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thr33pwood t1_ivjpu39 wrote

Reply to comment by Ixneigh in Bizarre star may have a solid surface, according to X-ray observations. Astronomers have now spotted a super strange one that seems to have a solid surface. Its intense magnetic field is strong enough to overcome its blistering temperatures and “freeze” its outer layers into a solid crust. by MistWeaver80

No. That would be White Dwarfs.

A magnetar is a type of neutron star. It is made up of densely packed neutrons. It is a form of matter that is unlike anything we know here on earth. All the matter we know, all elements are made up of Atoms. An atom is neutrons and protons(+) surrounded by electrons(-). Atoms attract and repell each other.

Even in the most dense material known on earth there is 99.99999% empty space between any of the actual particles.

In a neutron star, the gravitational force has become so strong that these repelling forces of the atoms are overcome and the cores of the atoms got crushed together.

This is exotic matter unlike anything we have experience with.

Neutron stars are incredibly compact. They are around 10 kilometers across in size while having around 1.4 times the mass of our sun - which is more mass than our whole solar system has.

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Ixneigh t1_ivjtw3e wrote

Ok, what would happen you some how got a small sample? Would it “unspring” into lighter elements?

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thr33pwood t1_ivjvxuw wrote

I am not an astrophysicist, but I believe nobody knows.

This is an interesting question that basically boils down to "is this form of matter stable?".

But if it is not stable in the presence of continued gravitational force, I believe "unspring" would not describe very well what would "or could" happen then. Because hypothetically the amount of potential energy stored in this is magnitudes higher than nuclear fission or nuclear fusion would provide.

If I had to guess a sample of this kind of matter would be either stable (if there is an interaction holding these neutrons together) or it would make all nukes on earth look like a firecracker.

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Sad-Platypus t1_ivng5n9 wrote

I too am not an astrophysicist so we are two both talking out of our depths. But, some other things to think about.

Would it have a lot of potential energy? Maybe in the sense of a phase change (water - steam 100X volume increase) so 1 ml might expand to 1GL in that sense of explosion.

It is my understanding that while the gravity is keeping it all together, most of the "energy" is consumed in the crush when electrons and protons are merged from all the atoms to form the neutron soup. So once that has happened would they spontaneously go back to being atoms if the gravity was removed?

Neutrons are neutral charge, so no electromagnetic forces would try to push the particles apart. Instead, strong nuclear force might keep it all together even without all the gravity.

Free Neutrons are unstable and decay to hydrogen with a half life of 10 min

If I were a betting man, I would think it would be "stable" in the sense that it wouldn't explode itself, but would be highly radioactive in weird radioactive ways we've never seen.

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