Spiral and Disk Galaxies are controlled by single parameter. What and How?

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Jonathan Scott

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Bath water forms a vortex because the planet rotates.

The resultant of collapsing gas clouds will not rotate if it did not have initial angular momentum.

http://www.loc.gov/rr/scitech/mysteries/coriolis.html
It's a myth that the rotation of the earth has anything to do with the bath water vortex.

It's also statistically implausible (as Chalnoth has also said) that the random component of angular momentum would add up to zero, or even anywhere close. That's like throwing a coin thousands of times and having it come out with exactly the same number of heads and tails.
 

Chalnoth

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As I said before, the best evidence for dark matter comes from studies where the systematic errors are relatively well-understood. The systematic errors are not well-understood for galaxies, and thus a discrepancy that we see there is more likely to do with our model of the galaxies themselves instead of fundamental physics.
 
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It's a myth that the rotation of the earth has anything to do with the bath water vortex.

It's also statistically implausible (as Chalnoth has also said) that the random component of angular momentum would add up to zero, or even anywhere close. That's like throwing a coin thousands of times and having it come out with exactly the same number of heads and tails.
I am not sure I understand the analogue that flipping a coin a million times has on the finding that spiral/disk galaxies are simpler (patterned, controlled) than expected.

The point is random physical events and properties that should affect the spiral galaxy such as new gas in falling, mergers with other galaxies, the initial rotation of the gas cloud, redshift when the galaxy initial formed, the metallicity of gas in the galaxy, and so on, are overridden by some parameter or mechanism.

http://arxiv.org/abs/0811.1554


Galaxies appear simpler than expected

Galaxies are complex systems the evolution of which apparently results from the interplay of dynamics, star formation, chemical enrichment, and feedback from supernova explosions and supermassive black holes. The hierarchical theory of galaxy formation holds that galaxies are assembled from smaller pieces, through numerous mergers of cold dark matter. The properties of an individual galaxy should be controlled by six independent parameters including mass, angular-momentum, baryon-fraction, age and size, as well as by the accidents of its recent haphazard merger history. Here we report that a sample of galaxies that were first detected through their neutral hydrogen radio-frequency emission, and are thus free of optical selection effects, shows five independent correlations among six independent observables, despite having a wide range of properties. This implies that the structure of these galaxies must be controlled by a single parameter, although we cannot identify this parameter from our dataset. Such a degree of organisation appears to be at odds with hierarchical galaxy formation, a central tenet of the cold dark matter paradigm in cosmology.
 
271
0
It's a myth that the rotation of the earth has anything to do with the bath water vortex.

It's also statistically implausible (as Chalnoth has also said) that the random component of angular momentum would add up to zero, or even anywhere close. That's like throwing a coin thousands of times and having it come out with exactly the same number of heads and tails.
Because we were discussing spin, this additional quote from Disney et al's paper seems relevant. Does Disney's statement make sense?

http://arxiv.org/abs/0811.1554

If, as we have argued, galaxies come from at most a six-parameter set, then for gaseous galaxies to appear as a one-parameter set, as observed here, the theory of galaxy formation and evolution must supply five independent constraint equations to constrain the observations. This is such a stringent set of requirements that it is hard to imagine any theory, apart from the correct one, fulfilling them all. For instance, consider heirarchical galaxy formation in the dark matter model, which has been widely discussed in the literature3,4. Even after extensive simplification, it still contains four parameters per galaxy: mass, spin, halo-concentration index and epoch of formation.

Consider spin alone, which is thought to be the result of early tidal torquing. Simulations produce spins, independent of mass, with a log-normal distribution. Higher-spin discs naturally cannot contract as far; thus, to a much greater extent than for low-spin discs, their dynamics is controlled by their dark halos, so it is unexpected to see the nearly constant dynamical-mass/luminosity ratio that we and others14 actually observe. Heirarchical galaxy formation simply does not fit the constraints set by the correlation structure in the Equatorial Survey.
 

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