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A Black Snag in the Black Matter  Cocorico !

Speeds of rotation of the Milky Way
Rotation curves of the components of the Milky Way (source F. Combes)

 Gravitation and Rotation of Galaxies
While measuring rotational speeds of galaxies, astronomers perceived very quickly a flagrant systematic anomaly: galaxies don't turn as they should. They turn in almost constant speeds, in other words, rotational speeds are too rapid at the periphery of galaxies, as compared to what they should be according to the universal gravitation laws. (Let us note that we could assert as well the opposite, Has knowledge that the speed of rotation is insufficient towards the centre of the galaxies)
This suggests the existence of an invisible heavy matter, the black matter, distributed in a halo surrounding galaxies, and representative more than 90% of the total mass of the galaxy. The graph opposite shows that.
Or even of a modification of the universal gravitation laws at weak intensities, which means in big scales (MOND)
In the figure opposite, the green dotted curve shows the rotation speed of the disc D, The black dotted curve represent the rotation speed of the bulb B.
Plots, in form of red pictograms, are measurements of the speed of the gas (atomic Hydrogen) in and near the galaxy.
 We note that the gas seems indeed follow the almost horizontal blue curve, which represente the sum of the speeds of all the components of the Milky Way. We use this caracteristique to assert that the speed of rotation of the gas is a good indicator of the speed of rotation of the galaxy. But to explain this horizontal curve it is necessary to take place a halo H, representing a mysterious black mattter (brown dots). (Sources: Françoise Combes).
Rotation curve of NGC 2403

Opposite : 

  1. Curve of rotation "observed" of NGC 2403 (pictograms) and curves of rotation of the individual massive components (lines).
    Source: Begeman (1987). 
  2. Rotation curves "observed" on NGC 5033 (pictograms) and rotation curves of the individual massive components (lines).
  3. Rotation curves "observed" on NGC 5371 (pictograms) and rotation curves of the individual massive components (lines).

As we can notice, it seems that in all galaxies the gas component has always a rotation curve different from that of the disc.

Notice also that to explain it we always require a "halo" constituted by a hypothetical "black matter".

Questions:

Why do we measure different speeds of rotation for the different components of the galaxy? And more particularly as regards the disc and the gas?
Is it allowed, from the point of view of the physics, to add, by slices of distances, the speeds of these components and to make the averages?
Rotation curve of NGC 5033
Rotation curve of NGC 5371
 
Snag
  1. The first object is the disc which is constituted of massive objects (stars, planets, dust, etc.)
  2. The second object is the gas made of atomic hydrogen having weak density, which is detected only because it is ionized and so partially but lesser, of molecular Hydrogen and Helium
(Source : NASA-WMAP)
Magnetic Field of the CMB 
What is the physical difference which could explain their individual speeds of rotation?
Both are sensitive to the universal gravitation. But the gas, contrary to the disc, is extremely little dense, and as it is ionized, it is very sensitive to the global magnetic field of the galaxy! This last one would be very weak, of the order of  0,8 µG. But it is distributed in the whole of the galaxy and even beyond. That is in large-scale, its influence on the gas becomes dominant compared with that of the gravitation.
Conclusions :
Steam engine

  1. The rotation curve of the gas is not a serious indicator of the speed of rotation of the galaxies.

  2. On the other hand, the rotation curve of the gas is a good indicator of the presence of a large-scale galactic magnetic field.

  3. Adding the speeds of the galactic components, to make it averages, is a grave conceptual fault. It is the physical error which means to make the average of the speed of a steam engine with the speed of the smoke belched out by its fireplace.

  4. We do not need black matter to explain the rotation speed of the galaxies.
And in clusters of galaxies?
Abell 2218 (Source: HST) In every clusters of galaxies we observe gravitational lenses. These reveal us the presence of distant objects from which the light is deflected (in a sense refracted) by the mass of the cluster.
The calculation (relativity) allows to go back up to the mass of the cluster. But the mass so calculated is much superior to the mass obtained by the sum of all the objects observed in the cluster.
This conflict seems be able to be explained by the existence of a black matter Or still by a modification of the laws of the universal gravitation in weak intensity, that is in big scales (MOND).
 
Galaxies Cluster Abell 1689 (Source Chandra) The"Chandra X-Ray Observatory" gave us numerous images og galaxy clusters.
Abell 1689 is a good example. We see that this cluster of galaxies is inside a colossal cloud of gas. This one is excited by the light of the galaxies. It is thus ionized.
But is it influenced, for all that, by a magnetic field? Yes, it is indeed what appears according to certain observations. (Magnetic Fields in Galaxy Clusters). And these magnetic fields have a typical value of 1 µG. But then in this case, the black matter that some believe to have revealed in clusters, would be, there also, only an error of interpretation.
It would be necessary to explain how are produced the gravitational lenses. But are they gravitational?
Could not involve lenses of optical origin? The cloud of gas of the cluster would be rather dense to make us this joke? Or more simply, in this scale, that would not be the density which would be important, but rather the number of atoms of gas which the light would meet in its trajectory.
Or still this famous magnetic field, for which we look, which would divert the light.
 
Cluster Abell 520 (Source: NASA) The "Dark Matter Core Defies Explanation" in the image of Abell 520 published by the HST on March 2nd, 2012.
Question: would it be here also about a ionized heap of gas inside a magnetic field?
 
Une atteinte sérieuse à la théorie de la matière noire ?
 New

On April 18th, 2012, the ESO publishes, under the title: "Serious Blow to Dark Matter Theories?", the observations made around the Sun and in the galaxy, by a team of astronomers in Chile, which showed that the theory of the black matter don't agree to the observationnels facts.
We can thus suppose that the attempts of detection, in a direct way, of black matter particles on Earth risk very probably to bring no result.
It is the most precise study never realized on the movements of stars in the Milky Way. It found no proof of the presence of black matter in a relatively big zone around the Sun.
 
Milky Way is Surrounded by Halo of Hot Gas
 New

On September 24th, 2012, the NASA publishes the X Ray observation, made by Dr Anjali Gupta et al with Chandra Observatory, under the title: "NASA's Chandra Shows Milky Way is Surrounded by Halo of Hot Gas".
This observation shows, once again, that it is better to trust observations rather than simulations.
Other observations of this kind made on other galaxies or clusters of galaxies could eliminate definitively the hypotheses of "black matter" and also "MOND".

Question :
Would our Galaxy be an unique case, an exceptional case?
 
Documentations
to
consult
  1. The Dark Matter Myth - Magnetic Fields and Galactic Rotation Curves (Thomas Smid)
  2. SPH simulations of magnetic fields in galaxy clusters (Dolag K. Bartelmann M. Lesch H.)
  3. The rotation curve of spiral galaxies and its cosmological implications (It's a PS file which we can read with Ghostscript or convert in PDF format with Adobe Acrobat
  4. Birth Control for Stars
  5. Anchoring Magnetic Field in Turbulent Molecular Clouds
  6. L'Univers des Galaxies - Daniel Benest, Alain Blanchard, Lucie Bottinelli, Suzy Collin, Claude Froeschlé, Lucienne Gouguenheim, Jean Lefèvre et Laurent Nottale - Chez  HACHETTE - Collection les Fondamentaux.
  7. Hydrodynamique . Physique - Etienne Guyon, Jean-Pierre Hulin et Luc Petit - EDP SCIENCES.
  8. The Baryonic Tully-Fischer Relation. (Stacy McGaugh).
    IAP-CNRS (Roger Ferlet) A fast history and a summary of the results of the observations).
  9. Accepted view of Universe challenged by astronomer.
  10. EdgeviewSpace.
  11. Les Données de BOOMERanG suggèrent un Univers purement Baryonique (Stacy McGaugh).
  12. L'image Astronomique du Jour, Logarithmic Spirals Isabel and M51. A link which could be justifiable.
  13. Propriétés et origine des reliques radio dans les amas de galaxies. (Chiara Ferrari).
  14. arXiv:astro-ph/0308518 v1 28 Aug 2003 - A Dearth of Dark Matter in Ordinary Elliptical Galaxies. Aaron J. Romanowsky, Nigel G. Douglas, Magda Arnaboldi, Konrad Kuijken, Michael R. Merrifield, Nicola R. Napolitano, Massimo Capaccioli, Kenneth C. Freeman.
  15. June 27th, 2005, On a retrouvé la matière noire dans les galaxies elliptiques ! But we did not still find the slightest sample of black matter.
  16. Observational Cosmology: caveats and open questions in the standard model (Martín López-Corredoira - 01/06/2006).

  17.  New  May 11th, 2010, We did not still find the slightest sample of black matter: First Dark Matter Results from the XENON100 Experiment.
    And also: Early Results from Large Dark Matter Detector Cast Doubt on Earlier Claims.

  18.  New  Serious Blow to Dark Matter Theories?
    See the abstract (Source ESO).
""When presented with two possibilities, scientists tend to choose the wrong one" (HaltonaArp - SeeingaRed)
 

Created: 01/08/09
Last release: 14/07/15 

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