Is this enough for Dark Matter?

[SLD]

https://news.stanford.edu/news/2012/february/slac-nomad-planets-022312.html

This is an old article that I found linked to a newer one on a recent Brown Dwarf find. According to the article, there are 100,000 such rogue planets for every star. If their average mass is the same as earth's, then there’s not enough to make a difference in mass to explain the galaxy rotation problem. But if they are Jupiter size, then there’s too much. But Jupiter is about 1000 times earth's mass, and 1/1000 of a solar mass. Dark matter seems to take up ten times galactic mass.

Another article I read stated that brown dwarfs were as plentiful as stars, which would account for an additional 1% of the galactic mass. Not much.

Thoughts?

SLD

 

[Jobar]

Interesting. I knew that there were theories that there was enough normal baryonic matter which we couldn't detect to make up the missing mass, but I didn't know that there was evidence backing it up.

Still, that's six years old. If we haven't heard more about it, I figure that no further evidence for it has emerged yet, and it may be the result of some error.

 

[skepticalbip]

The galaxy rotation problem isn't so much missing mass as it is the distribution of that mass. The problem is that there needs to be more mass in the galaxy's outer edge or halo to account for the observed rotation curve. More mass in the main disc would only make the problem more pronounced. Perhaps this could solve the problem if all those rogue planets and brown dwarfs had been slung out of the galaxy's main disc and into the halo.

 

[repoman]

Gonna use quote marks here, is there a range of "viscosity", "friction" and particle-particle interaction that dark matter would have in order to coalesce somewhat in the outer halo but not everywhere in the galaxy?

If dark matter had ZERO viscosity and friction could it even be in its current distribution?

Perhaps it is experiencing friction but that means it is releasing "something" (either standard matter, light or another type of dark matter) even if a glacial pace. This is in the same way that friction of normal matter releases sound waves, infrared radiation and so on.

It must be harder for dark matter to collapse gravitational when the matter is in a massive spinning space cloud which is what galaxies are. This is because it is doesn't much or at all shed energy from particle collisions and frictional heating followed by heat loss by radiation.

But the dark matter cloud around the standard matter would be gravitationally tugged. After a long while, would it not match the baryonic matter velocity around the galactic center?

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Ok, gonna spitball, crackpot here for fun. Imagine if dark matter is all a remnant of the big bang and for dark matter to convert to baryonic matter (and vice versa) it would require energy on scales maybe even above the "wow particle" level. Dark matter is stuck as it is and there is almost never enough "activation energy" for it to be converted baryonic matter. The "activation energy" at this symmetry breaking would be a lot closer to the Planck energy, like somewhere around that of Electroweak combining with Strong.

Now could there be many forms or particles of dark matter that interact only with dark matter other than gravity.


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If there was a dark matter particle produced in the LHC, would not that show up as a massive "poof into thin air"? All of the energy, momentum, spin etc.. that the dark matter particle contains would be missing from the collision byproducts.

But what is the LHC is just too weak to get any dark matter production?