Warp wrote:
>   I think the time travel is related to wormholes. 

Some is, yes. Negative density mass can do that.

> Travelling inside a
> wormhole does not imply going inside the event horizon of a black hole.

http://science.howstuffworks.com/time-travel2.htm

Right, but a rotating black hole might not have a singularity, and you 
might be able to get out of the "event horizon" somewhere else.

>>>   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".
> 
>   I said "they way it bends light", not "because it bends light".

Ah, I misinterpreted.

>   No mass is dense enough to bend light like a black hole does because,
> obviously, if the mass was dense enough, it would collapse into a black
> hole...

Fair nuff.

>   The Big Crunch means that the universe, ie. space itself, contracts
> until everything collapses into a singularity. Contraction of space doesn't
> involve objects moving. 

I've never understood whether the expansion of space also implies the 
expansion of the particles in that space. Actually, come to think of it, 
that's a question relating GR to QM, so I'm not sure anyone knows. :-)

>   A black hole doesn't contract. Instead, objects physically move towards
> the singularity.

Hmmmm.

>   I can't say for sure, but I have the understanding that anything going
> away from the singularity inside the event horizon of a black hole would
> be against GR equations.

That certainly sounds intuitively correct, yes.  But again, where would 
the "singularity" of the universe be? How could you be "going away" from 
it? Especially if your "going away" was caused by the expansion of 
space, which as you say does not involve actual movement? :-)

>   Whatever floats your boat.  ;) 

It came up because I was here last week:
http://www.youtube.com/watch?v=AtRHzcwjc1k

Very cool trip.

-- 
   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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