Warp wrote:
>> Not true. They just won't guess what happens at the singularity. It's 
>> called a singularity because the math breaks down there.
> 
>   No, I think it's inside the event horizon. While GR equations tell us
> what happens if GR holds inside the event horizon in the same way as
> outside it, it's still speculation.

Fair enough. Altho people have spoken of time travel via rotating black 
holes and such, but I suppose that's speculation until someone finds one 
for sure. :-)

>   I think you could clearly see the event horizon regardless of its size
> because of the way it bends light.

Yes, but all mass bends light. Even "dark matter". :-)  It's kind of the 
GR definition of "mass".

>   Once inside, you are doomed. There's no escaping the singularity.
> You'll go there no matter what you do.

Yep. Big Crunch. :-) I think the math for charged rotating black holes, 
or those taking into consideration quantum effects, are less obvious.

>>  > However, if GR is right, everything inside
>>> the event horizon inevitably goes to the singularity and there just isn't
>>> escaping it. You just can't keep away from it no matter what you try.
> 
>> Sure. Let me know when you figure out how to escape the universe. :-)
> 
>   Nothing is going towards a global singularity in the universe. On the
> contrary, everything is going away from everything else.

At the moment, yes.

>>>> Surely you're not asking seriously? A sphere is a 2D finite surface with 
>>>> no border.
>>>   The sphere is its own border.
> 
>> No, the sphere is a border for a ball, not a sphere.
> 
>   A ball is a sphere.

Mathematically speaking, when mathematicians distinguish "sphere" from 
"ball", the latter includes the points at distance < radius, while the 
former includes only points at distance = radius.

http://mathworld.wolfram.com/Ball.html

(Occasionally I surprise myself with the useless information that sticks 
in my head. Last week it was the reproductive cycle of jellyfish.)

The reason I made the distinction was to imply that the surface of a 
sphere would be unbounded (as in, without any boundaries) to an entity 
restricted to the surface. Sure, you couldn't change your radius, but 
that's by definition of it being restricted to a sphere. An entity in a 
ball, on the other hand, can move outwards from the center and hit a 
boundary at the radius.

I believe Aristotle had an interesting insight (right or wrong). If 
there is a boundary to the universe, and you throw a rock at the 
boundary, what stops the rock? There can't be anything outside the 
boundary to stop the rock.

>   Perhaps you are confusing it with a spherical surface?


-- 
   Darren New / San Diego, CA, USA (PST)
     It's not feature creep if you put it
     at the end and adjust the release date.

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