[X] My Assistant

[deglr6328]

I think Jeff is talking about the so called "superheavy atoms" in the island of stability that is predicted to occur at around N=184. We can at least conclude I think, that nature, when producing a supernova, is quite capable of producing anything that we are in the laboratory and that would therefore take us up to around 114 (or "Ununquadium" if you like) on the periodic table. It would seem a very minor stretch therefore to imagine that a supernova could easily add a mere ~10-20 nucleons to that size and reach the ~184 N "magic number" region of stability. Though I am unaware if there are any predictions of what "stable" means at these weights. It may mean a nanosecond for all I know. It is interesting to note though that there is currently a (some say very optomistic) experiment in France whoch is looking for the natural decay of Hassium-292 in a sample of osmium deep underground in a cave somewhere.

[Guest_Richard Trigaux_*]

Interesting side note on heavy elements - I wonder what the heaviest natural element is? We think of it as being uranium, but that's probably because anything heavier than that has decayed already. Look at some of these super-heavy elements being created artificially - half lives of only a few seconds, if even that long, and then they decay into lighter things. I just wonder how big of an atom an imploding star could produce, if it'd only last for a fraction of a second. Granted, not like it really matters to us...just a curiosity though.

Besides the story at n=184 that deglr6328 speaks about, you may consider that in the highest conditions of pressure in some star cores, in may happen that elements which are unstable on Earth become stable. At the extreme we can consider that a neutron star is a giant atom nucleus bound by gravity. So we may ask two question:
1) in the very last stage of fusion in a dying star, some minutes before the explosion, some super-heavy atoms may be stable, with perhaps thousand or million of nucleons. (of course we find no traces of them after the explosion, because they become part of the neutron star, or if they escape they find normal conditions and decay very fast)
2) if a neutron star could break apart, what would be the minimum mass able to remain bound by gravitation?

[deglr6328]

A neutron star, in some ways, may also be thought of as one huge atom! A neutron star which has lost mass through some mechanism would eventually pass the point at which the force of the nuclear degeneracy pressure exceeds that of the force of gravity and the star would then detonate with extreme violence.

[Guest_Richard Trigaux_*]

A neutron star, in some ways, may also be thought of as one huge atom!    A neutron star which has lost mass through some mechanism would eventually pass the point at which the force of the nuclear degeneracy pressure exceeds that of the force of gravity and the star would then detonate with extreme violence.

Yes it would, but if you think in depth, the energy of the detonatoin would have to be BROUGHT IN the neutron star by the mechanism able to break it (it will have to yeld a tremendous amount of energy to split apart the parts of the neutron star.) So this is, I think, rather unlikely to happen, and coalescence of two neutron stars or black holes may just yeld larger neutron stars/black holes. But eventually the process may produce jets (like in quasars) containing tiny fragment of neutronic matter. What is the smallest limit allowed for such a fragment to remaint bound by gravitation and avoid decaying/detonating? 0.1 solar mass? Earth mass? 1 kilog? 1 microgram?
A hint that such lumps of neutronic matter could be small is that I heard it exist "nucleus" formed of... four neutrons. Of course in this case they are bound by the strong nuclear force, and anyway still unstable. The pressure of gravity must be strong enough to avoid the neutron to decay, and this may set the limit.


Anyway a small lump of neutronic matter will be surrounded by a layer of ordinary matter, and look like a very small star of unusual properties, or like a white dwarf of higher density. If the lump can be very small, for instance 1m (about the mass of Earth) it may look like a star of some metres in diametre, but hot like a star!



Another place where we could find giant atoms is the outer layer of a neutron star. Neutron stars still obey the common laws of physics, and chemical bodies get states according to their pressure and temperature. And a neutron star has an outer atmosphere of ordinary gas which pressure tends to zero when we get farther from the surface. Simply this layer is some millimetres thick, this is enough for the tremendous gravitation field to allow a very hight pressure and keep bodies solid. So, when we examine a neutron star from outside to inside, we may find, in a distance of some centimetres:
1) ordinary plasma
2) white dwarf-like degenerated solid matter, formed or iron nucleus and felectrons
3) perhaps a layer where pressure allows the existence of much larger nucleus than authorized in usual conditions. But this layer may be unstable and in this case we would have an abrupt transition to:
4) neutronic matter.

[deglr6328]

Yes it would, but if you think in depth, the energy of the detonatoin would have to be BROUGHT IN the neutron star by the mechanism able to break it (it will have to yeld a tremendous amount of energy to split apart the parts of the neutron star.) So this is, I think, rather unlikely to happen, and coalescence of two neutron stars or black holes may just yeld larger neutron stars/black holes.

I don't know, imagine a neutron star orbiting a black hole within the Roche limit, material will be sucked off of the surface simillar to what is shown here. If the rate of material loss from the neutron star is sufficient that its mass falls below the critical degeneracy pressure limit before it falls past the schwartzchild radius then we should see an explosion. Though I am not a supercomputer so I could not tell you if this is theoretically feasible or not.

[Guest_Richard Trigaux_*]

I don't know, imagine a neutron star orbiting a black hole within the Roche limit, material will be sucked off of the surface simillar to what is shown here. If the rate of material loss from the neutron star is sufficient that its mass falls below the critical degeneracy pressure limit before it falls past the schwartzchild radius then we should see an explosion. Though I am not a supercomputer so I could not tell you if this is theoretically feasible or not.

Perhaps a black hole is able to suck matter of a neutron star? In this case, the neutron star could become smaller than the minimum limit to form (about 1.3 solar mass). How much smaller? if the neutron star becomes too small, it cannot be sucked by the black hole, or it may fall in it completelly. Before it explodes?

[Guest_Richard Trigaux_*]

back to topic: small neutron stars can form by Intelligent Design

[ljk4-1]

Perhaps a black hole is able to suck matter of a neutron star? In this case,  the neutron star could become smaller than the minimum limit to form (about 1.3 solar mass).  How much smaller? if the neutron star becomes too small, it cannot be sucked by the black hole, or it may fall in it completelly.  Before it explodes?

Have any neutron stars with (suspected) black hole companions been found?

[Guest_Richard Trigaux_*]

Have any neutron stars with (suspected) black hole companions been found?

AS far as I know no, but I read speculations about that. A couple of black holes has been found, so that the phenomenon is not uncommon or impossible. From relativity, two massive objects in close orbit are not stable, and the orbits goes closer and closer, until the two bodies coalesce. There has been some studies about this, as such phenomenon are expected to be the most poweful source of transcient gravity waves.


The difficulty in removing mass to a neutron star is that it is already in a very low energy level (all its energy dissipated during the formation, mainly under the form of thermal neutrinos). So to make it explode we must first bring the energy of the explosion, so me need more energy to remove mass than what was dissipated during the formation. But of course if we succeed in doing so, the neutron star can explode. What deglr6328 proposed is that a black hole could do so.

[dvandorn]

Well, yeah, a black hole would be the only thing that would have the raw power to strip material off of a neutron star. But I have serious questions as to what the process of such mass-stripping would look like -- it would seem to me that it would be so difficult to get fragments of a neutron star to break off of their parent body that it would tend to retain its cohesion until after it was safely within the Schwartzchild radius of the black hole...

-the other Doug

[Guest_Richard Trigaux_*]

Well, yeah, a black hole would be the only thing that would have the raw power to strip material off of a neutron star.  But I have serious questions as to what the process of such mass-stripping would look like -- it would seem to me that it would be so difficult to get fragments of a neutron star to break off of their parent body that it would tend to retain its cohesion until after it was safely within the Schwartzchild radius of the black hole...

-the other Doug

Not sure. remember that a neutron star is about the same radius than the Schwartzchild sphere of a small black hole. So we can imagine that part of it is in, while most of it is still out. But at this stage, anyway, the complete coalescence is within some minutes or seconds of time, and the orbit is even no more circular, it is chaotic (and still more chaotic if the black hole rotates). So we can imagine that the neutron star is eaten by bits, each times it gets close enough.

Anyway a neutron star is something extremely solid, but even this solidity is very weak in front of its gravitation. I am sure, there are some known example of "neutron star quakes" which occur when the rotation speed changes, and the shapes changes from more to less elliptic. So the gravitation of a neutron star is much stronger that its material solidity. Anyway a hand into the Schwartzchild sphere and the remainder of the body out, nothing can resist to this.

We can imagine this tremendous catastrophe: each stripping is an enormous burst of energy, a series of cracks for some seconds before the remainder of the neutron star is swallowed, or it explodes from having no more enough gravitation left to resist the tremendous pressure of the neutronic matter.

[ljk4-1]

This fellow co-authored papers with Ward and Brownlee on Galactic Habitable Zones (GHZ). According to him, it would seem that Earth is the only planet in the entire galaxy in a life happy place. And guess how we all got here?

http://www.spacedaily.com/news/life-01o.html


Gonzalez, Iowa State’s "Wizard of ID," on defensive

Iowa State astronomy assistant and Intelligent Design supporter Guillermo Gonzalez says his critics have got him wrong.

By Kevin Ferguson

(November 10, 2005)

http://www.stnews.org/articles.php?categor...article_id=2170

[jamescanvin]

Not sure. remember that a neutron star is about the same radius than the Schwartzchild sphere of a small black hole. So we can imagine that part of it is in, while most of it is still out. But at this stage, anyway, the complete coalescence is within some minutes or seconds of time, and the orbit is even no more circular, it is chaotic (and still more chaotic if the black hole rotates). So we can imagine that the neutron star is eaten by bits, each times it gets close enough.

Note that orbits within about 3 Rs are unstable (allthough this can be less in a Kerr (rotating) black hole. So I don't really think we can imagine an orbit with part of the neutron star inside the Event horizon.

Anyway a neutron star is something extremely solid, but even this solidity is very weak in front of its gravitation. I am sure, there are some known example of "neutron star quakes" which occur when the rotation speed changes, and the shapes changes from more to less elliptic. So the gravitation of a neutron star is much stronger that its material solidity. Anyway a hand into the Schwartzchild sphere and the remainder of the body out, nothing can resist to this.

Neuton stars are not "extremely solid" on the contrary most of there interior is superfluid. Only the crust is solid which is where the quakes occur, when, as you say the shape of the star changes.

We can imagine this tremendous catastrophe: each stripping is an enormous burst of energy, a series of cracks for some seconds before the remainder of the neutron star is swallowed, or it explodes from having no more enough gravitation left to resist the tremendous pressure of the neutronic matter.

I'm not in a position to think about this much at the moment (a cold is stopping my brain from working!) but my first guess would be that the NS would be consumed pretty much whole. The only other scenario I can think of would be where tidal effects stretch the star so such an extent that gravity is no longer able to hold it together (like as been said above) however I don't think this likley for the following reasons:

1) NS's are really small so you would need one hell of a tidal force in the first place.
2) NS's hold there shape really well, these are objects that can rotate 100's of times per second and still stay together in a roughly sperical shape so an even higher gradient is needed.
3) for this to work the NS would have to be tidally locked to the BH this is hard due to the very good level of symmetry of the NS and the high rotation rate.
4) the NS would have to be fairly close to the lower mass limit which (I think) is probably quite rare.

I just don't think the gravitational gradient is strong enough to do this, even within the last stable orbit of a BH. (Note no calculations done to justify all this, just belef )

James

[Guest_Richard Trigaux_*]

This fellow co-authored papers with Ward and Brownlee on Galactic Habitable Zones (GHZ).  According to him, it would seem that Earth is the only planet in the entire galaxy in a life happy place.  And guess how we all got here?

http://www.spacedaily.com/news/life-01o.html
Gonzalez, Iowa State’s "Wizard of ID," on defensive

Iowa State astronomy assistant and Intelligent Design supporter Guillermo Gonzalez says his critics have got him wrong.

By Kevin Ferguson

(November 10, 2005)

http://www.stnews.org/articles.php?categor...article_id=2170

I am afraid that, for the moment and for still a long time ahead, the hypothesis of intelligent life on other planets is intestable, so that we cannot make any statement about it, either positive (many civilizations) or negative (we are alone). We can only extrapolate from known astrophysical conditions, which say that life possibilities are many in the universe, while observing that we never reveived any visit from another civilization. This condradiction by itself is a puzzle.



As to the arguments of the studies themselves, they say our galaxy and the Sun are priviledged. This is not true. Our galaxy is very ordinary. The Sun, they say, has a special orbit, avoiding the dangerous regions of the nucleus. But the large majority of stars are such. They say the Sun has a special amount of "metals". Again many stars are metal-rich. We can suspect that metal-poor stars still form planets, and even that the spiraling of the primordial accretion ring left a given amount of planets in orbit, so that the size of planets does not depends on the metallicity of the star (unless of course they are metal-zero).

"The intense radiation and gravitation of a spiral arm would cause disruptions in our Solar System just as surely as if we were closer to the center of the Galaxy.

this and the following discution is bogus: the galactic gravitationnal field in arms is still very weak compared to the one in the solar system. And anyway there are billion of stars in the outer skirts of the galaxy which never cross the arms, so it is sheer exageration to say that our Sun would be alone to do so. This looks rather as an one-way argumentation to convince unacknowledged public than a fair scientific estimate of possibilities.


If I understand well, ID proponents are trying to persuade us that we are alone. This is a strange contradiction for people who say they are spiritual (spirituality loves life, so it can only hope to find many inhabited planets and foster research and welcome any discovery in this domain). This may indicate that ID proponents are not spiritual people, but religious nuts or fundamentalists (Earth only adobe for life is a re-hash of obscure Middle Age dogmas).

All this ID affair is really a mess, because finding evidences of a purpose for the universe (even tenuous, like anthropism) is an enthraling discution. But for long this topic will be associated with religious nuts who want to come back to the Middle Age.

[Guest_Richard Trigaux_*]

Note that orbits within about 3 Rs are unstable (allthough this can be less in a Kerr (rotating) black hole. So I don't really think we can imagine an orbit with part of the neutron star inside the Event horizon. 
Neuton stars are not "extremely solid" on the contrary most of there interior is superfluid. Only the crust is solid which is where the quakes occur, when, as you say the shape of the star changes.
I'm not in a position to think about this much at the moment (a cold is stopping my brain from working!) but my first guess would be that the NS would be consumed pretty much whole. The only other scenario I can think of would be where tidal effects stretch the star so such an extent that gravity is no longer able to hold it together (like as been said above) however I don't think this likley for the following reasons:

1) NS's are really small so you would need one hell of a tidal force in the first place.
2) NS's hold there shape really well, these are objects that can rotate 100's of times per second and still stay together in a roughly sperical shape so an even higher gradient is needed.
3) for this to work the NS would have to be tidally locked to the BH this is hard due to the very good level of symmetry of the NS and the high rotation rate.
4) the NS would have to be fairly close to the lower mass limit which (I think) is probably quite rare.

I just don't think the gravitational gradient is strong enough to do this, even within the last stable orbit of a BH. (Note no calculations done to justify all this, just belef )

James

Neutron stars hold their shape from gravitation which treats them as if they were fluid, even the super-resistant crust. In the case of super fast rotating neutron star, they keep from flying appart from the intense gravitation field, not from the resistance of the crust.

The phenomenon of the black hole stripping the neutron star would take place during some seconds, during the very last chaotic orbits. The smaller the black hole, the better the chance for this scenario (a giant galactic black hole would swallow the neutron star at once and entirely). Especially that neutron stars are often larger than black holes. Anyway the gravitation field and gradient of a black hole is larger than the one of a neutron star, so that there are many chances to see the neutron star split even in the case it comes straight ahead on the black hole.