Black Holes .

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davewhite04 said:
Dark matter or matter, take your pick.
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davewhite04 said:
How can a black hole be formed by matter, originally.
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Simply through gravitational collapse after a star uses up its available fuel.
[1] When a star exhausts all its available fuel, we have three possible results, depending on the mass of the star...[a] Stars around our own Sun's size, end up as White Dwarfs...incredibly dense degenerate matter held up from further collapse by EDP [Electron Degeneracy Pressure] Larger mass stars are able to overcome EDP but are held up by further collapse by NDP [Neutron Degeneracy Pressure] [c] The largest of the stars at the end of their lives, are able to overcome even the NDP and form BH's.

[2] When the collapse reaches the Schwarzchild radius of any given mass, further collapse is compulsory, and so the mass collapses to a singularity.
And of course the recent 14 discoveries of colliding BH pairs, and even more recently the EHT photo of a BH, or more correctly the BH shadow.

Just a friendly note of warning, I would not really take too much notice of river and his trolling and feigning ignorance. He has been informed of this many many times, but prefers the excitement of the unscientific supernatural and paranormal nonsensical world. That is why he has been banned from the science sections. Sad but true.
 
paddoboy said:
Simply through gravitational collapse after a star uses up its available fuel.
[1] When a star exhausts all its available fuel, we have three possible results, depending on the mass of the star...[a] Stars around our own Sun's size, end up as White Dwarfs...incredibly dense degenerate matter held up from further collapse by EDP [Electron Degeneracy Pressure] Larger mass stars are able to overcome EDP but are held up by further collapse by NDP [Neutron Degeneracy Pressure] [c] The largest of the stars at the end of their lives, are able to overcome even the NDP and form BH's.

[2] When the collapse reaches the Schwarzchild radius of any given mass, further collapse is compulsory, and so the mass collapses to a singularity.
And of course the recent 14 discoveries of colliding BH pairs, and even more recently the EHT photo of a BH, or more correctly the BH shadow.

Just a friendly note of warning, I would not really take too much notice of river and his trolling and feigning ignorance. He has been informed of this many many times, but prefers the excitement of the unscientific supernatural and paranormal nonsensical world. That is why he has been banned from the science sections. Sad but true.
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Where's the other end of a black hole?
 
river said:
All galaxies have a black hole at its center .
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No they don't.

river said:
Upon what form of matter is the BH based ? I keep asking this question , no answer .
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You have gotten the answer; you just don't understand it.

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.

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".
 
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davewhite04 said:
Where's the other end of a black hole?
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Good question...the answer we don't know. Nothing at all is known about the true nature inside the EH, other then trusting GR [which has a good track record] which tells us that once any matter collapses to its Schwarzchild radius [equal to the EH] then nothing can stop further collapse. But GR itself fails us at the quantum/planck level, and most scientists reject a singularity as defined by infinite spacetime curvature and density. This means that a surface of sorts exists at or just below that level.

Also the concept of a BH was first hypothesised with Newtonian mechanics by a bloke called John Michell. This was called a "Dark Star"with a probable surface at the EH, where the escape velocity equals "c". GR at that time and the compulsory collapse and the Schwarzchild limit was unknown.
 
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