Am 22.07.2010 22:17, schrieb Jim Henderson:
> On Thu, 22 Jul 2010 15:18:50 -0400, Warp wrote:
>
>>    Because you can't have a huge bunch of particles in a space of zero
>> volume.
>
> I'm not a physicist (though I know a few people who are), but ISTR
> reading/hearing that a 'singularity' isn't defined as a space with zero
> volume.  It's a very densely packed collection of matter, but not with
> zero volume.

Actually, AFAIK a "singularity" is defined as any condition in which the 
formulae of a theory don't give any meaningful answer.

In GR, you can pack matter arbitrarily dense in any non-zero volume 
without the formulae breaking down, so no - I guess you're wrong.

However, you may be not so far off the mark regarding black holes: 
AFAIK, those indeed typically have a non-zero (though ever shrinking) 
volume, as in order to form a true singularity you'd need a neatly 
symmetric collapse.

Thus, the problem with black holes is probably not the singularity /per 
se/: To me it looks like that's a purely academic issue because there 
bloody likely aren't any such beasts out there in reality. Instead, the 
problem with black holes is that ever-shrinking thing, which doesn't go 
along well with QED's prediction of a lower bound on distances.

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