Question Does "dark matter" flow into black holes, and if not, why not?

The concept of "dark matter" has been accepted as a form of matter that does not interact with light or with regular matter by any mechanism other than gravity. It is supposed to be heavily concentrated in galaxies, adding mass that increases the orbital speeds of stars and bends light as it passes by at a great distance.

However, I have not read about how it behaves, otherwise.

It seems to me that it should flow into black holes quite easily, considering that it does not absorb energy from the stars' radiation and apparently does not emit any radiation, itself.

So, unless it has some sort of self-repulsion, I would expect it to simply fall into black holes even more readily than visible matter does.

But, that would seem to be a process that would deplete the relative density of dark matter in the centers of galaxies, compared to the density of regular matter. Is that what we see?

Or, is there some need to infer some sort of self-repulsion by dark matter, so that it develops some sort of "dark pressure" that limits its density?

Thoughts?
 
Feb 14, 2020
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The concept of "dark matter" has been accepted as a form of matter that does not interact with light or with regular matter by any mechanism other than gravity. It is supposed to be heavily concentrated in galaxies, adding mass that increases the orbital speeds of stars and bends light as it passes by at a great distance.

However, I have not read about how it behaves, otherwise.

It seems to me that it should flow into black holes quite easily, considering that it does not absorb energy from the stars' radiation and apparently does not emit any radiation, itself.

So, unless it has some sort of self-repulsion, I would expect it to simply fall into black holes even more readily than visible matter does.

But, that would seem to be a process that would deplete the relative density of dark matter in the centers of galaxies, compared to the density of regular matter. Is that what we see?

Or, is there some need to infer some sort of self-repulsion by dark matter, so that it develops some sort of "dark pressure" that limits its density?

Thoughts?
Dark Matter is everywhere including where matter-energy is which we know is sparse and similarly where there is higher density of matter as in neutron stars or blackholes. DM creates all matter-energy from itself. Please see my April 13, 2022 post in this community.
 
Sep 11, 2020
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In my opinion Black holes are inside of space time and dark matter is not so it does not drain into a black hole. It can be condensed into Liquid Dark Matter(LDM) as it circulates through the galaxy. If the black hole becomes active it will cause the LDM to vaporize into Gaseous Dark Matter(GDM) which will lower the concentration of dark matter in the galaxy. The vaporized dark matter will blast out of the poles pulling regular matter with it. Eventually the turbulence on the edges of the jets will cause entrained LDM to vaporize Which will reheat and further accelerate the jets. Once the jets run out of LDM they will mushroom out coalesce with gas/dust and rain back down if not on this galaxy on the next one that comes down the filament.
 
Feb 14, 2020
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Ed
Greetings!
Adjectives LDM GDM apply to what is matter, other than the fact that Gravity is created while matter-energy are being formed by DM, there are no such attributes directly associated with DM. However, DM to Matter Energy (ME) transformation will exhibit properties of those phases in which the created ME comes into being or during the transformation.

Thanks.
Ravi
(Dr. Ravi Sharma, Ph.D. USA)
NASA Apollo Achievement Award
Chair, Ontology Summit 2022
Particle and Space Physics
Senior Enterprise Architect
 
Dec 29, 2022
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From the images I have seen, the center of our galaxy appears to be a rotating braid of plasma. I'll bet it has a net positive charge. And I'll bet the center of that spin has a humongous magnetic dipole field. I'd say any wondering charge that got inside that ring, would be accelerated N and S of the rotation. Who knows, it might be fed on a regular basis. The electrons would be charged and contracted to the proton level, anti-protons. Then gamma radiation could proceed. But we get two gigantic galactic bubbles of fuel. If those two bubbles discharged......it would put a super nova to shame. The ultimate destruction. A little, big bang.

It could have already happened thousands of years ago, and we not know it.

The past we haven't seen yet.
 
I would think DM could be drawn into any gravity well, including BHs. The reason it would be hard to find much on this is because both are invisible. We must infer their presence. Surrounding visible matter reveals a BH, or gravity waves in tight binaries. But what would reveal the accreting of DM?
 
Nov 19, 2021
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Here is an article says Dark Matter is not drawn into Black Holes. If it did, the distribution of Black Holes and galaxies would be much different than it is.

"“Over the billions of years since galaxies formed, such runaway absorption of dark matter in black holes would have altered the population of galaxies away from what we actually observe,” said Hernandez

Astronomers Find Black Holes Do Not Absorb Dark Matter (universetoday.com)
 
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Billslugg, I get a "forbidden" message when I click on your link. Is there another way to find the article?

The idea that black matter does not flow into black holes seems contrary to the idea that it does not interact with regular matter, but has gravitational attraction to regular matter and itself.

I get conflicting statements from the "Internet explainers", whom I distinguish from actual theorists, about the distribution of dark matter around galaxies. Some seem to think that it is in more of a hollow halo around galaxies than in a blob centered in galaxies. If that is true, then it would seem reasonable to suspect depletion of the dark matter near the center as it could be drawn into the black hole in some fashion different than the behavior we see for regular matter. Otherwise, it would need to have some sort of self-repulsion to limit its density.

If we want to learn what it really is, it seems to me that we need to understand why it has the distribution(s) that we can detect.

Otherwise, it is stil just a fudge factor that is allowed to do whatever it is "needed" to do to make the cosmological model work as presently conceived.
 
Thanks for the paper link. I read it, and, as I understand it, the paper assumes that dark matter does get captured by black holes. It uses a lot of assumptions and calculations to infer that dark matter could not exceed a specific density in the past without causing runaway accretion of dark matter into black holes that would have depleted the density of dark matter halos below what we "observe" today. I put "observe" in quotes because we actually can't observe it, we can only infer it from observations of regular matter.

It would have been nice if the authors had illustrated their paper with radial density curves of dark matter, but they did not. So, we are left with trying to interpret some rather nebulous language about where in the galaxies dark matter has various densities, n their opinion.

Anyway, it seems that the assumption is that dark matter gets captured by black holes similarly to regular matter. And, given the other numerous assumptions, I would not take this paper as a "proof" that dark matter could not have exceeded their limiting value in the past. That seems at odds with the idea that dark matter was created in a big bang and expanded to its current density profile. But, that same problem occurs with regular matter, and is "handled" in the theory by unbridled assumptions about the effects of "inflation".

One of the questions in my mind when I read things like this is whether the authors/theorists have addressed all of the issues related to their study. For instance, when I see papers that claim that relativistic frame dragging of rotating visible matter alone can account for star velocities in galaxies, and compare that to arguments that infer dark matter to provide the explanation for galactic star velocities, I wonder if anybody is asking themselves what the effect of the dark matter would be on the frame dragging effect. If dark matter does exist, then it seems that the proper solution should include its additional effect on the frame dragging caused by rotating matter with gravitational attraction. But, I have not seen that addressed, so I don't know if it is normally included or not. The current Big Bang Theory sometimes reminds me of the old joke about the group of blind men trying to describe an elephant by each just touching single parts of it - and disagreeing on the results.
 
OK, I read the article from the Google search, and it puts a different "spin" on the conclusions, saying that dark matter probably needs to be thought of as having some limit on how it gets absorbed by black holes.

I also read some of the other articles from the search. They really aren't very convincing. The one from "Ask Ethan" (https://www.forbes.com/sites/starts...les-and-dark-matter-interact/?sh=1a3862f33994 ) uses the current inferred distribution of dark matter to "show" that dark matter does not contribute most of the mass of a black hole. But, it really doesn't show why the current distribution of dark matter around a galaxy could not be the result of the dark matter near the center already being depleted by capture into the black hole. It just does not have any explanation for why normal matter "dominates" the center of galaxies while dark matter dominates the much larger outer regions, even well beyond where visible matter is hardly noticeable.

It doesn't take much of a stretch of imagination to wonder if there was an early runaway of dark matter coalescing into black holes that kick started galaxy formation in the early universe, which then stopped or slowed for some reason. That might help the folks who are staring to get squeezed on time for galactic formation between the current model predictions and the new Webb observations.

Not that I am encouraging such things, but I note that we know so little about dark matter that theorists could make up just about any "rules" about how it behaves, and those would not be any more speculative than the introduction of "inflation" that makes all of space do the things necessary to make the BBT "work".

So, what I do like to see is the first type of paper that at least looks at the ramifications of some of the ideas to help contrain the speculative "fitting" to some extent.
 
Here is one of the papers that looks at very early black holes:
https://www.universetoday.com/15991...easting-800-million-years-after-the-big-bang/ It looks like a very active black hole feeding in a rather low-mass galaxy.

So, it does seem to me to be very likely that there was some sort of transition in the behavior of black holes within the visible universe. We can see extremely active black holes, "Quasars", in the distant universe, but apparantly not in the nearest, most recent time frame. So, some sort of change seems likely with time, rather than just assuming it was like it is here and now, just closer together 13 billion years ago.