >> Regardless, light scatters like crazy through plasma. > > Dense plasma, sure. *ANY* plasma. There is an obvious cutoff but if you argue that the density is so tenuous that it doesn't even scatter radio waves across the 25,000 light years between us and intergalactic space, you will have a hard time making the argument that there's *enough* to matter. > >> That stuff would be shining like a beacon if it were what >> you thought. I do not know how to make it more clear >> to you that dark matter can not be ionized gas without >> beating you to death with an E&M textbook, then a >> plasma physics textbook for good measure. > > I provided a link, where hydrogen and O5- plasma was undetectable, > invisible, until we looked at X-ray absorption. How long can you > stand in ignorance, and act proud? *scratches head* Why are you inverting the argument? I've been claiming all along that plasma absorbs E&M. It isn't as if X-ray telescopes are 'new' technologies. You'll note that Chanda X-ray observations were one of the principle measurements behind the publication of the bullet cluster. > >> >> >> The arbitrary fields crowd can only shrug, or try >> >> >> to deflect. >> >> >> > Fields of DM... >> >> >> Not even remotely close to the same thing >> >> conceptually, mathematically, or physically. >> >> Dark matter is 1 parameter: density. Nothing else. >> >> > Distrtibution, arbitrary. Fit to observed data. How >> arbitrary! >> >> *rolls eyes* > > *meaningful comment* > >> >> [...] >> >> >> > Look at any paper that talks about DM distribution, >> >> > or even just galactic behaviors. First thing they do >> >> > is derive a M/L for that galaxy, concentrating at the >> >> > center, to apply to the rest of the galaxy. They >> >> > can't see all the matter, so they use this luminosity >> >> > "yardstick"... >> >> >> The mass-to-light ratio is irrelevant to the argument >> >> (plus I thought you were using mass-to-length) >> >> because the _shape_ of the rotation curve is the >> >> only relevant piece of information when describing >> >> the generalities of the situation. >> >> > No. The mass is inferred form the luminosity. >> >> Not relevant. Look at the rotation curves. > > "All normal mass" will produce an identical rotation curve. > >> The exact value for mass is relevant for quantification >> but not for describing the gross features of the potential. > > Without the M/L error, we'd find that there is no requirement for CDM. Unless we look at globular clusters, gravitational lensing, virial mass estimates, cluster mergers... > >> > The assumption is as I describe. And the "normal >> > mass deficit", therefore the "required Dark Matter" >> > derives form the assumption. >> >> Sure. That's quantification. Now look at the rotation >> curves that mesh with the observed matter, then what's >> actually observed. > > The normal mass curve is established from luminosity. The *ROTATION CURVE* is a direct function of distance from galactic center and speed. Identification with how much mass is there is model dependent, but irrelevant to the argument as the curves speak directly to the enclosed mass. > Which is an > error. You can generate the exact same rotation curve with all normal > matter. I look forward to the paper that addresses all my concerns. > >> >> If you want to argue that the assumptions of a >> >> massive central core and relatively lighter spiral arms >> >> are wrong, you'll have to do a LOT better than this. >> >> > Vice versa. The central area is swept clear (this we >> know), >> >> An odd claim given the observational fact that the central >> core of a galaxy has a higher stellar density than the >> outer areas. > > http://iopscience.iop.org/0004-637X/559/1/326/fulltext > ... Introduction "showed signatures of a single rotating disk with the > center swept clear of material" > http://iopscience.iop.org/1538-4357/488/2/L149/975374.text.html > ... Conclusions. The model of the Milky Way worked if "the ?0.1 pc > region of the Galaxy, ... is swept clear of gas" The scale of a galaxy is confusing you. The milky way is ~125,000 light years wide. 1 pc - the relevant distance scale surrounding Sgr. A* - is only 3.2 light yeras. When I say 'central core' I mean the luminous portion that is approximately 1/5 of the surface area of the overall galaxy. Not the same, not even close. [...] >> > So it appears >> > to require Dark Matter where none is required. The >> > rotation curves describe the *normal* matter. We >> > didn't have rotation curves when the M/L method was >> > devised. >> >> LOOK AT THE ROTATION CURVES. You keep talking >> as if they don't exist and aren't relevant. > > The rotation curves define the amount of mass. Subject to the modeling assumptions used. > The M/L mistake > defines Dark Matter, the rotation curve, and microlensing does not. > Ask yourself how they know how much *normal* matter is in a given > region of a galaxy? Virial theorem, dynamics if a galaxy is bound to another, gravitational lensing, Tully-Fisher relation. Pick one. > >> >> > For examples: >> >> >http://www.physics.smu.edu/~kehoe/ugradRes/kv_thesis.pdf >> >> > ... page 4. >> >> >> Look at the SHAPE OF THE CURVE. That is not >> >> what is observed. Welcome to mid-20th century >> >> observational astronomy. >> >> >> Now catch up to the late 20th/21st century by >> >> learning about gravitational lensing. >> >> > Works for normal mass too. >> >> Normal mass is ruled out. Welcome to late 20th/21st >> century observational astronomy. > > You ignored the link. Late 20th. Hydrogen and O5- plasma (the > "missing normal matter") is invisible except by absorption of X-rays > from more distant quasars. Normal matter, yet Dark. What's there to see? Plasma is visible, as is well known. > >> >> You find that the gravitational mass disagrees >> >> strongly with the visible mass, and coupled with >> >> cluster mergers we can conclude...? >> >> > That we can't see point light sources, and we can't >> > see ionized gas (unless it quenches). >> >> Urrrrrr....? We can see point light sources quite fine - >> we call them stars. > > OK, then where are the stars in the bullet cluster, the ones that > didn't get involved in the stellar collision, but would be where you > mythical Dark Matter is? Stars are visible. We don't see stars. Ergo.. > Point light sources, something the size of a > star at that distance... CANNOT be imaged. zuh? > It depends on dust clouds > and other stars to be visible. An interesting assertion. Just so we are clear, are you seriously claiming that a star becomes invisible after a certain point regardless of its' luminosity? > >> We can also see ionized gas VERY WELL. Open a >> plasma physics textbook. > > X-rays. Please quit arguing from ignorance. .....and? My point has been rather consistently that plasma is absorbs E&M. I've been deliberately vague at what frequency it does because that's a function of charge density. > >> >> Plus, just for giggles, >> >http://www.naic.edu/~rminchin/virgohi21.html >> >> > Link thrown twice. See below. >> >> >> >http://www.ifa.hawaii.edu/~barnes/ast626_05/dmdg.pdf >> >> > ... bottom of page 2. >> >> >> > They do it, because they were taught to do it that way. >> >> >> For fucks sake. This argument is stupid no >> >> matter how it is invoked. >> >> > No, Eric, it is not. >> >> Yeah, it is. "But that's how you were taught, you don't >> think!!!" is a rather familiar rallying cry from a large >> percentage of this newsgroup. >> >> [snip repetitions] > > Snip the appropriate link, because you'd rather argue than think. > Let's try it again: > http://sciencemag.org/cgi/content/abstract/319/5859/55 Given the mass-energy budget of the universe is something like 5% baryonic, you can quadruple the amount of baryons in the universe and still be factor of 4 on top of that short. That we may not know the true amount of matter 'out there' is neither insightful or surprising. The point is that there _is not enough as far as we can tell_. > > Ask yourself how they know how much *normal* matter is in a given > region of a galaxy? Obviously you think its' a wild assed guess. Saying the assumptions used by cosmology are all wrong is easy - anyone can, and does, do that. Saying modern cosmology is 'all wrong', but what is not nearly as easy is making a coherent and rational argument as to why. I know you think ionized matter can do it. I see your opinion is apparently validated by the discovery of 'hidden' plasma with X-ray telescopes. But that's simply not enough. Look carefully at the bullet cluster picture. See the bow shock from the ionized normal matter? Why doesn't your solution for dark matter interact with that? You need to apply the known rules of physical reality consistently, not selectively. > > David A. Smith |