On 19-1-2010 12:43, gregjohn wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> For example, almost
>> all of a neutron star is made of neutrons, so there is much
>> more non-empty matter out there than she thinks.
> 
> 
> Right, the neutron star is an obvious disproof of the bowling-ball-matter
> factoid. Perhaps I gave her too much benefit of the doubt on that. However, I
> remember my Lutheran catechismal materials in 8th grade making philosophical
> reflections about the fact that most ordinary matter around us is mostly open
> space.  I have a vague recollection of some reputed scientist-- Sagan??-- doing
> the same.
> 
That is correct. I was unable to watch the entire video. With respect to 
  putting all mass in one place. At a certain compression you get the 
famous black hole. The size of the Schwartzschild radius increases 
linearly with mass i.e. faster than the cubic root of the mass.
IIRC if you would put the enire mass of the universe into a blackhole it 
would have a radius of half the universe or so. Or at least something 
slightly bigger than a bowling ball.

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