Black Holes .

Status
Not open for further replies.
paddoboy said:
Correct. There is no reason why BH's are not partly or completely made of DM.
Click to expand...
No. They re not made of any "type" of matter.

Per post 112:
This is what is meant by "black holes have no hair". Black holes can be completely characterized by only three externally observable classical parameters: mass, electric charge, and angular momentum. It is meaningless to ask "what kind of matter makes up a black hole".
 
river said:
A singularity is a purely mathematical construct .
Click to expand...

Sure. Whatever is at the centre of a black hole, our current math does not describe it. We call that the singularity.

And there is no reason to think it might have a tunnel to anywhere.
 
DaveC426913 said:
No. They re not made of any type of matter.

Per post 112:
This is what is meant by "black holes have no hair". Black holes can be completely characterized by only three externally observable classical parameters: mass, electric charge, and angular momentum. It is meaningless to ask "what kind of matter makes up a black hole".
Click to expand...

Disagree

The Black Hole is the essence of all galaxies .
 
river said:
Mathematics didn't include the physical .
Click to expand...
This statement is meaningless.

The black hole, being spherical, has a centre point. That's simple geometry.
We do not have a theory about what happens there, since it involves gravitational pressure beyond what GR covers, so its physics is unknown.

But there is no reason to suppose there is a "tunnel to somewhere else" there any more than there is reason to suppose there is a tiny unicorn there.
 
DaveC426913 said:
This is a bit leading. There is no reason to suppose that the singularity of a black hole leads somewhere. It's not actually a hole.
Click to expand...
Well, yes I agree..That was put rather poorly, and I did think he was referring to a singularity as defined by infinite curvature and density. That definition and the infinite density and curvatures, has been generally rejected now
DaveC426913 said:
No. They re not made of any "type" of matter.

Per post 112:
This is what is meant by "black holes have no hair". Black holes can be completely characterized by only three externally observable classical parameters: mass, electric charge, and angular momentum. It is meaningless to ask "what kind of matter makes up a black hole".
Click to expand...
Hmmm. I am certainly familiar with the "no hair" concept and the three parameters that can be used to describe a BH, mass, charge and angular momentum. But nothing can stop a BH from swallowing DM I would have thought. It may certainly react different to baryonic matter, in that baryonic matter will heat up and radiates light...not so with DM. Are we on the wrong page?
https://www.space.com/8080-black-holes-gobble-dark-matter.html
 
DaveC426913 said:
The type of mass that originally formed the black hole might have been normal matter, dark matter, antimatter or energy. (Most of them are formed from normal matter). Once the mass had fallen in though, the matter loses its identity, and that information can never be recovered.
Click to expand...
BINGO!!! That is what I was trying to say!!! No excuses other then my footy team is playing and its difficult to type and watch TV together. :p
 
paddoboy said:
But nothing can stop a BH from swallowing DM I would have thought
Click to expand...
Agree.

My point is, once DM falls into the BH, it loses its identity. Same with any other type of matter. The information about what kind of matter it was before it fell in is gone from the universe forever.

That is why river's question 'what kind of matter is a BH made of' makes no sense. A BH is not "made of" any kind of matter; it is only mass (and charge and spin).
 
river said:
Disagree

The Black Hole is the essence of all galaxies .
Click to expand...
Most elliptical galaxies do not have black holes at their centres.
ellipt3.jpg
 
paddoboy said:
Well, yes I agree..That was put rather poorly, and I did think he was referring to a singularity as defined by infinite curvature and density. That definition and the infinite density and curvatures, has been generally rejected now

Hmmm. I am certainly familiar with the "no hair" concept and the three parameters that can be used to describe a BH, mass, charge and angular momentum. But nothing can stop a BH from swallowing DM I would have thought. It may certainly react different to baryonic matter, in that baryonic matter will heat up and radiates light...not so with DM. Are we on the wrong page?
https://www.space.com/8080-black-holes-gobble-dark-matter.html
Click to expand...

And Space .
 
river said:
Upon what form of matter is the BH based ? I keep asking this question , no answer .
Click to expand...
You've been answered many times. I previously gave you an answer.

I told you that black holes form from collapsing stars. So, those black holes are "based on" star-stuff - their mass is the mass of all that hydogen and helium and stuff that fell in.
 
James R said:
You've been answered many times. I previously gave you an answer.

I told you that black holes form from collapsing stars. So, those black holes are "based on" star-stuff - their mass is the mass of all that hydogen and helium and stuff that fell in.
Click to expand...
I am trying to avoid giving river the impression that black holes are "made" of matter. They're not.
Anything that falls into a black hole (normal matter, dark matter, antimatter, etc.) loses its identity forever. A black hole does not contain matter; it only contains mass (and charge and spin).
 
Status
Not open for further replies.
Back
Top