Is there a maximum mass for a black hole?

AI Thread Summary
The discussion centers on the mass of black holes, specifically questioning whether there is a maximum mass limit. It is clarified that while calculations of black hole mass can be complex and often miscalculated using Newtonian physics, there is no theoretical maximum mass for a black hole beyond the total mass-energy of the observable universe. The importance of using accurate methods, such as general relativity and considering the gravitational effects of surrounding matter, is emphasized for accurate mass determination. The conversation also touches on the nature of black holes, including the event horizon and the behavior of matter within it, suggesting that the understanding of black holes remains incomplete. Overall, the dialogue illustrates the complexities of black hole physics and the ongoing exploration of their properties.
  • #51
Also there must be significant energy driving this flat rotation. A slow moving dark matter/energy would not be enough so the speed must be significant and at a universal constant speed. What this speed is is yet to be determined, but can be calculated based on the force needed to maintain the rotational velocity.
 
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  • #52
Hubble, dark matter is not driving expansion. Expansion is *possibly* being accelerated by dark energy. Although I think I remember some talk about how dark energy isn't necessary since we already have the cosmological constant or something.

Dark matter is also not causing galaxies to rotate. What it does is provide extra gravity to hold the outside areas of the galaxies together and allow the matter there to orbit the galactic center at a speed that would be too quick otherwise. Dark matter forms a spherical "halo" around the galaxy where it spends most of its time.
 
  • #53
Drakkith said:
Hubble, dark matter is not driving expansion. Expansion is *possibly* being accelerated by dark energy. Although I think I remember some talk about how dark energy isn't necessary since we already have the cosmological constant or something.

Dark matter is also not causing galaxies to rotate. What it does is provide extra gravity to hold the outside areas of the galaxies together and allow the matter there to orbit the galactic center at a speed that would be too quick otherwise. Dark matter forms a spherical "halo" around the galaxy where it spends most of its time.

But surely a stationary halo of dark matter would impede the rotation. As I said before finding things happen before expected, As in the rotation being faster than expected implies a force not yet described. Take e-mc2. If we have e=m(c+n)2 then we not only have a unit of length that has been stretched but also a gain in energy and speed faster than light, but what is n? It is believed that dark matter is increasing or am I wrong?
 
  • #54
hubble_bubble said:
But surely a stationary halo of dark matter would impede the rotation. As I said before finding things happen before expected, As in the rotation being faster than expected implies a force not yet described.

How would it impede the rotation? Dark matter does not interact with normal matter through any force other than gravity. It can pass right through normal matter unimpeded.

Take e-mc2. If we have e=m(c+n)2 then we not only have a unit of length that has been stretched but also a gain in energy and speed faster than light, but what is n? It is believed that dark matter is increasing or am I wrong?

What are you talking about? The unit c is not a unit of length, but of velocity. I have absolutely no idea what you are trying to get across. You can't just insert new things into equations like this. Nor do I know what n is, as dark matter is not increasing.
 
  • #55
We have the Schwarzschild radius rs = 2GM/c2. We also have the detected dark matter halo. Is the distance from the halo proportional to the size of the galactic black hole and its radius? Has anyone calculated this? If there is no relationship then I would agree that there is no connection. At first it was thought that Galaxy M33 had no central black hole but it is just small in comparison. It does have a halo. If there is a relationship between the black hole and the halo and this is proportional then this could be similar to the Schwarzschild radius only further out.

I don't know if this has been confirmed .

http://www.guardian.co.uk/science/2011/sep/22/faster-than-light-particles-neutrinos

Aren't neutrinos considered a type of dark matter.
 
  • #56
Maybe the n in e=m(c+n)2 stands for neutrino
 
  • #57
Does the percentage increase found at Gran Sasso tie in in any way with the rate of expansion found for the universe?
 
  • #58
Drakkith said:
How would it impede the rotation? Dark matter does not interact with normal matter through any force other than gravity. It can pass right through normal matter unimpeded.

How do you know there is no interaction between matter and dark matter?
 
  • #59
hubble_bubble said:
I don't know if this has been confirmed .

http://www.guardian.co.uk/science/2011/sep/22/faster-than-light-particles-neutrinos

Aren't neutrinos considered a type of dark matter.

Neutrinos do not travel FTL. There was an error in the setup of the detectors and clocks. I believe one of the cables was incorrectly installed. And while neutrinos may be a type of dark matter, they are not the type that we normaly talk about if my memory is correct.

hubble_bubble said:
Maybe the n in e=m(c+n)2 stands for neutrino

Are you making this up or did you get this from somewhere?

hubble_bubble said:
Does the percentage increase found at Gran Sasso tie in in any way with the rate of expansion found for the universe?

No, that was a faulty experiment.

hubble_bubble said:
How do you know there is no interaction between matter and dark matter?

Observations have been made and we have reason to believe that dark matter doesn't interact with normal matter. Look at the Bullet Cluster for example.
 
  • #60
hubble_bubble said:
Aren't neutrinos considered a type of dark matter.

Indeed they are, but they fall under the subcategory of 'hot' dark matter, whereas most of what we're looking for is 'cold' dark matter. Google around if you want to know more about the distinction.
 
  • #61
Drakkith said:
Neutrinos do not travel FTL. There was an error in the setup of the detectors and clocks. I believe one of the cables was incorrectly installed. And while neutrinos may be a type of dark matter, they are not the type that we normaly talk about if my memory is correct.



Are you making this up or did you get this from somewhere?



No, that was a faulty experiment.



Observations have been made and we have reason to believe that dark matter doesn't interact with normal matter. Look at the Bullet Cluster for example.

Sorry the neutrino thing was a joke too good to miss. The bullet cluster article raises some issues. As MACS J0025.4-1222 appears to have had its dark matter halo stripped it would be useful to observe effects on rotational velocity if any. Also if this halo reforms over time then the dark matter has to come from somewhere. Also what about the galaxy rotation problem?
 
  • #62
hubble_bubble said:
Sorry the neutrino thing was a joke too good to miss.

I think you should work on your delivery.

The bullet cluster article raises some issues. As MACS J0025.4-1222 appears to have had its dark matter halo stripped it would be useful to observe effects on rotational velocity if any. Also if this halo reforms over time then the dark matter has to come from somewhere.

The dark matter would come from already existing dark matter.

Also what about the galaxy rotation problem?

What about it?
 
  • #64
My god not a direct connection between dark matter halos and black holes! Whatever next?
 
  • #65
hubble_bubble said:
This is VERY interesting. Go figure.

http://www.nasa.gov/mission_pages/chandra/news/H-12-191.html

I don't see what this has to do with the rest of the thread. Please don't post just to post, it doesn't help the thread at all and will only make for a confusing conversation with multiple topics being discussed at one time.
 
  • #66
Drakkith said:
I don't see what this has to do with the rest of the thread. Please don't post just to post, it doesn't help the thread at all and will only make for a confusing conversation with multiple topics being discussed at one time.

Well the original thread asked was there a maximum mass for a black hole. The article in the link brings into question how that mass is derived. It also implies that the dark matter halo inhabits a specific region around a black hole. So I think it should be considered pertinent to the thread topic. If the halo is proportional to the mass of the black hole then detecting the size of a galactic halo should allow calculation of the expected mass at the galactic centre.
 
  • #67
Also bear in mind that the halo is proportional to the size of black hole and not the mass of the galaxy it surrounds.
 
  • #68
If we have rs=2Gm/c2 as our Swarzchild radius then rs+n1 could be the lower bound of the halo and rs+n2 could be the upper bound. The gravitational constant and mass have to remain the same. To derive these new values then surely c must change under the conditions within and surrounding a black hole when considering dark matter. In fact I was wrong. c has to decrease in order to provide the range for n1 and n2. This is the ultimate result from light falling into the event horizon. The consequence of this would be a projected region of a proportional size to the mass of the black hole that would effectively trap the dark matter unless some galactic collision were to strip it away.
 
  • #69
Does anyone know if there are any detections of waves from around a black hole and what frequency range they are at?
 
  • #70
hubble_bubble said:
Also bear in mind that the halo is proportional to the size of black hole and not the mass of the galaxy it surrounds.
There is no known link between dark matter and black hole mass [re: Supermassive black holes do not correlate with dark matter halos of galaxies http://arxiv.org/abs/1101.4650] . It is also unlikely dark matter is a significant contributor to black hole mass because, unlike baryonic matter, it is essentially collisionless. Baryonic matter is slowed by collisions with other baryonic matter allowing it to shed angular moment and be captured by local gravitational wells [like black holes]. Ingesting large amounts of dark matter would also interfere with galaxy formation via a process called runaway accretion.
 
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  • #72
Chronos said:
There is no known link between dark matter and black hole mass [re: Supermassive black holes do not correlate with dark matter halos of galaxies http://arxiv.org/abs/1101.4650] . It is also unlikely dark matter is a significant contributor to black hole mass because, unlike baryonic matter, it is essentially collisionless. Baryonic matter is slowed by collisions with other baryonic matter allowing it to shed angular moment and be captured by local gravitational wells [like black holes]. Ingesting large amounts of dark matter would also interfere with galaxy formation via a process called runaway accretion.

I'll get back to you on that I have just had some very interesting thoughts.
 
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  • #73
"We conclude that black holes do not correlate directly with dark matter. They do not correlate with galaxy disks, either. Therefore black holes coevolve only with bulges."

This implies rotational velocity as the bulge will form around a rotating black hole, presumably with significant velocity. Also accumulating an ergosphere where time and space behave in peculiar ways.
 
  • #74
Chronos said:
There is no known link between dark matter and black hole mass [re: Supermassive black holes do not correlate with dark matter halos of galaxies http://arxiv.org/abs/1101.4650] . It is also unlikely dark matter is a significant contributor to black hole mass because, unlike baryonic matter, it is essentially collisionless. Baryonic matter is slowed by collisions with other baryonic matter allowing it to shed angular moment and be captured by local gravitational wells [like black holes]. Ingesting large amounts of dark matter would also interfere with galaxy formation via a process called runaway accretion.

One definite link is that dark matter does not cluster near a black hole. This would distort the galaxy it inhabits. I see your point though. They do say that it is "unless they contain a bulge". In this scenario the correlation has to be explained somehow.

Just a follow up I do not believe that the dark matter contributes to the mass of a black hole. I am just trying to work out how they are linked under certain conditions.
 
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  • #75
just one fly in the ointment. If the event horizon stops anything at light speed or less escape the black hole how does gravity itself have an influence outside the EH. It travels at the sped of light. I know that this sounds like a very silly question to ask as it is self referencing, but that is a force that travels at the speed of light that violates its own bounds. We do not even know what gravity is but there could be a case for arguing that is should trap everything including itself.
 
  • #76
hubble_bubble said:
I have just looked up this article about quantum gravity.

http://www.sciencedaily.com/releases/2001/02/010212075309.htm

If the speed of light is frequency dependent then this could explain the position of the halo.

Since that article is over 11 years old and I've never heard of this before, I'm going to assume that no correlation has been observed yet. Nor do I understand how this could possibly explain the position of the halo.

hubble_bubble said:
"We conclude that black holes do not correlate directly with dark matter. They do not correlate with galaxy disks, either. Therefore black holes coevolve only with bulges."

This implies rotational velocity as the bulge will form around a rotating black hole, presumably with significant velocity. Also accumulating an ergosphere where time and space behave in peculiar ways.

I really don't think the rotation of the black hole has anything to do with the velocity of the bulge. The effect of the black hole's rotation just doesn't extend far enough out to do anything like this to my knowledge.

hubble_bubble said:
just one fly in the ointment. If the event horizon stops anything at light speed or less escape the black hole how does gravity itself have an influence outside the EH. It travels at the sped of light. I know that this sounds like a very silly question to ask as it is self referencing, but that is a force that travels at the speed of light that violates its own bounds. We do not even know what gravity is but there could be a case for arguing that is should trap everything including itself.

Gravity is in the geometry of spacetime, it is not something that has to "get out" of anything. Gravity WAVES travel at the speed of light, but gravity, meaning the geometry of spacetime, acts instantly. It is only the change in spacetime that moves at c.
 
  • #77
See http://curious.astro.cornell.edu/question.php?number=264/
 
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  • #78
Chronos said:
See http://curious.astro.cornell.edu/question.php?number=264/

Thanks for the link. Interesting.
 
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  • #79
Drakkith said:
Since that article is over 11 years old and I've never heard of this before, I'm going to assume that no correlation has been observed yet. Nor do I understand how this could possibly explain the position of the halo.



I really don't think the rotation of the black hole has anything to do with the velocity of the bulge. The effect of the black hole's rotation just doesn't extend far enough out to do anything like this to my knowledge.



Gravity is in the geometry of spacetime, it is not something that has to "get out" of anything. Gravity WAVES travel at the speed of light, but gravity, meaning the geometry of spacetime, acts instantly. It is only the change in spacetime that moves at c.

I take your points. I have to say though that the prograde and retrograde photon orbits have set distances that can be calculated for a Scwarzchild black hole. For Kerr black holes the spherical orbits can also be described. These distances are proportional. Why then can this not extend further. We have gravity amplification in effect and an enormous mass. Since theoretically gravity extends to infinity the diminishing force has a curve plotted against mass and distance. In the normal universe outside the event horizon I would expect this to behave differently than when a black hole is involved.
 
  • #80
You can extend it further. It just has negligible effect due to the vast distances between objects in space. And I don't know what you mean by "gravity amplification", as such a thing does not exist. Gravity behaves no differently near a black hole than it does near any other object.
 
  • #82
Drakkith said:
You can extend it further. It just has negligible effect due to the vast distances between objects in space. And I don't know what you mean by "gravity amplification", as such a thing does not exist. Gravity behaves no differently near a black hole than it does near any other object.

Within the event horizon I would say that gravity is definitely amplified. Past the point of no return. BTW what mass would produce a Swarzchild radius equal to the Planck length and also to Planck length cubed?
 
  • #84
hubble_bubble said:
Within the event horizon I would say that gravity is definitely amplified. Past the point of no return. BTW what mass would produce a Swarzchild radius equal to the Planck length and also to Planck length cubed?

Then you are incorrect. Gravity is not amplified within the event horizon according to current theory.
 
  • #85
Drakkith said:
Then you are incorrect. Gravity is not amplified within the event horizon according to current theory.

If you study the article in the link in #83 then this is what happens. Also mass is increased as if out of nowhere which is what I had found and didn't believe. This research ties cold dark matter to black holes.
 
  • #86
hubble_bubble said:
BTW what mass would produce a Swarzchild radius equal to the Planck length and also to Planck length cubed?
Simple: the Planck mass. Or maybe the Planck mass with a small prefactor, as those are arbitrary anyway.
 
  • #87
Have you looked at the work on Sagittarius A* where the milky way supermassive black hole is assumed to be located and also the work on dark matter detection in the milky way that has found NO evidence of halo effects? If the halo is in fact made up partly of primordial black holes then we are looking in the wrong direction completely.
 
  • #88
mfb said:
Simple: the Planck mass. Or maybe the Planck mass with a small prefactor, as those are arbitrary anyway.

I need a cubed component for my calculations but it needs to relate to this Planck mass. I am not sure if this is simply the Planck volume. If it is then this ties in with quantum effects but what happens when this is scaled up?
 
  • #89
If we assume that matter at the singularity is contained within the Planck volume then plotting back from the Schwarzschild radius the escape velocity may well approach infinity. I need to think about that one.
 
  • #90
To account for this violation of relativity time must speed up and the mass is effectively thrown forward into the future. Time does not go backwards so bad news for time travel.
 
  • #91
hubble_bubble said:
If you study the article in the link in #83 then this is what happens. Also mass is increased as if out of nowhere which is what I had found and didn't believe. This research ties cold dark matter to black holes.

This has nothing to do with gravity itself, but only on our way of calculating its effects in the domain of very high gravitational force. The apparent increase is based against Newtonian gravity which is already known to be incorrect, but since it is MUCH easier to use than General Relativity it is the choice for most calculations. As the paper shows it ceases to be accurate in regions of very high mass. Interestingly they say that their equation accurately predicts gravity using a constant factor.
 
  • #92
I am now in the position where time could flow either forwards or backwards with a swap of the functions of space and time into what could be termed timespace. Going backwards would increase the mass of the universe and have the same energy and mass existing twice which I really don't believe. Moving forward would make more sense. Lorentz transforms of spacetime into timespace would have to modify beta, t and x at least. Whether this would even be possible I don't know. Even worse this is using the standard configuration. There would also need to be movement of the singularity through a stretched timespace as mass increases. This would need to be proportional to the Schwarzschild radius somehow although who knows how you compute this.

The forward moving mass would only be partially present at any spacetime point in the external universe and mass would seem less than expected. Yet at some future time this mass will resolve itself and again become "available" I think.
 
  • #94
The relationship of the frame dragging should be described by the relationship 2lp/tp where tp = Planck time and lp = Planck length. If anyone disagrees or thinks I am too off the wall please let me know.
 
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  • #95
Closed pending moderation.
 

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