Mojo says hi

Mojo says hi

Post by Dan Bloomfie » Mon, 11 Sep 1995 04:00:00




DA>:    r = 2MG / c^2,

DA>: where

DA>:    M is the stellar mass,
DA>:    G = 6.6720 * 10^-11 m^3 / s^2 kg is the gravitational constant, and
DA>:    c = 2.997 * 10^8 m/s is the speed of light.

A much easier way to figure the size of a black hole is that the radius of a
hole of 1 stellar mass is approximately three miles. For larger masses just
scale that up.

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Mojo says hi

Post by davewar.. » Tue, 12 Sep 1995 04:00:00


: A much easier way to figure the size of a black hole is that the radius of a
: hole of 1 stellar mass is approximately three miles. For larger masses just
: scale that up.

Well, we've had less relevant threads on this list, so I guess we may as
well keep it going....

What do you mean by this "three miles" statement?  I was under the
impression that the size of black holes would change as they absorbed more
and more matter, starting off VERY small with miniscule Event Horizons
(cheap plug) and then growing to gargantuan proportions...the latest news
is that the black hole at the center of our galaxy is a big sucker, but
compared to black holes in other galaxies that we MAY have found evidence
of, it's small.  

I'll have to dig out my copy of "Brief History of Time" and see what our
buddy Stephen has to say about this....is Hawking on the net?

--
                                     -David Warner

 
 
 

Mojo says hi

Post by Ernie Wrigh » Wed, 13 Sep 1995 04:00:00



> I was under the impression that the size of black holes would change as
> they absorbed more and more matter, starting off VERY small with miniscule
> Event Horizons (cheap plug) and then growing to gargantuan proportions...

The less controversial idea about black holes is that they form when a
star of at least 3 solar masses collapses.  They're small on astronomical
scales, but they're at least 11 miles wide.  The radius increases linearly
with mass, so 3 more suns, 22 miles wide.  They start out kinda small and
mostly stay that way--they don't travel the galaxies sucking up stars.

Hawking proposed a quantum mechanical theory of black holes that allows
them to *emit* radiation.  The smaller they are, the faster they emit.
The theory can't be tested on regular-size black holes because they emit
too weakly.  We need atomic scale black holes, and nobody's seen one yet.

- Ernie

 
 
 

Mojo says hi

Post by Ernie Wrigh » Wed, 13 Sep 1995 04:00:00



> A much easier way to figure the size of a black hole is that the radius
> of a hole of 1 stellar mass is approximately three miles. For larger
> masses just scale that up.

That's 1 *solar* mass and 3 *kilometers*.  One of the advantages of
knowing the equation...

- Ernie

 
 
 

Mojo says hi

Post by Kevin Hans » Fri, 15 Sep 1995 04:00:00





>> I was under the impression that the size of black holes would change as
>> they absorbed more and more matter, starting off VERY small with miniscule
>> Event Horizons (cheap plug) and then growing to gargantuan proportions...

>The less controversial idea about black holes is that they form when a
>star of at least 3 solar masses collapses.  They're small on astronomical
>scales, but they're at least 11 miles wide.  The radius increases linearly
>with mass, so 3 more suns, 22 miles wide.  They start out kinda small and
>mostly stay that way--they don't travel the galaxies sucking up stars.

>Hawking proposed a quantum mechanical theory of black holes that allows
>them to *emit* radiation.  The smaller they are, the faster they emit.
>The theory can't be tested on regular-size black holes because they emit
>too weakly.  We need atomic scale black holes, and nobody's seen one yet.

>- Ernie

I believe the Chandrasakar (sp?) limit is 1.4 solar masses.  Any object of
1.4 solar masses that can't counteract the crush of gravity (with, say, a
new round of fusion) will form a black hole.

Kevin

 
 
 

Mojo says hi

Post by Ernie Wrigh » Fri, 15 Sep 1995 04:00:00



> I believe the Chandrasakar (sp?) limit is 1.4 solar masses.  Any object
> of 1.4 solar masses that can't counteract the crush of gravity (with,
> say, a new round of fusion) will form a black hole.

Make that a neutron star.

The Chandresekhar limit is an upper limit on the mass of a stable white
dwarf.  Above this limit, an *infinite* central pressure is required to
prevent further collapse--no "new round of fusion" is sufficient.  Next
stop, neutron star, with stable configurations up to about 3 M sol, and
beyond that, nobody can think of a way to stop the collapse.

- Ernie

 
 
 

Mojo says hi

Post by kane » Fri, 15 Sep 1995 04:00:00


Quote:>Make that a neutron star.
>The Chandresekhar limit is an upper limit on the mass of a stable white
>dwarf.  Above this limit, an *infinite* central pressure is required to
>prevent further collapse--no "new round of fusion" is sufficient.  Next
>stop, neutron star, with stable configurations up to about 3 M sol, and
>beyond that, nobody can think of a way to stop the collapse.

Sure there is, you have to make a tachyon envelope inside the collapsing
structure.  Then flood the envelope with single sided polygons and then the
collapse will stop.  It is not unlike blowing air into a balloon, you just
need to know when to stop, or you could boolean subtract a hole of
infinite points into the space/time continuum.

Sorry, I couldn't resist. :)

Quote:>- Ernie

        Kane            --------------------------------------------
        Peterson       -- "Kane's World" World Wide Web Home Page: --
                       --      http://www.mcs.net/~kanep/www/      --

 
 
 

1. Mojo says hi.

  Mr. Mojo.  Brief comment on the Star Wars stuff.  To some degree I wholeheartedly
agree about inserting new effects or major alterations to Star Wars or other classic films,
at least not without allowing the original version to be seen.  Lucas is taking SW classic
away FOREVER now, and that irks me a lot.

  Although I don't like adding new effects, I wouldn't mind if the original SW footage
was fixed and cleaned up a bit.  Minor alterations could hide bad optical mistakes in the
movie.  An example is Obi-Wan's lightsaber.  Lit by front projection, it had a bad habbit
of dropping off to darkness when waved at certain angles.  Digital aniamtion could be used
to restore the glow in the dark frames.  Or when stormtroopers fire their guns, since they are
actual guns firing blanks, you can see the shells dropping to the floor in some shots.  Digital erasure
of the bullet shells and muzzle flash would give the guns their true laser look.

  I always thought that Lucas should have instead of updating the effects, used his
digital image manipulation tools like he used in Gump, to make a total digital restoration
of the negative to pristine color corrected grain minimized glory.

  One more thing.  You always professed to be a big Star Wars fan, and I always thought
you were doing Babylon 5 just as a means to eventualy join Lucas Digital when SW IV goes into
production.  I hope your negative comments in VTU didn't hurt future ILM prospects.  I think
future star wars films could use great space battle animaters like the ones who do B5.

2. Maxx support for AVI file format?

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