# Thread: The Anatomy Of A Black Hole

1. Originally Posted by EcK
for the love of shiva, would people stop confusing infinite energy and density tending to infinity.

Ever heard of the resolution for zeno's paradox ?
well an arrow can infinitely tend to some end destination, but the total volume/surface/length is still finite.
Doesn't it take infinite energy to create this:

I was told that there isn't enough energy in the universe to make it happen. I figured that the energy of a blackhole would be related to the density or something. What does zeno's arrow paradox have to do with this? :confused:

2. Originally Posted by King-Of-Despair
Doesn't it take infinite energy to create this:

I was told that there isn't enough energy in the universe to make it happen. I figured that the energy of a blackhole would be related to the density or something. What does zeno's arrow paradox have to do with this? :confused:
Oh sure, some say that'd take more energy than available in the universe, then again it all depends on the scales. But yeah, it would be pretty hard to create 'space travel ready wormholes' even without the whole issue of extreme gravity differencials (and the smaller the radius of the black hole the wilder the differencials)
You could speculate that with a smart repartition of mass in space you could pass through such a wormhole in constant freefall at a constantly growing speed, then the mass would make you decelerate as you'd climb the gravitational well on the other side.

I still don't see why it would take 'infinite' energy. As long as you accept that there's causality, it means that there's an absolute limit for information transmission. If you accept that this limit is 'the speed of light' then it also means that there's a minimum scale at which energy can be expressed (i guess you could argue that to a degree but well)
So true 'infinite' density of energy cannot be reached.

3. Highly simplified and romanticized [like Eck said, the last two theories are crap, and any science teacher knows this] but effective in presenting the general idea.

4. Originally Posted by JocktheMotie
Highly simplified and romanticized [like Eck said, the last two theories are crap, and any science teacher knows this] but effective in presenting the general idea.
The second to last 'theory' (they're more like ideas) was probably saying that as you enter the black hole, you'll be dialated, which stretches you out, creating heat, which is hot enough to emit X-Rays/Gamma Rays. But that doesn't happen beyond the point where light cannot escape (Schwartzchild Radius), and I'm pretty sure that emits rays in all directions. They said the ship would disintegrate and eject particles out the other side

The last theory wasn't crap, it's not entirely impossible... I think

5. Originally Posted by King-Of-Despair
The second to last 'theory' (they're more like ideas) was probably saying that as you enter the black hole, you'll be dialated, which stretches you out, creating heat, which is hot enough to emit X-Rays/Gamma Rays. But that doesn't happen beyond the point where light cannot escape (Schwartzchild Radius), and I'm pretty sure that emits rays in all directions. They said the ship would disintegrate and eject particles out the other side

The last theory wasn't crap, it's not entirely impossible... I think
Black holes don't emit anything outside of hawking radiation, which is still theoretical at this point and has never been observed. You do not get "blasted out the other side" simply because black holes are a closed system and *nothing* escapes. The x-rays are, like you said, emitted as matter falls into the black hole, not the black hole itself.

I don't really know where they got the idea that you get ejected in tiny pieces out the other side. Otherwise it's not a black hole.

IMO, the most interesting things about black holes are that you only need it's surface area to describe the black hole's content and that their properties are equal to that of subatomic particles in that they have a charge, mass, and angular momentum and are indistinguishable from each other if those values match up. It's like a super-particle.

6. God that is amazing.

"Singularity -- the center of a black whole where matter is infinitely dense and gravity is infinitely strong and space and time as we know them cease to exist"

7. Black holes aren't infinitely dense according to string theory.

8. Its-a like-a speghetti; they'mak'a'da pasta and they tossa and turna and squisha togetha until you hav'a stringy de meatball. *kisses fingers* Magnifico.

9. Originally Posted by JocktheMotie
You do not get "blasted out the other side" simply because black holes are a closed system and *nothing* escapes. The x-rays are, like you said, emitted as matter falls into the black hole, not the black hole itself.

I don't really know where they got the idea that you get ejected in tiny pieces out the other side. Otherwise it's not a black hole.
This stemmed from equations done that predicted there were really two regions of spacetime connected with the black hole. One region was said to be out universe, and the other said to be another universe connected through a wormhole. There would also be a white hole in the "past" section of the Schwarzschild geometry. The entire object is really a "grey-hole".

You can see the process at arriving at this conclusion here:
Schwarzschild Geometry
http://www.math.ksu.edu/~westmore/Pe...agramsTALK.pdf
Transition from Schwarzchild single-universe view of black hole to Kruskal-Szekeres two-universe view:
http://www.jessemazer.com/images/p835Gravitation.jpg

10. This is probably a stupid question. But uhhhh what is gravity?

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