Thought experiments with neutron star

Dne 28.6.2014 0:10, Sjouke Burry napsal(a):
On 27.06.14 8:41, Poutnik wrote:

What would happen to a "piece of neutron star",
if it was by whatever process cut out from NS,
and had low enough mass ?

Would the degenerate neutron pressure cause
explosion and neutron showers ?

Or, would it become non-degenerated NS ?

Or, would it recompose to back to iron-nickel
and their electrons, forming Fe-Ni white dwarf ?

The only reason, that degenerate matter does stay in one place,
is gravity.
Take away the gravity and atoms disengage with the force of a
hydrogen bomb explosion.

Fusion energy is squeezed out already.

--
Poutnik

Wise man guards the words he says,
as they may speak about him more, than about the subject.

On 30.06.14 7:30, Poutnik wrote:
Dne 28.6.2014 0:10, Sjouke Burry napsal(a):
On 27.06.14 8:41, Poutnik wrote:

What would happen to a "piece of neutron star",
if it was by whatever process cut out from NS,
and had low enough mass ?

Would the degenerate neutron pressure cause
explosion and neutron showers ?

Or, would it become non-degenerated NS ?

Or, would it recompose to back to iron-nickel
and their electrons, forming Fe-Ni white dwarf ?

The only reason, that degenerate matter does stay in one place,
is gravity.
Take away the gravity and atoms disengage with the force of a
hydrogen bomb explosion.

Fusion energy is squeezed out already.

But compression energy is not, those particles dont WANT to stay
together, and they will demonstrate that violently.

Dne 1.7.2014 1:48, Sjouke Burry napsal(a):
On 30.06.14 7:30, Poutnik wrote:
Dne 28.6.2014 0:10, Sjouke Burry napsal(a):
On 27.06.14 8:41, Poutnik wrote:

What would happen to a "piece of neutron star",
if it was by whatever process cut out from NS,
and had low enough mass ?

Would the degenerate neutron pressure cause
explosion and neutron showers ?

Or, would it become non-degenerated NS ?

Or, would it recompose to back to iron-nickel
and their electrons, forming Fe-Ni white dwarf ?

The only reason, that degenerate matter does stay in one place,
is gravity.
Take away the gravity and atoms disengage with the force of a
hydrogen bomb explosion.

Fusion energy is squeezed out already.

But compression energy is not, those particles dont WANT to stay
together, and they will demonstrate that violently.

Perhaps, but I guess this energy first has to be added
by neutron star desintegration,
as there is additionally sqeezed out also gravitational energy.

IMHO NS has lower energy than carbon-oxygen white dwarf,
iron star core or free nucleons of the same nucleon count.

--
Poutnik

Wise man guards the words he says,
as they may speak about him more, than about the subject.

On 01.07.14 7:01, Poutnik wrote:
Dne 1.7.2014 1:48, Sjouke Burry napsal(a):
On 30.06.14 7:30, Poutnik wrote:
Dne 28.6.2014 0:10, Sjouke Burry napsal(a):
On 27.06.14 8:41, Poutnik wrote:

What would happen to a "piece of neutron star",
if it was by whatever process cut out from NS,
and had low enough mass ?

Would the degenerate neutron pressure cause
explosion and neutron showers ?

Or, would it become non-degenerated NS ?

Or, would it recompose to back to iron-nickel
and their electrons, forming Fe-Ni white dwarf ?

The only reason, that degenerate matter does stay in one place,
is gravity.
Take away the gravity and atoms disengage with the force of a
hydrogen bomb explosion.

Fusion energy is squeezed out already.

But compression energy is not, those particles dont WANT to stay
together, and they will demonstrate that violently.

Perhaps, but I guess this energy first has to be added
by neutron star disintegration,
as there is additionally squeezed out also gravitational energy.

IMHO NS has lower energy than carbon-oxygen white dwarf,
iron star core or free nucleons of the same nucleon count.

Surface gravity is about 10^11 G or 100000000000 G.
So there is an awful lot of gravitational energy squeezing those
neutrons together.
Without that gravity the neutron star would never come into being.
(Almost) free neutrons have a halve life of 15 seconds,
So your "piece of neutron star" would violently convert to protons and
electrons(or their antimatter counterparts), once you remove it from
the star.

On 07/01/2014 09:04 AM, Sjouke Burry wrote:
On 01.07.14 7:01, Poutnik wrote:

Perhaps, but I guess this energy first has to be added
by neutron star disintegration,
as there is additionally squeezed out also gravitational energy.

IMHO NS has lower energy than carbon-oxygen white dwarf,
iron star core or free nucleons of the same nucleon count.

Surface gravity is about 10^11 G or 100000000000 G.
So there is an awful lot of gravitational energy squeezing those
neutrons together.

Without that gravity the neutron star would never come into being.
(Almost) free neutrons have a halve life of 15 seconds,

So your "piece of neutron star" would violently convert to protons and
electrons(or their antimatter counterparts), once you remove it from
the star.

Only if you provide them energy they had before star fusion
by neutron star desintegrating.

I would expect rather reversed degenerated iron 2 neutron star process.

--
Poutnik

A wise man guards words he says,
as they may say about him more, than he says about the subject.

On 01/07/2014 5:57 AM, Poutnik wrote:
On 07/01/2014 09:04 AM, Sjouke Burry wrote:
So your "piece of neutron star" would violently convert to protons and
electrons(or their antimatter counterparts), once you remove it from
the star.

Only if you provide them energy they had before star fusion
by neutron star desintegrating.

I would expect rather reversed degenerated iron 2 neutron star process.

The neutrons degenerate due to the Weak Nuclear Force, not due to the
leftover heat of star fusion.

Yousuf Khan

On 07/02/2014 06:00 PM, Yousuf Khan wrote:
On 01/07/2014 5:57 AM, Poutnik wrote:
On 07/01/2014 09:04 AM, Sjouke Burry wrote:
So your "piece of neutron star" would violently convert to protons and
electrons(or their antimatter counterparts), once you remove it from
the star.

Only if you provide them energy they had before star fusion
by neutron star desintegrating.

I would expect rather reversed degenerated iron 2 neutron star process.

The neutrons degenerate due to the Weak Nuclear Force, not due to the
leftover heat of star fusion.

Yousuf Khan

The neutrons are created via Weak force from heavy nuclei,
with electrons being pushed close enough to nuclei by gravity pressure.

Note that by calculation for M = 1.2M?sol and R=10 km,
I have calculated gravitation energy about -70 MeV/nucleon,
what is about 10 times more than hydrogen to helium fusion.

https://en.wikipedia.org/wiki/Neutron_star#Properties
https://en.wikipedia.org/wiki/Gravit...binding_energy

Then neutrons are by gravity pressure forced
to gain higher energy by degeneration,
what created degeneration pressure acting against.

It is because of Fermi-Dirac statistics,
similarly as for electron degeneration.

As if their wave functions overlap,
thay cannot share the same quantum state.

--------------

Both electron and neutron degeneracy energy and pressure
can be visualized by set of small balls placed on the desk.

The position of balls are like quantum states.
You cannot have 2 balls in the same 3D place.

If you fence them by some walls and start shrinking them,
at some point they form the 2nd, 3rd, 4th upper layers.
so many as needed.

You need stronger and stronger force per fence length
to perform sqeezing of ball area on the table.

And this is degeneracy pressure of table balls
and balls in multiple layers are in ball degeneracy state.


--
Poutnik

A wise man guards words he says,
as they may say about him more, than he says about the subject.

In article ,
Poutnik writes:
What would happen to a "piece of neutron star",
if it was by whatever process cut out from NS,
and had low enough mass ?

If the "piece" is just one neutron, it would decay with the usual
half life. If it's larger, what happens depends on how you remove it
and in particular how quickly you release the pressure. Once the
pressure is released, the material would expand, and the neutrons
would decay in the usual way. If the mass is low and nothing
maintains external pressure, the material cannot remain degenerate.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On 07/08/2014 07:42 PM, Steve Willner wrote:
In article ,
Poutnik writes:
What would happen to a "piece of neutron star",
if it was by whatever process cut out from NS,
and had low enough mass ?

If the "piece" is just one neutron, it would decay with the usual
half life. If it's larger, what happens depends on how you remove it
and in particular how quickly you release the pressure. Once the
pressure is released, the material would expand, and the neutrons
would decay in the usual way. If the mass is low and nothing
maintains external pressure, the material cannot remain degenerate.

I mean if ***hypothetically**** by 2 neutron star collision happens
1 of them is ripped apart to 2 or more big pieces
with mass under supposed low neutron stars limit..

All is also matter of energy per nucleon,
concerning energy released/needed to gain wrt stron interaction and gravity.



--
Poutnik

A wise man guards words he says,
as they may say about him more, than he says about the subject.

On 30/06/2014 1:24 AM, Poutnik wrote:
Dne 27.6.2014 16:29, Yousuf Khan napsal(a):
On 27/06/2014 2:41 AM, Poutnik wrote:
Or, would it recompose to back to iron-nickel
and their electrons, forming Fe-Ni white dwarf ?

The material stays in the form of neutrons because of gravity. If there
isn't enough gravity, then the neutrons will go flying off in a
spectacular explosion. I don't think it will turn back into Nickel or
Iron, but rather back into Hydrogen. All of the neutrons will go their
separate ways, so that would mean they would revert back to their
simplest states which is one neutron which would decay into a proton and
an electron, which is of course hydrogen.


Hmmm.

It would close the cycle
hydrogen - helium - carbon ....... iron
back to hydrogen.

Iron has lower energy per nucleon than hydrogen,
even lowered by gravitation potential of NS.

Is theoretical energy to "dig out" matter out from NS
high enough to return energy per nucleon to original hydrogen ?

Once the material has been deposited onto a neutron star, the gravity
breaks all of their chemical nuclear bonds apart. Except maybe at the
top most layers of the star, where the pressure isn't too high yet, they
may retain their chemical nuclear bonds for a while yet. That's
basically white dwarf material acting as the crust of the neutron star.

Below the crust, the neutron star, would have broken all of those
nuclear bonds apart and turned them all into individual protons and
neutrons. That would be the mantle of the neutron star.

Below that, a neutron star's core might have nothing but neutrons, as
all electrons will have been crushed into their protons at those
pressure levels. Now, some of the very most massive neutron stars (i.e.
not all of them) may have an even more inner core, which would be likely
made of strange matter, which is basically a free quark-gluon soup.

So getting back your original question, lifting off some neutron star
material won't result in it reverting back to high-level chemical
elements, but rather the most basic chemical element, hydrogen.

Yousuf Khan