Chandrasekhar limit & Tolman–Oppenheimer–Volkoff limitby Astro.padma Tags: blackholes, chandrasekhar limit 

#1
Sep1711, 10:37 AM

P: 80

A nonrotating body of electrondegenerate matter above a certain limiting mass must have an infinite density. Now my question is : Why is it resulted as 1.4 times the solar mass in Chandrasekhar limit whereas things finally settled at 3 times the solar mass owing to the Tolman–Oppenheimer–Volkoff limit?? Could anyone please tell me what had brought the change in result of the later one??
and one more thing ... Which is considered as the correct one?? Thank you :) 



#2
Sep1711, 05:43 PM

Sci Advisor
P: 5,942





#3
Sep1711, 08:25 PM

PF Gold
P: 3,075

The lower limit is for degenerate electrons, the latter is for degenerate neutrons. Your question is actually a good one, because both electrons and neutrons need to go relativistic before these limits are reached, and at first glance you might think that electrons and neutrons would behave more or less the same once they are relativistic. But neutrons have access to other types of physics than electrons do, so that's one reason their "equation of state" is different from electrons, even when both are relativistic (in fact, the neutron equation of state is not well known).




#4
Sep1811, 08:34 AM

P: 80

Chandrasekhar limit & Tolman–Oppenheimer–Volkoff limit 



#5
Sep1811, 08:36 AM

P: 80





#6
Sep1811, 03:30 PM

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P: 5,942





#7
Sep1911, 09:28 AM

P: 80

Heard that there is a chance of micro black holes forming in the LHC working @ CERN but got to know that they don't usually and even if they form, they get evaporated within nano seconds. But I have no idea why there is a chance of micro black holes forming in the LHC. Could anyone please tell me why.




#8
Sep2011, 01:50 AM

Sci Advisor
PF Gold
P: 9,183

Mini black holes will not be produced by the LHC. The energy level is far too low. Were this untrue, we would be bombarded by mini black holes created by high energy cosmic ray collisions with the upper atmosphere.




#9
Sep2011, 08:29 AM

P: 80





#10
Sep2011, 05:43 PM

Sci Advisor
PF Gold
P: 9,183

In three dimensional space, the minimum energy necessary to form a microscopic black hole is about 10e+19 GeV. This would require a modern circular accelerator about 1000 light years in diameter. The low energy limit estimates [~ 1 TEV] for forming mini black holes assume higher dimensional space where gravity in the 'extra' dimensions can be much stronger. The LHC has found no evidence to date suggesting the existence of 'extra' dimensions.




#11
Sep2211, 09:25 AM

P: 80





#12
Sep2611, 01:18 AM

P: 6,863

Also the Chandrasekar calculations doesn't use general relativity. Special relativity is enough. 


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