Neutron Stars: Strong Force, Density & Black Holes

[Jonny_trigonometry]

Is a neutron star held together mainly by the strong force? Are they dense enough so that this is the case, or is gravity the only thing to consider? What about black holes?

 

[Chronos]

No, it's held together by gravity. The nuclear strong force is pretty much what prevents it from collapsing into a black hole.

 

[Jonny_trigonometry]

huh, now that doesn't make much sense to me. Doesn't the strong force act on any mass, and not care about charge? Therefore, it acts the same way as gravity (bosonic, is that the right word?), but just in a shorter range (10^-15 meters I think). So to me, if the neutron star becomes dense enough so that the strong force would take effect, then the core would pull together and the outside would come crashing into it to make a super dense conglomeration maybe even turning into a black hole...? This way of looking at it simply makes more sense to me.

I just don't see why it would prevent gravity from pulling everything together too much. If it acted in a way as to repel each neutron from the others, then it would prevent gravity from pulling them closer than 10^-15 meters apart, so that if matter was constantly being put into the system, the whole star would have a maximum density for a while until the strong force couldn't repel things enough to overcome gravity and the core would collapse. But this is not how it works as far as i understand.

 

[Labguy]

I just don't see why it would prevent gravity from pulling everything together too much. If it acted in a way as to repel each neutron from the others, then it would prevent gravity from pulling them closer than 10^-15 meters apart, so that if matter was constantly being put into the system, the whole star would have a maximum density for a while until the strong force couldn't repel things enough to overcome gravity and the core would collapse. But this is not how it works as far as i understand.

It is called degeneracy pressure. Electron degeneracy pressure keeps a White Dwarf from collapsing further. Add more mass, and this pressure is "overwhelmed" by gravity and it could collapse to a Neutron star. Then, we have neutron degeneracy pressure. Add more mass and we can collapse to a black hole.
The "Bosonic" fources you refer to are not attractive to where particles can occupy states as described (or excluded) by the Pauli exclusion principle; certain quantum states.
http://en.wikipedia.org/wiki/White_dwarf
http://en.wikipedia.org/wiki/Neutron_degeneracy_pressure