I was curious if it would be possible for blackholes to actually just be neutron starts that are so large that they trap light and gain mass from nearby objects. If this were true that would mean that blackholes that we have observed to get larger were just neutron stars adding onto their mass and enlarging their gravity well.

I fully agree with things associated with black holes such as spaghettifacation and the event horizon. Im not exactly a professional on these things but I just want to know your opinion on if you think it may be a neutron star/wormhole/singularity because it would be interesting if black holes had a surface of some sort.


closed as primarily opinion-based by David Z May 3 '16 at 17:02

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ This question shows a lack of research effort. The difference between a neutron star and a black hole can easily be found from an internet search. $\endgroup$ – sammy gerbil May 3 '16 at 17:09
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    $\begingroup$ This question is a possible duplication of physics.stackexchange.com/q/113892. There are several other closely-related questions indicated in the right-hand panel. $\endgroup$ – sammy gerbil May 3 '16 at 17:14

There is a very general theorem that there is no stable configuration of matter that can exist above a threshhold that fundamentally just depends on the mass of the constituent particles that make up the matter (and the interatomic forces in the matter).

There is some debate about the exact limit for neutron stars, but it is something like 2.5 - 3 solar masses. If a neutron star obtains more mass than this, it will be inherently unstable, and will either eventaully collapse to a black hole, or it will have to expel matter.

Incidentially, the fact that this instability always happens at the same mass means that the explosion/collapse event that follows is remarkably similar from neutron star to neutron star, and this means that these become sources of known brightness, which can then be used as a means to determine cosmic distances:


  • $\begingroup$ I think you are mistaking type Ia supernovae for the collapse of neutron stars? $\endgroup$ – Rob Jeffries May 3 '16 at 21:21
  • $\begingroup$ @RobJeffries No, he is suggesting another type of stellar collapse. The question is whether there is a mechanism that allows a neutron star to slowly accrete mass. $\endgroup$ – Lewis Miller May 4 '16 at 3:02
  • $\begingroup$ @LewisMiller So which astronomical sources/explosions have been identified as collapsing neutron stars? And why would there be an explosion? The collapse results in the neutron star vanishing inside its Schwarzschild radius. $\endgroup$ – Rob Jeffries May 4 '16 at 6:07
  • $\begingroup$ @RobJefferies None that I know of and there won't be any unless some accretion mechanism similar to type 1a exists. It would not be an explosion, but perhaps a lot of gamma rays and cosmic rays would result. There is, nevertheless, a maximum size for a neutron star and my comment was really a question of what signature would result should one cross the threshold and collapse into a BH. $\endgroup$ – Lewis Miller May 6 '16 at 20:06

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