Thread: what is a black hole

What is a black hole? How does it differ from the perspective of relativity vs quantum mechanics vs string theory vs holographic theory? What is a black hole?

In simple terms as most are familiar with, a black hole is a region in space where the energy/matter is concentrated so much that space time is warped back on itself. Thats the relativity view, in layman's the mass is sufficiently concentrated that the escape velocity to over come the gravity from this mass is greater than the speed of light. Thus even light can't escape, hence the term "black hole".

Ok I know you are perfectly aware of all this and I know from your question you are seeking the finner details from each current mainstream theories. But all we can do is speculate on what we do know. And the bottom line is we don't know what black holes are, what they look like and what really happens at the centre of one.

That sounds like a song.
"What is a Black Hole" is the chorus... Tom and his ditty... Seriously, I think I'm going to shove you into one.
Could you ever ask a question that doesn't require a person to have supermassive knowledge? Really, who on this little forum knows enough about Relativity, String, holographic AND QM to put forth an intelligent response?

Wait- to all of them- it appears black.


That didn't work did it?

Ok, fine.

Well- off the head- String theory is not really a theory. It's a hypothesis. Same as holographic. They do not deal with black holes...
But the Same Math is used, whether you are talking string, QM or Relativity.
So you run into the same problems, numbers crunching into absurdities and infinities and just over-all, failing to cooperate.

I think the most interesting perspective will be QM after development of about a thousand years. Perhaps a little more...

To answer your question I would require a level of mathematical competence I do not have...

but the fundamental question is already answered and I also suspect you knew all this already...

A solar mass greater than our sun is required and determination of the cut off mass is calculable...

That at some point a large mass star having converted the available mater to another is approaching the end of its balanced life.

As the expulsion of energies falls below a balance so a collapse begins... and the Black Hole is born..

Where the mass is greater than escape velocity the space time is so bent as to prohibit escape..

As we can not look into or otherwise test these findings a knowledge of nuclear physics is required to understand the mechanics of the BH.

Can we with any assumption confirm and know what is the state of mater at the hart of the BH. NO.

Its hot, dense, and no place to get out of....

As for questions of quantum or strings and other unknowns...

I have no idea.. but doubt the reality of such.

Originally Posted by astromark

To answer your question I would require a level of mathematical competence I do not have...



A solar mass greater than our sun is required and determination of the cut off mass is calculable...

This is a Stellar Black Hole and needs a sun of about 20 Sol masses.
A big puppy, but nowhere near as big as the biggest dog on the block so far...

Originally Posted by astromark

That at some point a large mass star having converted the available mater to another is approaching the end of its balanced life.
As the expulsion of energies falls below a balance so a collapse begins... and the Black Hole is born..

It's harder to generate fusion with the heaver elements. Soon, the star begins to collapse under its own weight.

Originally Posted by astromark

Where the mass is greater than escape velocity the space time is so bent as to prohibit escape..

And here is General Relativity.
GR describes spacetime as warped by mass.
Using Einsteins field equations, Karl Schwarzchild calculated a gravitational spherical body of point mass. The humble beginnings of pondering whether such a thing could exist. It was later dubbed a "black hole."
Stephen Hawking employed reasoning in Quantum Mechanics to consider that black holes must radiate. Hawking Radiation, supposedly, can cause a black hole to evaporate completely away... but that would probably take more time to do than there is left for the Universe to exist. If we're looking at a Crunch, anyway. If it continues to just cool and expand, there will be plenty of time- But no one is likely to be around to see it. Or much of anything else, for that matter.
Most all observation of black hole evidence is done using GR. This is primarily GR's baby.
Without a good and solid working Theory of Quantum Gravity, sadly, QM must wait at GR's side for its turn at the Black Hole enigma. But when it gets its turn, it will likely take over as a good instructor takes an eighteen year old off his parents hands to enhance his knowledge.
It probably will not happen in our lifetimes... maybe...

Sting Theory...
Ugh...

String Proponents like to use black holes as evidence that Sting can unify QM and Relativity.
According to String, black holes are filled with strings and provide a "no information lost" property to black holes.

Astromark- You may not be "competent in mathematics" ( I Know I'm not!) but you're definitely competent and I am glad you're around.

Originally Posted by David M W

And the bottom line is we don't know what black holes are, what they look like and what really happens at the centre of one.

Are you sure? <--- Link

Originally Posted by mugaliens

Are you sure? <--- Link

Nice link Mugs!

Still this is only in theory, we really can't know for sure until we find a way to observe or extract data from inside the event horizon.

Originally Posted by David M W

Nice link Mugs!

Still this is only in theory, we really can't know for sure until we find a way to observe or extract data from inside the event horizon.

I believe that as research in particle physics continues to progress, the math and science in that field will develop to the point where we can know with near absolute certainty what's going on inside a black hole.

Yes the work of Thomas Lucas and Dave Brody is worth a look at... and well presented.

I noticed the copy right note 2009.. I think they would approve of us viewing this.. No doubt.

I am sorry that even after viewing and digestion of that there is still the voice of 'David M W.' suggesting we are still not sure..

I can not speak for the rest of you.. but I am receptive of this information as facts as best we can know at this time.. and note,

Elsewhere in these forums I saw a remark that suggested we the scientific community were religiously bound to our view..

I find that as insulting and unfair. As the true scientist is always willing to throw out the baby with the bath water..

As facts are found so too does the view change. That is if understood the truly only scientific way forward.. >>>> and forward we go.

Originally Posted by mugaliens

I believe that as research in particle physics continues to progress, the math and science in that field will develop to the point where we can know with near absolute certainty what's going on inside a black hole.

I hope this to be true, and find it an exciting prospect!