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Yes, Within The Galactic Limits

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Posted by Richard Ruquist on September 27, 2002 15:57:27 UTC

The gravitational analyses suggest that Dark Matter is in the form of a sphere that surrounds each galaxy. So Dark Matter exists in the vacuum of space within galaxies but not outside the galactic limits.

However, I cannot understand how the analyses can put limits on Dark Matter. It is possible that Dark Matter fills the inter-galactic space as well. So It may lie within the cluster limits.

Galaxies are not like stars where there is considerable distance between them compared to their size. The inter-galactic distance within clusters is roughly ten times the size of the galaxies according to what I have read. So it does not take much extra Dark Matter to fill the entire cluster.

It is also possible that Dark Matter density is non-uniform, since it interacts on a gravitational basis with visible matter, such that it exists at higher densities in side galaxies, at still higher densities within solar systems, and still higher densities within or near stars and planets.

But since Dark Matter is about ten times more massive on the whole than visible matter, the gravitational effects of visible matter must be just a perturbation on the distribution of Dark Matter.

It follows that Dark Matter cannot be composed of axions alone, because being bosons, the axions would rapidly collapse into black holes if they were they only constituents. Remember that they have no inherent motiuon in space to keep them from collapse as is the case with stars. So there must be other chargeless constituents of dark matter because they are Fermions with sufficient motion to prevent collapse, or perhaps Pauli exclusion or Dark Energy plays a role preventing collapse. We have much to learn about Dark Matter.

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