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Question about Black Holes



 
 
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  #1  
Old July 21st 06 posted to sci.physics.relativity,sci.physics
cafeinst@msn.com
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Posts: 130
Default Question about Black Holes

Is a black hole a singularity in the space-time continuum, meaning it
is just a point in space-time? Or does it have "volume"?

If it is just a point, then does it have any mass? (I remember learning
that a black hole is caused by a collapsed star.)

This all seems to me to be a little crazy, like the question, "how many
angels can fit on the head of a pin?" How can you study something that
you don't have any experience with?

Craig

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  #3  
Old July 21st 06 posted to sci.physics.relativity,sci.physics
uri
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Posts: 546
Default Question about Black Holes

This universe is mostly black: 95% is black.

  #4  
Old July 21st 06 posted to sci.physics.relativity,sci.physics
Igor
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Default Question about Black Holes


uri wrote:
This universe is mostly black: 95% is black.


Actually, it's beige.

  #5  
Old July 21st 06 posted to sci.physics.relativity,sci.physics
T Wake
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Default Question about Black Holes


"uri" wrote in message
ups.com...
This universe is mostly black: 95% is black.


Is black a colour?


  #6  
Old July 21st 06 posted to sci.physics.relativity,sci.physics
Phineas T Puddleduck
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Default Question about Black Holes

In article , T Wake
wrote:

"uri" wrote in message
ups.com...
This universe is mostly black: 95% is black.


Is black a colour?


None more black. The universe goes up to 11, you know.... '-)

--
Relf's Law? -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"Bull**** repeated to the limit of infinity asymptotically approaches
the odour of roses."
Corollary -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
³It approaches the asymptote faster, the more Œpseduos¹ you throw in
your formulas.²
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
³Gravity is one of the four fundamental interactions. The classical
theory of gravity - Einstein's general relativity - is the subject
of this book.² : Hartle/ Gravity pg 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jaffa cakes. Sweet delicious orange jaffa goodness, and an abject lesson
why parroting information from the web will not teach you cosmology.
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

--
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  #7  
Old July 22nd 06 posted to sci.physics.relativity
G=EMC^2 Glazier
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Posts: 5,002
Default Question about Black Holes

Sam The star that collapses to create a black hole has to have three
times more mass density than the star that creates a neutron star. To me
a singularity at the center of all black holes has no physical shape.
Sam if I'm wrong jump in an tell us its shape and structure. How about
just a round dot. Naturally I have a "critical mass density of a black
hole.theory" You must have read it in my other news groups
Bert

  #8  
Old July 22nd 06 posted to sci.physics.relativity
Phineas T Puddleduck
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Posts: 2,627
Default Question about Black Holes

In article , G=EMC^2
Glazier wrote:

Sam The star that collapses to create a black hole has to have three
times more mass density than the star that creates a neutron star. To me
a singularity at the center of all black holes has no physical shape.
Sam if I'm wrong jump in an tell us its shape and structure. How about
just a round dot. Naturally I have a "critical mass density of a black
hole.theory" You must have read it in my other news groups
Bert



Nope

the critical mass that dictates whether neutron star or black hole is
around 3 solar masses. Try again saucerhead.

--
Relf's Law? -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"Bull**** repeated to the limit of infinity asymptotically approaches
the odour of roses."
Corollary -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
³It approaches the asymptote faster, the more Œpseduos¹ you throw in
your formulas.²
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
³Gravity is one of the four fundamental interactions. The classical
theory of gravity - Einstein's general relativity - is the subject
of this book.² : Hartle/ Gravity pg 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jaffa cakes. Sweet delicious orange jaffa goodness, and an abject lesson
why parroting information from the web will not teach you cosmology.
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

--
Posted via a free Usenet account from http://www.teranews.com

  #9  
Old July 22nd 06 posted to sci.physics.relativity,sci.physics
N:dlzc D:aol T:com \(dlzc\)
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Posts: 6,805
Default Question about Black Holes

Dear cafeinst:

wrote in message
oups.com...
Is a black hole a singularity in the space-time
continuum, meaning it is just a point in
space-time? Or does it have "volume"?


A black hole is bounded in our Universe by an event horizon. We
can assign a volume to the event horizon, but it is not something
physical. What we can measure about a BH are things like
Einstein rings, and gravitational time dilation of closer orbits.
We can measure its mass, and observe that it has no visible
surface.

If it is just a point, then does it have any mass?
(I remember learning that a black hole is caused
by a collapsed star.)


Some of them may have been primordial, meaning they were never
stars. Yes, its mass is what makes it remain a BH.

This all seems to me to be a little crazy, like the
question, "how many angels can fit on the head
of a pin?"


That particular question was intended to "sort out" your
religious denomination. The "chicken and egg" question was
intended to reveal whether you were a creationist or an
evolutionist.

How can you study something that
you don't have any experience with?


We have observed objects that are as massive or more massive than
identified neutron stars, but have no surface interactions.
Things smash together outside it, and tehn disappear entirely
from view. Neutron stars have very energetic surface
interactions that we can observe.

David A. Smith


  #10  
Old July 22nd 06 posted to sci.physics.relativity,sci.physics
tadchem
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Posts: 2,203
Default Question about Black Holes


wrote:
Is a black hole a singularity in the space-time continuum, meaning it
is just a point in space-time? Or does it have "volume"?


"Singularity" does not necessarily imply a single point.
http://mathworld.wolfram.com/Singularity.html
The function

F(x,y,z,t) = 1/(x^2 + y^2 + z^2 -c^2*t^2)

has as a 'singularity' a sphere of radius c*t.

snip

This all seems to me to be a little crazy, like the question, "how many
angels can fit on the head of a pin?" How can you study something that
you don't have any experience with?


Mathematically.

BTW, the best answer I have seen to the dancing angels question is "All
of them."

Tom Davidson
Richmond, VA

 




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