The Case Against Dark Matter and Modified Gravity

The aspects of modern cosmology related with new physics, predicted by particle theory are discussed here. The models of inflation, baryosynthesis, dark matter and dark energy, physics of very early Universe, cosmological nucleosynthesis, origin and properties of cosmic microwave background radiation, formation of large scale structure of the Universe, role and distribution of dark matter in the modern Universe are discussed here.

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The Case Against Dark Matter and Modified Gravity

New postby Maxim Khlopov on Tue 12 Jan 2016 15:57

''The Case Against Dark Matter and Modified Gravity'' was presented by Dimitris Christodoulou in his VIA talk on 15.01.2016. The presentation is attached. The record of this lecture is in VIA library
http://viavca.in2p3.fr/dimitris_christodoulou.html
The following question was put during it:
Patrick Das Gupta: Very interesting talk, Prof. Christodoulou. I have one question concerning the use of pressure term and applying to spiral galaxies where the dominant matter is in the form of stars that have primarily regular and ordered motions. So, would the intrinsic solutions you described be applicable to the disk galaxies, in which stars move ballistically and are not in hydrostatic equilibrium?
You are welcome to continue discussion in replies to this post
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Re: The Case Against Dark Matter and Modified Gravity

New postby Maxim Khlopov on Tue 12 Jan 2016 16:00

D.Christodoulou propagates these papers in support for his approach.
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Re: The Case Against Dark Matter and Modified Gravity

New postby DChristodoulou-822 on Tue 12 Jan 2016 20:45

On the same topic, there is one more paper that I wrote back in 2007.
It can be found in arXiv:

http://arxiv.org/abs/0706.3205

It describes an application of my solution of the Lane-Emden equation for the protosolar nebula.
I am not going to talk about this topic on Friday, but this application is based on the same mathematics:
The fact that the new solution of the LE equation couples density to rotation in a unique way.
Therefore, by fitting the solution to the current solar system, one may derive fundamental physical properties of the long-gone nebula. Assuming of course that our giant planets have not migrated by more than 3 AU in either direction.

The paper was not published because of disagreement on the application, not the mathematics. The referee offered me to publish only the math in the tradition of Chandrasekhar (who had done some work on the LE equation), but I refused to do that. I am not in the habit of publishing math with no connection to physical applications.
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Re: The Case Against Dark Matter and Modified Gravity

New postby Shantanu on Fri 22 Jan 2016 19:06

Thank you for an interesting talk. Sorry I missed it. But I watched most of it (except for about twenty minutes
when there was a problem with sound). Anyhow does your model explain Tully-Fisher relation and the empirical observation that asymptotic accelerations for all DM dominated system is always constant. (This is usually interpreted
as evidence for MOND). Also can you explain the Sandage timing argument which uses the relative velocity between
us and M31 to argue for dark matter in our galaxy
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Re: The Case Against Dark Matter and Modified Gravity

New postby DChristodoulou-822 on Fri 22 Jan 2016 22:18

No, this model does not explain the TF relation, just as no other model does.
To explain the TF relation, Demos Kazanas has always maintained that one additional parameter is needed beyond the fundamental plane.

Modified Dynamics does not explain this relation either. Depending on various samples of galaxies chosen, the slope in the relation varies between 3.5 and 4. In Modified Dynamics, the slope is precisely 4, and there is no way to produce shallower slopes. In dark matter and Newtonian Gravity, this relation is entirely absent---and this is the reason that Demos has always thought that we need to search for another parameter.

As for arguments based on larger than galactic scales, my models have nothing to say. Flat rotation curves
are observed in scales of 10-100 kpc, and this is where my solutions are applicable. Larger scales are an open issue, but I have always thought that the evidence is not as concrete as in galactic scales.
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Re: The Case Against Dark Matter and Modified Gravity

New postby Shantanu on Mon 25 Jan 2016 18:49

Apologies if this messageappears twice (but somehow I do not find my reply)
Anyhow the timing argument paper by Sandage from 1980s can be found
http://adsabs.harvard.edu/abs/1986ApJ...307....1S and was used to estimate mass
of local group (including our galaxy) and so is independent evidence (complimentary to rotation
curves) for DM in our galaxy.
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