[lightarrow]

That may or may not be. In an atomic nucleus there is not 3×10¹² times Earth's gravity pressing them together. And that's just the surface gravity. I don't know what it is near the centre of a neutron star. That's what my question is about - what is the effect on the neutrons of that amount of gravity. Does it squeeze them together in such a way that their position & momentum could be known simultaneously? I don't see that talking about hydrogen atoms or neutrons in an atom addresses that question.

I don't know if it's possible to treat a singol neutron in a neutron star as individually distinct from all the others and so if it's correct to say that its wavefunction there is as more spatially localized as the pressure increases. It could even result that its wavefunction becomes less spatially localized (and so its position indeterminacy increases instead of decrease), going to take all the star's volume. For example, if you compress hydrogen atoms very very much (don't remember, maybe millions of atmospheres) it becomes a metal, because the atom's electrons becomes delocalized over all the bulk of material.

[DoctorBeaver (OP)]

It could even result that its wavefunction becomes less spatially localized (and so its position indeterminacy increases instead of decrease), going to take all the star's volume.

My poor little brain is having trouble with that.

[LeeE]

Is my information out of date?

Heh - I think that unless you're actively working in a field, the answer is usually yes  []

[DoctorBeaver (OP)]

Is my information out of date?

Heh - I think that unless you're actively working in a field, the answer is usually yes  []

I can't recall the last time I worked in a field apart from clearing up horse poo.

[lightarrow]

It could even result that its wavefunction becomes less spatially localized (and so its position indeterminacy increases instead of decrease), going to take all the star's volume.

My poor little brain is having trouble with that.

Microscopic objects like neutrons are not tiny balls; they are particles and waves. Imagine an electron in an atom. Do you think it's a small ball rotating around the nucleus, there? Or do you think it's a cloud smeared on the entire orbital? If you compute its position indeterminacy with HUP (Heisenberg Uncertainty Principle) you find that it equals the entire orbital. Now think to what happens if you clump together many atoms of Iron, for example. When they are still not very close, the volumes pertaining to the electrons are still the same, but as soon as the atoms bind together, the external electrons take the volume of all the external orbitals of the atoms, becoming so much more free. For this reason Iron is a metal, that is electrons are free to move inside of it.

[DoctorBeaver (OP)]

I think I understand that. Thank you.

[lyner]

DrB

I can't recall the last time I worked in a field apart from clearing up horse poo.

A farmer is an expert: A man out_standing in his field.

[DoctorBeaver (OP)]

DrB

I can't recall the last time I worked in a field apart from clearing up horse poo.

A farmer is an expert: A man out_standing in his field.

It will be a farmer who invents the tractor beam  []

[syhprum]

I allways thought that temperature was a measure of the kinetic energy of the particles making up a body, what happens to the concept of temperature when they are packed so tight that they cannot move ?

[lightarrow]

I allways thought that temperature was a measure of the kinetic energy of the particles making up a body, what happens to the concept of temperature when they are packed so tight that they cannot move ?

It's an interesting question and I sincerely cannot state to have a complete answer. However, if you take a gas inside a cylinder and you reduce the cylinder's volume isothermically (constant temperature), what you get is to reduce the particle's average free path, not their speeds, so you will have a constant increase of the collision's frequency; if you have a liquid or a solid it's quite the same, with a solid the only difference is that now you will talk of particle's vibrations around their equilibrium points, not of free movement, but the concept is quite the same.

I don't expect a much different behaviour from neutrons in a neutron star.

[lightarrow]

The Noddy answers are always the best.
I'm just waiting for lightarrow to point out something wrong with such a simple answer.

At the moment I couldn't find anything wrong about it, however let's remember that neutrons and protons are not elementary particles; making them close and close each other will probably result in a "plasma" of quarks and every quark is now more little than a nucleon. What could happen after that...is a total mistery.

[Soul Surfer]

it has been suggested that there is a further stable phase between neutron stars and black holes that of a "Quark star"  (google this)  The nucleons have merged to leave free quarks.  however as the size difference between a neutron star and a black hole is relatively quite small  their external properties will be quite similar.

[Mr. Scientist]

Measurement blah blah position harumph velocity mumble mumble; we all know the score by now.

So, in a neutron star there are all these neutrons (hardly surprising really). They're squeezed together very tightly by gravity; even tighter than Graham Norton and his "friend" at a Village People concert. Now if they're being squeezed together like that, surely it must restrict their movement somewhat. But do they have less freedom of position and velocity than ordinary neutrons at the centre of an atom? Could there come a point where their movement is so restricted by being squeezed together that the Uncertainty Principle either no longer applies or, at least, needs modifying?

They would certainly have more freedom as constituents of the nuetron star, than being confined to a nucleus. And despite the star being very dense, there is still a lot of space on their level of perspectives. For instance, the earth itself isn't very dense - but we compair this density stuff with a quick example.

A spoonful of nuetron star matter would be as heavy as all the cars and trucks of the earth. But theoretically, you could squeeze the entire earth into just the size of a spoonful into an infinite density.

Th nuetron star, as dense as it is, still has a lot of space seperating its nuetron components.