what is black hole made out of and what does a black hole "experience"?

[Aki]

I've always wondered if it is possible for a black hole to suck up another black hole, or if a black hole could eventually suck up the whole universe.

[Tormod]

In the book, "The Five Ages of the Universe", the authors speculate that over the unimaginably long time-span left in the universe, there will come an era where there is basically only black holes in the universe. And even these will evaporate into nothing.

Read my review of it here:
http://www.hypography.com/article.cfm?id=29590

[Tormod]

I wrote up a hypography on black holes a few years back. It seems most of the links are still valid:

Inside Black Holes
http://www.hypography.com/topics/insideblackholes.cfm

BTW, I do not believe that the laws of physics break down. However, since we are unable to look inside a black hole (as of yet) there is really no way we can know. But while Hawking's recent "retraction" of his "nothing escapes a black hole" theory is interesting, it is important to keep in mind that it is still just a theory.

[BlameTheEx]

Tormod

The laws of physics don't break down?

Consider. At the surface of the singularity the escape velocity is C. That means that a body simply dropped will reach C at that point (infinite energy), and carry on accelerating (more than infinite energy).

Nor can you argue that it didn't count, as it happens only where we will never know. Consider the case of a body that is not passively dropped, but starts with a velocity towards the Black Hole. It will reach C quicker - before it reaches the surface of the singularity. Infinite energy in normal space!

No. I don't believe that the laws of physics break down ether - which is why I am not a fan of Black Holes.

[Tormod]

I don't understand a single thing of your last post, Blame. Does a singularity have a surface? And how can it have an escape velocity of c? That would mean that all light would get away easily.

[Tim_Lou]

hmm, i got an idea, if the photons are trapped in a black hole, does it mean that it is converted into mass?

i read some article online before, it says that the way we detect black hole is some "vitrual photons" that are created and travelled faster than the speed of light and ultimately reached us... is that right or?

[Tormod]

Originally posted by: Tim_Lou
hmm, i got an idea, if the photons are trapped in a black hole, does it mean that it is converted into mass?

Interesting question. I have no idea though.

i read some article online before, it says that the way we detect black hole is some "vitrual photons" that are created and travelled faster than the speed of light and ultimately reached us... is that right or?

No, I'd say that is in violation of the laws of physics. Whether physics breaks down inside a black hole or not, they certainly don't outside of it (AFAIK).

[Aki]

Originally posted by: Tim_Lou
i read some article online before, it says that the way we detect black hole is some "vitrual photons" that are created and travelled faster than the speed of light and ultimately reached us... is that right or?

I think you might be thinking about the anti-particles. Hawking said that every particle has an anti-particle, which once both come in contact, they will annihilate. He said that while the particle gets sucked into the black hole, its anti-particle might escape, and therefore, it looks like as if the black hole is emitting these ani-particles.

[BlameTheEx]

Tormod

You caught me using ambiguous language again.

Ok. It is doubtful that a Black hole has a surface, but Singularity is a slightly different term. It defines an area of space outside normal laws, or so I have always taken the term. As applied to Black Holes, it defines the point of no return. In effect it is a sphere, and so it has a surface, although not the sort you walk on. It is more a concept than an actuality.

If such a thing is possible, NOTHING can escape from a body with an escape velocity of C. You might argue that a photon could, as it has a velocity of C, but ALL its energy would be lost in the escape. A photon with no energy simply does not exist.

The argument for Black Holes goes that although particles are apparently accelerated to greater than C within the Singularity, it does not count, as the inside of a Singularity is not part of the universe.

[Aki]

Originally posted by: BlameTheEx

If such a thing is possible, NOTHING can escape from a body with an escape velocity of C. You might argue that a photon could, as it has a velocity of C, but ALL its energy would be lost in the escape.

wouldn't the escape velocity be greater than C?