John Schilling kirjutas:
On 10 Jan 2007 14:50:25 -0800, "bbbl67" wrote:

On Jan 5, 2:36 am, Erik Max Francis wrote:
And, has been pointed out, if there's motion of the internal fluids
inside the rotating neutron star, that could also result in precession
and all kinds of lower-order rotational behaviors.

Now, I know the interior of a neutron star has been described as a
fluid. But I find it hard to believe that something so dense that its
neutrons are touching could be a fluid. Can the neutrons slip past one
another, somehow?

Of course. What would stop them?

In order for a thing to *not* be a fluid, something has to hold each
particle in a particular spot, and that something has to be the strongest
force at work in the system. In ordinary solid materials, a particular
arrangement of the electromagnetic force does this just fine.

In a neutron star, you've got A: neutrons, which are B: compressed to
such a density that gravity overwhelmes electromagnetism. If even
electromagnetism applied, which it doesn't because neutrons are
electrically neutral.

But you also have something that counteracts the gravity and stops the
neutrons from being compressed to decreasing volume and black hole.
Neutrons must repel each other.

And this means that the best way to minimize the repulsion is occupying
specific positions in space in a well-packed framework. Which would be
solid. Any change of shape would increase the mutual repulsions
somewhere.

And unless there's something funky going on in quantum gravity that
we haven't figured out yet, gravity is not a force for holding things
in a particular spot. Gravity is just fine with having particles flow
along equipotential surfaces, and actively *wants* particles to flow
downhill.