Does dark matter come in two types?
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From: dlzc on 13 Jun 2010 23:49 Dear eric gisse: On Jun 13, 4:47 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > Yousuf Khan wrote: > > On 6/13/2010 1:13 PM, eric gisse wrote: > >> Yousuf Khan wrote: > >>> On 6/10/2010 7:11 AM, eric gisse wrote: > >>>> Bullet cluster. > > >>> Hardly conclusive of anything, lots of alternative > >>> explanations than Dark Matter. > > >> Precious few. > > >> MOND? laff > >> TeVeS? Shifts the problem back exactly 1 step via > >> insertion of almost completely arbitrary vector & > >> scalar fields. > > >> How many dark matter alternatives survive scrutiny > >> of the bullet cluster in isolation? > > > A: Dark Fluid. > > > Dark Fluid not only explains the Bullet Cluster, it also > > explains the Train Wreck Cluster (Abell 520). Dark > > Fluid also avoids the "Black Hole trap" that affected > > TeVeS, because there is a built-in repulsive force > > element, otherwise known as Dark Energy. > > > *** > > Has 'dark fluid' saved Earth from oblivion? > > "The dark fluid can also reconcile the observations of > > what happened in the Bullet and train-wreck clusters. > > Whereas previous modified gravity theories cannot > > explain why the two collisions ended up differently, > > this is not a problem with Zhao's theory because the > > distribution of the dark fluid - and therefore of the > > enhanced gravity effect - can vary. > > > Zhao likens the interaction between visible matter and > > the dark fluid to the interplay between wind and the > > surface of an ocean. Disturbances in one will affect the > > other, but depending on how the disturbances were > > created and the surrounding conditions, ocean > > turbulence can overshoot wind turbulence or lag behind > > it. In the case of the Bullet cluster, the dark fluid may > > have sloshed forward, piling up beyond the visible > > matter. In the train wreck, the fluid may have lagged > > behind visible matter. " > >http://www.philosophychatforum.com/viewtopic.php?f=2&t=8478 > > http://arxiv.org/abs/0711.0958 > > Their general Lagrangian eats up a half dozen models > of gravitation which couple to the Ricci scalar in some > linear fashion, including TeVeS. The problem is, once > again, pushed back a step. > > Instead of dark energy (vacuum energy from QFT) and > dark matter (some yet- undiscovered particle that only > interacts via the weak interaction) you have the presence > of rather arbitrary scalar and vector fields which have > literally NO physical basis. > > Is that REALLY better? Think about it. How can you keep a straight face, decrying non-physical "Dark Fluid" or TeVeS, for non-physical, arbitrarily-distributed Dark Matter? Seriously, Dark Matter arises because M/L near a galactic center is assumed to be correct across the spiral. Even though the center is swept clear (making M/L non-representative of anything except the center), and we can see in many cases anomalous distributions of unlit normal matter further out towards the rim (and even more beyond the rim). 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). David A. Smith
From: eric gisse on 14 Jun 2010 00:34 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. > > Seriously, Dark Matter arises because M/L near a galactic center is > assumed to be correct across the spiral. That is not why. Do not argue about which you do not understand. > Even though the center is > swept clear (making M/L non-representative of anything except the > center), and we can see in many cases anomalous distributions of unlit > normal matter further out towards the rim (and even more beyond the > rim). It is abundantly clear to me that you have never seen even one rotation curve that plots velocity as a function of radius. > > 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. > > David A. Smith
From: dlzc on 14 Jun 2010 13:15 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. Both the theories you despise, and DM, has to "map" to the arbitrary distribution that Nature provides. It is both. > > Seriously, Dark Matter arises because M/L near a > > galactic center is assumed to be correct across the > > spiral. > > That is not why. Do not argue about which you do not > understand. I do understand. That is where it comes from. I have asked those who know, and they neither laughed, nor denyed it. > > Even though the center is swept clear (making M/L > > non-representative of anything except the center), > > and we can see in many cases anomalous > > distributions of unlit normal matter further out towards > > the rim (and even more beyond the rim). > > It is abundantly clear to me that you have never seen > even one rotation curve that plots velocity as a function > of radius. It is abundantly clear to me that you have never paid attention that the mass curve (to which the differential is applied as DM), is based on the luminosity. Using a ratio calibrated to a galaxy center. So it describes, it would appear, just normal matter... no DM required. > > 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. David A. Smith
From: eric gisse on 14 Jun 2010 19:11 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. 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. The arbitrary fields crowd can only shrug, or try to deflect. > Both the theories you despise, and > DM, has to "map" to the arbitrary distribution that Nature provides. > It is both. > >> > Seriously, Dark Matter arises because M/L near a >> > galactic center is assumed to be correct across the >> > spiral. >> >> That is not why. Do not argue about which you do not >> understand. > > I do understand. That is where it comes from. I have asked those who > know, and they neither laughed, nor denyed it. Then they weren't paying attention. The ACTUAL reason is because the visible matter distribution creates a potential that does not mesh with the potential that stars are actually following. > >> > Even though the center is swept clear (making M/L >> > non-representative of anything except the center), >> > and we can see in many cases anomalous >> > distributions of unlit normal matter further out towards >> > the rim (and even more beyond the rim). >> >> It is abundantly clear to me that you have never seen >> even one rotation curve that plots velocity as a function >> of radius. > > It is abundantly clear to me that you have never paid attention that > the mass curve (to which the differential is applied as DM), is based > on the luminosity. Using a ratio calibrated to a galaxy center. So > it describes, it would appear, just normal matter... no DM required. Is that a guess or are there actual papers based on this idea? I think its' a guess. > >> > 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? What mechanism do you propose which suppresses all radiation from the from the separated protons and electrons? 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*. > > David A. Smith
From: dlzc on 14 Jun 2010 20:38
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. > 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". > The arbitrary fields crowd can only shrug, or try > to deflect. Fields of DM... > > Both the theories you despise, and > > DM, has to "map" to the arbitrary distribution that > > Nature provides. It is both. > > >> > Seriously, Dark Matter arises because M/L near a > >> > galactic center is assumed to be correct across the > >> > spiral. > > >> That is not why. Do not argue about which you do not > >> understand. > > > I do understand. That is where it comes from. I have > > asked those who know, and they neither laughed, nor > > denyed it. > > Then they weren't paying attention. The ACTUAL reason > is because the visible matter distribution Based on M/L, already pointed out as being faulty... > creates a potential that does not mesh with the > potential that stars are actually following. Because the M/L factor established at the galactic center is faulty. > >> > Even though the center is swept clear (making M/L > >> > non-representative of anything except the center), > >> > and we can see in many cases anomalous > >> > distributions of unlit normal matter further out towards > >> > the rim (and even more beyond the rim). > > >> It is abundantly clear to me that you have never seen > >> even one rotation curve that plots velocity as a function > >> of radius. > > > It is abundantly clear to me that you have never paid > > attention that the mass curve (to which the differential > > is applied as DM), is based on the luminosity. Using > > a ratio calibrated to a galaxy center. So it describes, > > it would appear, just normal matter... no DM required. > > Is that a guess or are there actual papers based on this > idea? > > I think its' a guess. 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"... For examples: http://www.physics.smu.edu/~kehoe/ugradRes/kv_thesis.pdf .... page 4. 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. Rather than simply accepting that the "local" rotational speed describes the normal mass inside that orbit. 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? 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. 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. David A. Smith |