Theoretical question - what would happen?

[Cuetek]

[SOLVED] Theoretical question - what would happen?

What would happen to a cubic foot of neutrons if, say, you scooped them up off of a neutron star and kept them confined until you got away from it's grav field and then released them? Would they stay neutral? Would they give off any energy? would they separate from each other, expand? (If initial temp is an issue, presume the star had cooled to zero Celsius.)

 

[DaveC426913]

(If initial temp is an issue, presume the star had cooled to zero Celsius.)

This last criteria breaks it. Can't happen.

The neutron star is under incredibly high pressure, and thus incredibly hot.

To even get your ample, you'd have to have fabulously tough materials. And from there you can deduce what your cube of neutorns will want to do...

 

[Cuetek]

The neutron star is under incredibly high pressure, and thus incredibly hot.

Couldn't it radiate the initial heat away after billions of years?

 

[DaveC426913]

Couldn't it radiate the initial heat away after billions of years?

I don't think neutronium is stable in that sense. I think they'll decay rapidly into protons and electons (in about 15 minutes, according to wiki) if not under the heat and pressure. But I'm a bit out of my depth here.

 

[Anticitizen]

I believe I read somewhere that you would have a fairly massive explosion on your hands if the gravitational pull that was keeping the matter that dense were suddenly removed. Assuming you could teleport the neutronium somewhere else, that is.

 

[Cuetek]

I believe I read somewhere that you would have a fairly massive explosion on your hands if the gravitational pull that was keeping the matter that dense were suddenly removed. Assuming you could teleport the neutronium somewhere else, that is.

That's kind of what I figured. My question arises from pondering the difference between the big bang singularity and a black hole singularity. If one is emissive and the other compressive I was trying to figure out, just from a partial stage of the latter (neutron star, or perhaps more interestingly, the theoretical quark star) if you simply relieved such material from gravitational constraint, how similar to early big bang environs would it be? Specifically, would such gravitationally unencumbered nutronium form any hydrogen?

 

[DaveC426913]

That's kind of what I figured. My question arises from pondering the difference between the big bang singularity and a black hole singularity. If one is emissive and the other compressive I was trying to figure out, just from a partial stage of the latter (neutron star, or perhaps more interestingly, the theoretical quark star) if you simply relieved such material from gravitational constraint, how similar to early big bang environs would it be? Specifically, would such gravitationally unencumbered nutronium form any hydrogen?

The temperature after the BB was too hot even for matter to form; it had to cool significantly first before matter could even condense from energy.

 

[humanino]

Hi

My question arises from pondering the difference between the big bang singularity and a black hole singularity. If one is emissive and the other compressive I was trying to figure out, just from a partial stage of the latter (neutron star, or perhaps more interestingly, the theoretical quark star) if you simply relieved such material from gravitational constraint, how similar to early big bang environs would it be? Specifically, would such gravitationally unencumbered nutronium form any hydrogen?

Very good question, indeed, but watch out with easy analogies. I am not sure what you mean by "emissive" and "compressive" in particular, and anything from there gets fuzzy.

Maybe you are aware of the concept of "white hole", which should be the time-reversal of a black hole. It so happens however that due to quantum effects, black hole emit radiation at a temperature inversly proportional to the surface gravity. I do not claim to understand anything in those matters, therefore I quote Hawking whose opinion is that, for an extrenal observer, white holes and black holes are indistinguishable.

 

[Cuetek]

The temperature after the BB was too hot even for matter to form; it had to cool significantly first before matter could even condense from energy.

Since a neutron star would constitute an extremely (infinitely?) remote circumstance in terms of density/temp to the Big Bang singularity, modeling unencumbered neutronium occurs to me only as an extreme latter stage model. What I really want to know is whether or not local gravitational compression of matter in the current state of the universe is at all analogous to the state of matter at an equivalent stage of the Big Bang. That is, will gravitationally compressed contemporary matter decompress similarly to how Big Bang matter expanded in stages of similar density?

Your attention to heat in the above responses now occurs to me to be the essential variable. So I would now wonder if it is possible to achieve anywhere near the same temperature at a given density as was present at the same density in the Big Bang starting with contemporary matter and using only gravitational compression. Something tells me that it is not possible. But I would still be curious given sufficient heat, if post-Bang conditions are reversible to earlier-Bang condition from gravitational compression alone.

 

[shelanachium]

This could happen in reality - or something near to it. To see what happens when neutron-star material is liberated from a neutron star, observe a neutron-star coalescence, as in one type of gamma-ray burster. Most of the matter would end up in a black hole, but not all of it.

In your own case, presuming it could be done, you'd blow youself to Kingdom Come together with everyone within 1,000 miles.

 

[DaveC426913]

In your own case, presuming it could be done, you'd blow youself to Kingdom Come together with everyone within 1,000 miles.

I know you weren't being rigorous about it but - considering a cubic foot of neutronium is the equivalent of a cube of normal matter between 10 and 100 kilometers on a side - and that it may reexpand rather ... enthusiastically ... I'd say a 1000 mile damage radius might be a hair on the conservative side.

 

[cliffy]

What do you guys know about perpetual motion generators someone told me it was already patented but I can't find it in a patent search

 

[cliffy]

does anybody know how i calculate foot pound force of water pushed through X diameter given x PSI

 

[DaveC426913]

What do you guys know about perpetual motion generators someone told me it was already patented but I can't find it in a patent search

Perpetual Motion. Forget it.

 

[humanino]

Perpetual Motion. Forget it.

Black Hole Thermodynamics and Lorentz Symmetry

Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe the arguments leading to that conclusion. We suggest the implication that Lorentz symmetry should be viewed as an emergent property of the macroscopic world, required by the second law of black hole thermodynamics.

Sorry, I read the two things in like two minutes interval