
#415
Dec2312, 09:24 AM

P: 1,657





#416
Dec2312, 09:53 AM

Sci Advisor
PF Gold
P: 4,862





#417
Dec2312, 12:28 PM

Physics
Sci Advisor
PF Gold
P: 5,508

Actually, even that is not really the right way to say it. The Pauli exclusion principle as we have stated it is not a fundamental law; the fundamental law is that fermion wave functions are antisymmetric under particle exchange, whereas boson wave functions are symmetric. If I have a boson, say a spin0 particle, at spacetime position x, and another spin0 particle of the same particle type at spacetime position y, the wave function is symmetric under exchange of those two particles. But if I have a fermion in a definite spin state, say a spinup electron, at spacetime position x, and another spinup electron at spacetime position y, the wave function is antisymmetric (i.e., it changes sign) under exchange of those two particles. The Pauli exclusion principle, which says that the wave function is identically zero if x = y, is an obvious consequence of the antisymmetry. However, it's not the only consequence; another consequence is that as x and y get closer together, the amplitude of the wave function decreases. That's what causes degeneracy pressure. But all of that is below the level that GR models anyway. GR doesn't care about the microscopic details of matter; all it cares about is the stressenergy tensor. Degeneracy pressure, from the standpoint of the stressenergy tensor, works just like any other kind of pressure. The only real difference is the equation of state, i.e., the relationship between pressure and energy density. 



#418
Dec2412, 01:55 AM

PF Gold
P: 1,376

Your assumptions seems to be that particles affect occupancy of quantum levels only over short distance. I assume that occupancy of quantum level drops as inverse square law as we go further from the particle. 



#419
Dec2412, 05:14 AM

PF Gold
P: 1,376





#420
Dec2412, 07:33 AM

Mentor
P: 16,477

I.e. your assumption "Formation of EH relies on idea that gravitating object can get more compact" is not correct. The formation of the singularity relies on that, but not the EH. The EH can form with simply a very large amount of noncompact material and you do not need a singularity in order to obtain an EH. So again, what would prevent the formation of the EH? Degeneracy won't do it, that would only prevent the formation of the singularity. 



#421
Dec2412, 10:51 AM

Sci Advisor
PF Gold
P: 4,862





#422
Dec2412, 11:27 AM

Physics
Sci Advisor
PF Gold
P: 5,508





#423
Dec2512, 01:42 AM

PF Gold
P: 1,376

First, we can add more matter to given gravitating object while it's radius is not increased too much by this addition. Second, we can make given gravitating object more compact while it's mass is not reduced too much by this compactification. I guessed that you was talking about the second scenario. If you are considering first scenario and want arguments concerning this scenario in particular please say it so that I don't have to guess. 



#424
Dec2512, 01:44 AM

PF Gold
P: 1,376





#425
Dec2512, 02:02 AM

PF Gold
P: 1,376

So what I say is that if we have two fairly degenerate stars approaching each other then whey would melt first and after that will start to evaporate. Or alternatively will fall into pieces depending on homogeneity of star. If particles can't remain in their quantum states they can't maintain their collective structure. Kind of obvious IMO. 



#426
Dec2512, 06:42 AM

Mentor
P: 16,477

In general an EH forms whenever there is enough mass inside the Schwarzschild radius. That can happen at any density, so a mechanism which prevents high densities, like degeneracy, simply cannot prevent EH formation in general. 



#427
Dec2512, 11:00 AM

P: 1,657





#428
Dec2512, 11:07 AM

P: 1,657





#429
Dec2512, 12:21 PM

Physics
Sci Advisor
PF Gold
P: 5,508

http://en.wikipedia.org/wiki/Tolman%...3Volkoff_limit Conceptually, both limits work the same, but the details are different because of the different types of fermions involved (neutrons vs. electrons). 



#430
Dec2512, 12:24 PM

Physics
Sci Advisor
PF Gold
P: 5,508





#431
Dec2512, 12:26 PM

Physics
Sci Advisor
PF Gold
P: 5,508





#432
Dec2512, 12:28 PM

Physics
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PF Gold
P: 5,508




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