Compressing matter to < 1 hodon and black holes

[K.I.L.E.R]

A black hole is formed when you compress existing matter into some horribly small space.
My question is, if you compress a quantity of matter into a space of 1 hodon or less, is that a requirement in order to form a black hole?

 

[Bobbler]

No idea what a Hodon is, but iirc it's just a ratio of matter per area (density) that needs to be met (dense enough that light can't escape) and you essentially have yourself a blackhole in the making. Compressing it to a certain physical size shouldn't matter so much, just a certain density and the rest should take care of itself.

I'm no physics professor, but that seems to be how it would work logically.

 

[3dilettante]

Compressing mass to the point that the local gravity is strong enough to capture light is all that is needed.

There are some theoretical limits, I think.
The lesser the starting mass, the more compressed it must be. I don't have much knowledge of the ratios, but if a mass is so small that it needs to be compressed to below a planck unit of space, then a black hole should not form.

It is also believed that black holes do emit radiation, thanks to quantum behavior of virtual particles straddling the event horizon.
Smaller black holes are believed to radiate more, past some threshold, they start radiating energy like crazy.
As a result, the black hole's event horizon shrinks as the equivalent mass is lost. No one is sure what happens exactly when the mass drops to very low levels, but it's postulated the singularity ceases to exist in one form or another.

If the sample of mass is too small, it is possible that the black hole would evaporate very quickly.

 

[Frank]

Alternatively, I think that it might be very well possible that to gravity the matter density is uniform throughout the universe. So, to a graviton, black holes might not exist at all. Black holes and other massive objects are only a matter of entropy: the quantum shells of matter tend to seek equivalent surfaces to all neighbors, and try to limit the "surface", like soap bubbles. The bubbles just get very small when there is a lot of matter together. It just looks like a black hole outside the sphere where graviton communications exceed the speed of light, so to say.

That would get rid of gravity waves very neatly as well.

 

[Bigus Dickus]

If our universe were closed, which it looks as if it isn't, you could argue that we live inside a black hole.

 

[K.I.L.E.R]

I thought black holes would crush a person or entity?
The only black hole which I've read that a human can stand close to without issue is a solar massive one, apparently the smaller black holes are the dangerous ones.

If our universe were closed, which it looks as if it isn't, you could argue that we live inside a black hole.

 

[Ateo]

Alternatively, I think that it might be very well possible that to gravity the matter density is uniform throughout the universe. So, to a graviton, black holes might not exist at all. Black holes and other massive objects are only a matter of entropy: the quantum shells of matter tend to seek equivalent surfaces to all neighbors, and try to limit the "surface", like soap bubbles. The bubbles just get very small when there is a lot of matter together. It just looks like a black hole outside the sphere where graviton communications exceed the speed of light, so to say.

That would get rid of gravity waves very neatly as well.

Gravity exceeding the speed of light?
Did you just toss out Einsteins physics?

EM(electromagnetism), W(weak nuclear force), S(strong nuclear force) works well on the quantum level.
G(gravity) works fine on the large scale.

You bet there is gravity in a black holes, that is what forms/maintains the singularity to start with
The string theroy might unity all the 4 forces, hopefully the comming new BIGGER particle acceleration at CERN will show us if we ar moving hte right way

Video for the interested:
http://video.google.com/videoplay?docid=4258041398583592305&q=elegant+universe
http://video.google.com/googleplayer.swf?docId=4946534495911911377&hl=en
http://video.google.com/googleplayer.swf?docId=5253371475737693133&hl=en

I like the string theroy, is just as pretty as E=mc^2

 

[Fred]

The amount of misconceptions in this thread exceeds my sanity threshold!

I suggest the black hole faq at John Baez's homepage
http://math.ucr.edu/home/baez/physics/