The Wikipedia article about neutron stars says that the outer crust is a weird high-pressure allotrope of iron, and that inside there are several phase changes between higher and higher pressure forms of exotic matter, many of these hypothetical. A "neutron superfluid" is one of them. On Wed, Jun 25, 2014 at 3:18 PM, Warren D Smith <warren.wds@gmail.com> wrote:
On 6/25/14, Whitfield Diffie <whitfield.diffie@gmail.com> wrote:
A better way to view this is: replace the word "stable" with "stable under pressure."
That just seems to me to diddling the rules; a neutron star isn't under external pressure; it is in free space. The important point is that a nucleus has to become quite large before the gravitational force begins to play a role in its stability.
--The pressure is created by gravity & the weight of the matter on top of it. A "true" neutron star in free space. i.e. composed entirely of neutrons, likely could not exist. In order for a neutron star to exist it presumably must have "normal" matter in the outer layers, neutrons being unstable if not under pressure. As we go inward, larger and larger nuclei will be able to exist until eventually we reach a region which could be regarded as "one big nucleus."
Now if somehow enormous pressure were externally exerted by nongravitational means, then "neutronium" presumably could stably exist in much smaller chunks than a neutron star.
Incidentally, in certain sci-fi stories by Larry Niven, he has chunks of neutronium the mass of, e.g. the Moon, or less, sitting around being used for various purposes. That was bullshit, any such chunk should experience an enormous explosion immediately.
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