Huh … can't make heads or tails of this paper

[BeAChooser]

https://arxiv.org/pdf/2107.00138.pdf

Effects of non-vanishing dark matter pressure in the Milky Way Galaxy

Is “non-vanishing dark matter” a new gnome or just a bunch of gobbledegook?

[jacmac]

Non-vanishing is not the only confusing part for me.

The structure, morphology and evolution of galaxies are currently based on two important assumptions ......
The first requirement is the presence of super-massive black hole.......
The second is the unavoidable existence of dark matter (DM) HALOS SURROUNDING every galaxy......
The existence of DM is today strongly confirmed by several independent observations [3]. Although such observations suggest that DM does exist, its nature, microphysics and fundamental properties are still unknown, and so far no suitable DM candidates have been directly detected [4–7]

If their theory places a dark matter halo around the galaxies, why would that not attract the outer stars and matter further out from the galactic center ? The theory itself seems backwards. Shouldn't the DM be well within the galaxies to help hold it together... ???

Of course, the only real non-vanishing part is their belief in dark matter

[paladin17]

If their theory places a dark matter halo around the galaxies, why would that not attract the outer stars and matter further out from the galactic center ?

The answer is called shell theorem.

[Roshi]

If their theory places a dark matter halo around the galaxies, why would that not attract the outer stars and matter further out from the galactic center ?

The answer is called shell theorem.

Yes, this theorem helps them in case of dark matter. What about star and planet formation when only gravity is taken into acount? Imagine a giant ball of gas or a field of rocks. Particles are not even pulled towards one single point. In adition to this, in case of gas, there is this thing called "pressure". (Even in space).

Why doesn't the atmosphere collapse to the surface of the Earth? Because of gas pressure.
And they say gravity is strong enough to hold together a mass of hydrogen the size of the Sun, and while this mass of hydrogen is exploding...

[jacmac]

paladin17:

The answer is called shell theorem.

Got it !
thanks.

[Harry]

The core of a Star or the the Core of a Galaxy is made up of dense matter, in the form of a condensate that has various transients from Neutron Matter and so on to Axion Gluon matter.
The dipolar electromagnetic vector fields are omnipotent in explaining the formation of Star Glass Nebulae and spiral arms.