[ExI] Dark Matter

BillK pharos at gmail.com
Sun Nov 10 22:41:54 UTC 2013


I thought that I understood that dark matter was the invisible 'glue'
holding galaxies together.
i.e. Observation shows that the rotational speed of galaxies is such
that there must be invisible dark matter present that stops the galaxy
flying apart.

But a casual comment in a documentary I have just watched used the
phrase 'web of dark matter'. So I checked, and it appears that there
are filaments of dark matter that link galaxies together.

<http://www.cosmosmagazine.com/news/scientists-shine-light-dark-matter/>
Quote:
She added: “Our standard picture of cosmology tells us that filaments
of invisible matter thread through the universe, and this bridge of
dark matter connecting two clusters is exactly what we would expect.”
The research confirms that galaxy clusters form at the intersections
of these vast filaments of dark matter.

<http://arstechnica.com/science/2012/07/dark-matter-is-the-thread-connecting-galaxy-clusters/>
Quote:
Simulations of the Universe on the largest scales show an unexpected
resemblance to nerve cells in the human brain, with galaxy clusters
playing the role of the cell body and thinner filaments of matter
linking them like axons.

These observations lend strong support to the theory that the Universe
is built on a web of dark matter that has drawn in visible structures
like galaxies and clusters.

The large-scale structure (LSS) of the Universe that's predicted by
the most widely accepted cosmological model involves long filaments of
dark matter. Where these filaments intersect, large dark matter halos
grow, and these provide the gravity for ordinary matter to collect.
The largest halos become galaxy clusters, the biggest objects in the
Universe held together by their own gravity. Surveys of galaxies show
that the distribution of clusters corresponds to the predictions of
LSS theory, providing strong indirect evidence for the existence of
dark matter.
-----------

I find the scale of these structures a bit mind boggling.
So I think I'll sit quiet for a while until the boggle factor returns to normal.


BillK




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