A couple of black hole questions

[Royston]

I was having a look at NTSA website on black hole simulations and I noticed that the graphics are based on a 2 dimensional plane with the forming of the black hole represented in three dimensions. The (debatable) singularity therefore being represented as an everdecreasing cone.

 

I've always imagined blackholes as a star collapsing into a smaller and smaller sphere with space-time curving inwards as the star collapses. The event horizon being the curvature where the star once was, what happens past this point is a bit more tricky to wrap your head round...there are numerous theories.

 

It's quite hard to visualize this...if you imagine yourself on the sphere and everything curving in as it collapses (including yourself) thinking of this in three dimensional space then this seems more logical than the graphic interpretations I've looked at. Is my thought process correct ?

 

Also given that the force of gravity is equal on the surface area of a star (correct me if this is wrong) then the star should theoretically collapse evenly. This to my mind would create a static black hole...so my second question is, what constitutes a rotational black hole. Is it dependant on it's surroundings when it collapses ?

 

My third question is, is there a computer simulation that has managed to graphically represent the collapse of a star in four dimensions rather than on a two dimensional surface of a sphere ?

 

If I'm getting this completely wrong I'm open to criticism. Are static black holes created for hypothetical mathematical models rather than actually existing, considering that the universe is constantly rotating and expanding ?

 

More than a couple of questions I know, but I'd really like to try and visualize what's going on when a star collapses.

[[Tycho?]]

Visualizing a black hole using that two/three dimensional graph surface is done for convienience. Trying to imagine it in three dimensions, plus time, gives you 4 dimensions to visualize, which seems to be impossible for human brains.

 

About the star collapsing evenenly: I doubt any start would collapse in a perfectly even way, how could it? Density will vary slightly throughout the star, plus you would get a bulge around the equator due to rotation (although this is extremely small). I dont know how or why a rotating black hole (they're called Kerr black holes) would form instead of a static one. Check wikipedia.

 

These simulations do it in 4 dimensions. But how does one display on a screen something that is happening in 4 dimensions? Again, that grapic representation is just there so our puny little eyes and minds can get a grip on what is actually occuring.

 

http://www.wikipedia.com will help you out a lot.

[Royston]

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About the star collapsing evenenly: I doubt any start would collapse in a perfectly even way' date=' how could it?

http://www.wikipedia.com will help you out a lot.[/quote']

 

Gravity is even over the surface area whether there are mountains or other small blemishes...otherwise we would have different forces of gravity at certain altitudes. Small inflamations on a star are nothing to a force that collapses a mass that size.

[Xyph]

We do have "different forces of gravity at certain altitudes". The difference is completely negligible, but there, nonetheless. Although true, surface imperfections on the surface of a star wouldn't translate to something similar on the "surface" of the black hole.

[J.C.MacSwell]

Gravity is even over the surface area whether there are mountains or other small blemishes...otherwise we would have different forces of gravity at certain altitudes[/b']. Small inflamations on a star are nothing to a force that collapses a mass that size.

 

We do!

[Royston]

Oh...well I've embarassed myself yet again. The universe has no bounds, just like my stupidity. I'll be sure to research a topic thouroughly before I start a thread in future.