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Quark stars might even be a stage on the way to collapse from neutron star to black hole. The collapse is fast, but not instantaneous, so what would those neut

Quark stars might even be a stage on the way to collapse from neutron star to black hole. The collapse is fast, but not instantaneous, so what would those neutrons become once their degeneracy pressure is exceeded?

sigmoid10 2y ago
>what would those neutrons become once their degeneracy pressure is exceeded That kind of depends on what the equation of state looks like for quark matter. If you look at black hole formation from a theoretical perspective (e.g. as a collapsing shell of matter), it is very much possible that neutrons transition directly into a black hole before entering a new state. Unfortunately, we have no idea about the equation of state and this stuff is very far beyond anything that could be studied experimentally in a collider. It's admittedly a fascinating topic, but there is very little rigorous science surrounding it.
- cryptonector 2y ago
  > it is very much possible that neutrons transition directly into a black hole before entering a new state At least the neutrons that start out being outside the Schwarzschild radius of the black-hole-to-be cannot transition directly into being in a black hole state because they have to first move from where they are to the event horizon, and that has to take some non-zero amount of time since they can't exceed the speed of light on the way to the event horizon. It's possible that with the degeneracy pressure exceeded they just don't become something else, but instead simply move... through each other? That makes little sense. Since they are made up of quarks what makes sense instead is that they become quark soup on the way to the event horizon. Though there are other possibilities too. Maybe all the neutrons turn to photons going towards the incipient black hole and without becoming quark soup first, they they can travel through each other. > Unfortunately, we have no idea about the equation of state and this stuff is very far beyond anything that could be studied experimentally in a collider. It's admittedly a fascinating topic, but there is very little rigorous science surrounding it. The best we could do is check different theories for consistency, but we can't test them unless those theories make predictions about electromagnetic emissions or gravity wave emissions from a neutron star collapse that we might be able to observe and which could be used to test those predictions.
  - sigmoid10 2y ago
    >they have to first move from where they are to the event horizon No. I mean, from their point of view it would seem they kind of have to do, but there are some serious open questions about what happens here exactly. Regardless, as an outside observer, you would never see them actually move behind the horizon, you would only see the black hole grow beyond the point where they used to be. For a detailed description of all this you can check out chapter 32 of MTW's Gravitation. >Since they are made up of quarks what makes sense instead is that they become quark soup on the way to the event horizon Again, this depends on the equation of state and the existance and location of transition points. We don't know any of those things - but we do know that any realistic model must include general relativity, because quantum effects alone are no longer sufficient to describe what happens here. At that level all bets are off. >The best we could do is check different theories for consistency That is one thing. But it is also kind of moot since this is where string theory has been stuck for half a century now.

sigmoid10 2y ago

>what would those neutrons become once their degeneracy pressure is exceeded That kind of depends on what the equation of state looks like for quark matter. If you look at black hole formation from a theoretical perspective (e.g. as a collapsing shell of matter), it is very much possible that neutrons transition directly into a black hole before entering a new state. Unfortunately, we have no idea about the equation of state and this stuff is very far beyond anything that could be studied experimentally in a collider. It's admittedly a fascinating topic, but there is very little rigorous science surrounding it.

cryptonector 2y ago
> it is very much possible that neutrons transition directly into a black hole before entering a new state At least the neutrons that start out being outside the Schwarzschild radius of the black-hole-to-be cannot transition directly into being in a black hole state because they have to first move from where they are to the event horizon, and that has to take some non-zero amount of time since they can't exceed the speed of light on the way to the event horizon. It's possible that with the degeneracy pressure exceeded they just don't become something else, but instead simply move... through each other? That makes little sense. Since they are made up of quarks what makes sense instead is that they become quark soup on the way to the event horizon. Though there are other possibilities too. Maybe all the neutrons turn to photons going towards the incipient black hole and without becoming quark soup first, they they can travel through each other. > Unfortunately, we have no idea about the equation of state and this stuff is very far beyond anything that could be studied experimentally in a collider. It's admittedly a fascinating topic, but there is very little rigorous science surrounding it. The best we could do is check different theories for consistency, but we can't test them unless those theories make predictions about electromagnetic emissions or gravity wave emissions from a neutron star collapse that we might be able to observe and which could be used to test those predictions.
- sigmoid10 2y ago
  >they have to first move from where they are to the event horizon No. I mean, from their point of view it would seem they kind of have to do, but there are some serious open questions about what happens here exactly. Regardless, as an outside observer, you would never see them actually move behind the horizon, you would only see the black hole grow beyond the point where they used to be. For a detailed description of all this you can check out chapter 32 of MTW's Gravitation. >Since they are made up of quarks what makes sense instead is that they become quark soup on the way to the event horizon Again, this depends on the equation of state and the existance and location of transition points. We don't know any of those things - but we do know that any realistic model must include general relativity, because quantum effects alone are no longer sufficient to describe what happens here. At that level all bets are off. >The best we could do is check different theories for consistency That is one thing. But it is also kind of moot since this is where string theory has been stuck for half a century now.