What happens when a neutron star collapses into a black hole?

[Drakkith]

Well, super collider experiments show a smashed nucleus breaks down to mostly radiation plus 3 quarks and a little bit of other small exotic particles.

Particles collide at enormous energies inside of colliders, and it is that extra energy that is converted to radiation and other particles. I'm not sure if you would say that a nucleus "breaks down" under enormous pressures or not. It seems to me that as the pressure increases the atom is converted into a higher energy state as the electrons and protons are transformed into neutrons. Beyond that, if the neutrons form quark matter, then wouldn't they be in an even higher energy state, and not release particles or radiation? Looks like the nucleons "merge" together in a quark soup or something.

 

[Bernie G]

"Beyond that, if the neutrons form quark matter, then wouldn't they be in an even higher energy state, and not release particles or radiation? Looks like the nucleons "merge" together in a quark soup or something."

I could go along with that. I want to calculate the radius of a star of relativistic material using the viral theorem. Do you have a suggested pressure formula as a function of density for this quark soup?

 

[Bernie G]

I think the pressure of this quark soup would also be (rho)(c^2)/3. See:
http://www.strw.leidenuniv.nl/~nefs/FermionGas.pdf

 

[Bernie G]

Pressure of (rho)(c^2)/3 is enormous and I think this would prevent collapse of the quark star, although the radius would be smaller than the Schwarzschild radius.

 

[Bernie G]

I think this star gravitationally is Newtonian, except for an atmosphere where effective gravity shifts to relativistic.

(rho)(c^2)/3 indicates a supporting energy of M(c^2)/3 , which indicates gravitational potential energy of 2M(c^2)/3 .

 

[Orion1]

Neutron stars if not anything else, are composed mostly of fundamental particles called quarks and gluons in the form of degenerate neutrons. And according to Loop Quantum Gravity (LQG), when a neutron star collapses, the matter inside a black hole becomes a relativistic quark-gluon plasma, which gravitationally collapses and rebounds in an oscillation on the order of a Planck singularity. In this sense, black hole cores are the ultimate atom smashers in the Universe.

The pressures and densities cited by this thread are used to describe the pressure and densities inside neutron stars, also known as a 'Fermion gas', which depending on the mathematical model of their Equation of State, can be relativistic or non-relativistic, and inside black holes, with the consideration of relativistic quark-gluon plasma pressures and densities, curve into relativistic Planck pressure and Planck density.

The pressures and densities inside the core of a black hole are on the order of Planck pressure and Planck density.
[/Color]
Reference:
Loop quantum gravity - Wikipedia

 

[Bernie G]

The Wiki article on Loop quantum gravity is vague. Can you give an equation for the Plank pressure or density in a black hole?

I think a gravitationally contained quark matter star would experience a pressure of about (rho)(c^2)/3 and have a radius between R = (1.2GM)/(c^2) and R = (1.5GM)/(c^2).

 

[Bernie G]

I did the calculation for gravitational potential energy using a density profile of
[1 - (r^2)/(R^2)] and came up with 1.1 G (M^2)/R. Not sure if this is correct. Does anybody have the equation for gravitational potential energy using a density profile of
[1 - (r^2)/(R^2)] ?

 

[Bernie G]

1.1 G (M^2)/R seems too high for the Newtonian gravitational energy based on [1 - (r^2)/(R^2)] ... I think at most it should be 1.0 G (M^2)/R ... I'll go over it again and will post it here, but won't get to it for several days.