neutron star rotation

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omghaxcode

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Feb 8, 2007
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if neutron stars aren't losing any mass and their radius is fixed, why does their rotation slow down? obviously it is losing mass somehow or conservation of momentum wouldn't hold, but how?
 

Hayabusa Rider

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The intense magnetic field associated with neutron stars creates a drag IIRC like a magnetic brake

Don't bet the farm on that. Been a lot of years since I read up on the subject.
 
May 11, 2008
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The intense magnetic field associated with neutron stars creates a drag IIRC like a magnetic brake

Don't bet the farm on that. Been a lot of years since I read up on the subject.

Just a silly question, since an neutron has no electrical charge and electrical charge and magnetic interaction are coupled. How can a neutron star have a magnetic field ? That would mean that a neutron star is not entirely build up of only neutrons. I have heard of the quarks theory though. I was hoping for a better explanation.
 

Hayabusa Rider

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The answer is that while a neutron is indeed electrically neutral the quarks which compose it are not. Neutrons have a magnetic moment. Remember too that the star isn't homogenious. The interior is postulated to be a superconducting superfluid so its nothing at all for the entire core to align creating what is in effect the strongest magnet in the universe.

BTW I did a little looking and the mechanism of slowing is indeed magnetic.
 
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May 11, 2008
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The answer is that while a neutron is indeed electrically neutral the quarks which compose it are not. Neutrons have a magnetic moment. Remember too that the star isn't homogenious.

That's my point, it is all a case of "my theory against your theory".

I am sure the neutron star is not comprised of a homogeneous material. No natural reaction that needs large amounts of energy is that perfect.

The interior is postulated to be a superconducting superfluid so its nothing at all for the entire core to align creating what is in effect the strongest magnet in the universe.

BTW I did a little looking and the mechanism of slowing is indeed magnetic.

That is funny that you mention that, i always assumed that superfluid states can exist not only at very low temperatures, but at very high temperatures a s well. Push it further and i would expect somthing similair like a bose einstein condensate. But then at high temperatures and high energies. This would be a black hole.


Why i would think that :
When looking at superconductors, they function at low temperatures, but since temperature and thermal noise are related, and thermal increase of energy is related to the amount of pressure or force applied to the material, i always found it obvious that high temperature superconducting materials can be formed as well.

http://www.sciencedaily.com/releases/2008/05/080519150608.htm





I
 

Hayabusa Rider

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Neutrons do have a magnetic moment. It's not a hypotheis or theory. Granted there aren't ways of directly measuring the neutron "soup", but the theories match observation.

It's somewhat akin to gravity. What it means and where it comes from are far from certain, yet there is no doubt that it exists. The precise nature of a neutron star isn't known. There's a whole lot about superdense states we don't understand. Nevertheless, until someone improves on the theory it's hard to argue against something that works. It's reasonable to assume that the top layers are of a dense solid, and disturbances at the superfluid/solid interface create the "glitches" we observe in rotational speed. It's always the boundary layers of different states that give us fits. Is there a gradual transition between states, or is it a sharp demarcation? I'd think the former however I can't prove it.

The things you are uncertain of are the most interesting :)
 
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