# Black Holes .

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OK.

You need - what? 15 minutes to compose your thoughts? No prob.

You will

What above ?

Dark matter or matter, take your pick.
Correct. There is no reason why BH's are not partly or completely made of DM.

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.

A singularity is a purely mathematical construct .

Correct. There is no reason why BH's are not partly or completely made of DM.
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".

A singularity is a purely mathematical construct .

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.

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".

Disagree

The Black Hole is the essence of all galaxies .

You can disagree all you like; it doesn't add credence to your unfounded ideas. Put down the UFO book and pick up a basic science book.

The Black Hole is the essence of all galaxies .
What does this statement have to do with anything?
I mean, it's wrong, but why even mention it?

river said:
A singularity is a purely mathematical construct .

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.

But here is the thing ;

Mathematics didn't include the physical .

Mathematics didn't include the physical .
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.

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.
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
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".
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

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.
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.

But nothing can stop a BH from swallowing DM I would have thought
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).

Disagree

The Black Hole is the essence of all galaxies .
Most elliptical galaxies do not have black holes at their centres.

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

And Space .

Most elliptical galaxies do not have black holes at their centres.

Why not ?

Upon what form of matter is the BH based ? I keep asking this question , no 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.

Why not ?
Because your assumption, below, is faulty:
The Black Hole is the essence of all galaxies .

Black holes are not the essence of all galaxies.